Glacier Inventory and Glacier Change 1988–2009 5 Glacier Change Results B

icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion The Cryosphere Discuss., 5, 3541–3594, 2011 www.the-cryosphere-discuss.net/5/3541/2011/ The Cryosphere doi:10.5194/tcd-5-3541-2011 Discussions TCD © Author(s) 2011. CC Attribution 3.0 License. 5, 3541–3594, 2011

This discussion paper is/has been under review for the journal The Cryosphere (TC). Glacier inventory and Please refer to the corresponding ﬁnal paper in TC if available. glacier change 1988–2009 A new glacier inventory for 2009 reveals B. J. Davies et al. spatial and temporal variability in glacier Title Page response to atmospheric warming in the Abstract Introduction

Northern Antarctic Peninsula, 1988–2009 Conclusions References

B. J. Davies1, J. L. Carrivick2, N. F. Glasser1, M. J. Hambrey1, and J. L. Smellie3 Tables Figures

1 Centre for Glaciology, Institute for Geography and Earth Sciences, Aberystwyth University, J I Llandinam Building, Penglais Campus, Aberystwyth SY23 3DB, UK 2 Department of Geography, University of Leeds, Leeds LS2 9JT, UK J I 3Department of Geology, University of Leicester, Leicester LE1 7RH, UK Back Close Received: 2 December 2011 – Accepted: 8 December 2011 – Published: 21 December 2011 Full Screen / Esc Correspondence to: B. J. Davies ([email protected])

Published by Copernicus Publications on behalf of the European Geosciences Union. Printer-friendly Version

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3541 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Abstract The Northern Antarctic Peninsula has recently exhibited ice-shelf disintegration, glacier TCD recession and acceleration. However, the dynamic response of land-terminating, ice- 5, 3541–3594, 2011 shelf tributary and tidewater glaciers has not yet been quantified or assessed for vari- 5 ability, and there are sparse published data for glacier classification, morphology, area, length or altitude. This paper firstly uses ASTER images from 2009 and a SPIRIT DEM Glacier inventory and from 2006 to classify the area, length, altitude, slope, aspect, geomorphology, type and glacier change hypsometry of 194 glaciers on Trinity Peninsula, Vega Island and James Ross Island. 1988–2009 Secondly, this paper uses LANDSAT-4 and ASTER images from 1988 and 2001 and B. J. Davies et al. 10 data from the Antarctic Digital Database (ADD) from 1997 to document glacier change 1988–2009. From 1988–2001, 90 % of glaciers receded, and from 2001–2009, 79 % receded. Glaciers on the western side of Trinity Peninsula retreated relatively little. On Title Page the eastern side of Trinity Peninsula, the rate of recession of ice-shelf tributary glaciers has slowed from 12.9 km2 a−1 (1988–2001) to 2.4 km2 a−1 (2001–2009). Tidewater Abstract Introduction

15 glaciers on the drier, cooler Eastern Trinity Peninsula experienced fastest recession Conclusions References from 1988–2001, with limited frontal retreat after 2001. Land-terminating glaciers on James Ross Island also retreated fastest in the period 1988–2001. Large tidewater Tables Figures glaciers on James Ross Island are now declining in areal extent at rates of up to 2 −1 0.04 km a . This east-west difference is largely a result of orographic temperature J I 20 and precipitation gradients across the Antarctic Peninsula. Strong variability in tidewater glacier recession rates may result from the influence of glacier length, altitude, J I slope and hypsometry on glacier mass balance. High snowfall means that the glaciers Back Close on the Western Peninsula are not currently rapidly receding. Recession rates on the eastern side of Trinity Peninsula are slowing as the floating ice tongues retreat into the Full Screen / Esc 25 fjords and the glaciers reach a new dynamic equilibrium. The rapid glacier recession of tidewater glaciers on James Ross Island is likely to continue because of their low Printer-friendly Version elevations and flat profiles. In contrast, the higher and steeper tidewater glaciers on Interactive Discussion the Eastern Antarctic Peninsula will attain more stable frontal positions after low-lying ablation areas are removed. 3542 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 1 Introduction TCD The Northern Antarctic Peninsula Ice Sheet is particularly dynamic and sensitive to climate change because of its relatively small size and northern location (Vaughan 5, 3541–3594, 2011 et al., 2003; Smith and Anderson, 2010). The Antarctic Peninsula region is also one 5 of the most rapidly warming places on Earth, with mean air temperature increasing by Glacier inventory and ◦ 2.5 C over the last 50 yr (King, 1994; Turner et al., 2005). With continued atmospheric glacier change warming predicted for the Antarctic Peninsula region over the next century (Vaughan 1988–2009 et al., 2003), the viability of glaciers in this region is questionable. With this warming trend, the −9 ◦C annual isotherm (the thermal limit of ice shelves (Morris and Vaughan, B. J. Davies et al. 2 10 2003)) has moved southwards, resulting in 28 000 km being lost from Antarctic Penin- sula ice shelves since 1960 (Vaughan and Doake, 1996; Cook et al., 2005; Cook and Vaughan, 2010). Ice-shelf tributary glaciers accelerated and thinned following the dis- Title Page

integration of Larsen Ice Shelf (De Angelis and Skvarca, 2003), with up to a six-fold Abstract Introduction increase in centre-line speeds (Scambos et al., 2004). Other tidewater glaciers on the 15 Antarctic Peninsula are accelerating, thinning and retreating in response to increased Conclusions References atmospheric and sea surface temperatures (Pritchard and Vaughan, 2007). Antarc- Tables Figures tic Peninsula glaciers currently contribute 0.22 ± 0.16 mm a−1 to sea level rise (Hock et al., 2009), and have a total eustatic sea-level equivalent of 0.24 m (Pritchard and Vaughan, 2007). It is clearly important to establish how the on-going mass balance J I

20 changes and associated thinning, drawdown and ice front retreat will progress, and J I how these changes will impact future on sea level. Glacier inventory mapping is an essential prerequisite for regional mass balance Back Close

studies and for modelling future glacier extents (Abermann et al., 2009). It is therefore Full Screen / Esc surprising, given the glaciological responses to climate change outlined above, that 25 a detailed and up-to-date glacier inventory does not exist for the Northern Antarctic Printer-friendly Version Peninsula (Racoviteanu et al., 2009; Leclercq et al., 2011). Previous inventories have focussed on changes up to 2001, and contain few quantitative data suitable for inven- Interactive Discussion tory and numerical modelling purposes (Rabassa et al., 1982; Skvarca et al., 1995; Rau

3543 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion et al., 2004). What is particularly lacking is data on how glaciers have responded to climate change across the Northern Peninsula on a local scale; i.e. with respect to the TCD varied geological, climatic and glaciological settings. For example, there are outstand- 5, 3541–3594, 2011 ing questions regarding how the tributary glaciers on James Ross Island and Northeast 5 Antarctic Peninsula have changed since the 1995 disintegration of Prince Gustav Ice Shelf (PGIS) (cf., Rott et al., 1996; Glasser et al., 2011), and the likely future behaviour Glacier inventory and of these glaciers. Since PGIS was the ﬁrst regional ice shelf to disintegrate on the East- glacier change ern Antarctic Peninsula, the comparatively long time elapsed since that event oﬀers an 1988–2009 unusual opportunity to analyse the consequential response of tidewater and ice-shelf B. J. Davies et al. 10 tributary glaciers to ice shelf removal. This paper aims to create an inventory of the glaciers of Trinity Peninsula, James Ross Island and Vega Island (Fig. 1). Our comprehensive survey includes not only Title Page glacier length and area, as in previous inventories of James Ross Island (cf., Rabassa et al., 1982; Skvarca et al., 1995; Rau et al., 2004), but also coordinates, glacier ge- Abstract Introduction 15 ometry, geomorphology, elevation, aspect, slope, hypsometry, equilibrium line altitude (ELA), width of calving front, terminal environment, snow coverage and topographic Conclusions References

context. Secondly, we use this new dataset to analyse change in glacier extent between Tables Figures 1988, 1997, 2001 and 2009. These parameters provide the basis for the first comprehensive and holistic understanding of changes in Antarctic Peninsula ice shelves, J I 20 tributary glaciers, tidewater glaciers and land-terminating glaciers over the past two decades. This paper therefore has five specific objectives: (i) to map the length and J I extent of each individual glacier in 1988, 1997, 2001 and 2009; (ii) to identify pa- Back Close rameters for each glacier in line with the GLIMS (Global Land Ice Measurements from Space; www.glims.org) programme (cf., Racoviteanu et al., 2009); (iii) to establish rates Full Screen / Esc 25 of recession for these glaciers from 1988 to 2009; (iv) to analyse spatial and temporal variability in recession rates, and (v) to determine controls upon recession rates. Printer-friendly Version

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3544 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 2 Regional setting TCD 2.1 Location and climate 5, 3541–3594, 2011 Trinity Peninsula is the northernmost part of Graham Land, Northern Antarctic Penin- sula (Fig. 1). The region of interest for this paper extends from Cape Dubouzet (63◦ S, ◦ ◦ ◦ Glacier inventory and 5 57 W) to Larsen Inlet (64 S, 59 W). James Ross Island is separated from the Antarctic glacier change Peninsula by Prince Gustav Channel, which is 8 to 24 km wide (Fig. 1). Water depths 1988–2009 reach 1200 m and shallow southwards to less than 450 m (Evans et al., 2005). The north-south orientated Antarctic Peninsula mountains are an orographic barrier to per- B. J. Davies et al. sistent Southern Ocean westerlies. Cold continental air in the Weddell Sea also flows 10 northwards, barring the warmer maritime air masses of the Bellingshausen Sea (King et al., 2003). The Western Antarctic Peninsula therefore has a polar maritime climate, Title Page dominated by the warm Bellingshausen Sea, whilst the Eastern Antarctic Peninsula Abstract Introduction and James Ross Island have a polar continental climate, dominated by the Weddell Sea (Martin and Peel, 1978; Vaughan et al., 2003). The western coast of the Antarctic Conclusions References ◦ 15 Peninsula is therefore typically 7 C warmer than the eastern coast. These differences are further exacerbated by the different sea-ice regimes in the Bellingshausen and Tables Figures Weddell seas, with the Weddell Sea being sea-ice bound for much of the year (King et al., 2003). J I Climate records from the South Orkney Islands suggest that regional warming prob- J I 20 ably began in the 1930s (Vaughan et al., 2003). The greatest warming rates are in the east (at Marambio and Esperanza stations; cf. Fig. 1), and the smallest on the Back Close northwest coast. The most pronounced warming is in the winter months, and is related Full Screen / Esc to changes in atmospheric circulation, sea ice extent and ocean processes (Stastna, 2010). The Antarctic Oscillation represents the periodic strengthening and weakening Printer-friendly Version 25 of the belt of tropospheric westerlies that surround Antarctica (van den Broeke and van Lipzig, 2004). A strengthening of this circumpolar vortex results in an asymmetric sur- Interactive Discussion face pattern change, with pressure falling over Marie Byrd Land. This pressure pattern causes northerly flow anomalies, which in turn produce cooling over East Antarctica 3545 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion and warming over the Antarctic Peninsula. Decreased sea ice in the Bellingshausen Sea enhances warming over the Western Peninsula and the Weddell Sea. This is as- TCD sociated with decreases in precipitation over the South-Western Peninsula (van den 5, 3541–3594, 2011 Broeke and van Lipzig, 2004), but the Western Peninsula in general has the greatest 5 precipitation rates in Antarctica, typically 3–4 times that of any other part of the conti- nent (van Lipzig et al., 2004). Since the 1950s, the Antarctic Circumpolar Current has Glacier inventory and warmed by 0.2 ◦C, with the warming greatest near the surface (Gille, 2008), and waters glacier change to the west of the Antarctic Peninsula have warmed very rapidly (Turner et al., 2005; 1988–2009 Mayewski et al., 2009). B. J. Davies et al.

10 2.2 Contemporary glaciology

The Antarctic Peninsula Ice Sheet is typically 500 m thick over Trinity Peninsula, and Title Page its central plateau glaciers attain altitudes of over 1600 m a.s.l. along its central spine Abstract Introduction (Fig. 1). Trinity Peninsula outlet glaciers flow predominantly east and west, perpendic- ular to the Peninsula spine (Heroy and Anderson, 2005). On the eastern flank many Conclusions References 15 outlet glaciers terminate in floating or partly floating tongues. The North-Western Trinity Peninsula coastline mainly comprises grounded ice cliffs with the floating ice margins Tables Figures of a few small ice shelves and numerous small glaciers (Ferrigno et al., 2006). Currently, 80 % of James Ross Island is ice-covered (Rabassa et al., 1982), with J I the remainder comprising rock or Quaternary sediments with perennial permafrost J I 20 (Fukuda et al., 1992). The island is bounded to the Southwest, South and East by high cliffs and valley glaciers, and the ice cap drains over the cliffs into outlet glaciers, Back Close principally via avalanches and ice falls (Skvarca et al., 1995). The bedrock structure Full Screen / Esc of resistant volcanic rocks overlying soft Cretaceous sediments (Smellie et al., 2008; Hambrey et al., 2008) fosters the development of elongate, over-deepened cirques, Printer-friendly Version 25 with steep or near vertical back walls up to 800 m high. Vega Island is dominated by two plateau ice caps that feed numerous small tidewater glaciers. The ice-free area Interactive Discussion (approximately 34 %) is dominated by permafrost processes. Snow Hill Island, Corry Island and Eagle Island (Fig. 1) are dominated by large marine-terminating glaciers. 3546 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Snow Hill Island has extensive floating margins. Retreating tidewater termini have been mapped for the entire Trinity Peninsula, with TCD outlet glaciers on James Ross Island showing large reductions in area since the 1940s 5, 3541–3594, 2011 (Ferrigno et al., 2006). PGIS was connected to Larsen Ice Shelf until 1957/58 (Cook 5 and Vaughan, 2010). The northernmost ice shelf on the Eastern Antarctic Peninsula, it was the first to show signs of retreat (Ferrigno et al., 2006), and rapidly disintegrated in Glacier inventory and 1995 (Skvarca et al., 1995; Cooper, 1997), followed by the thinning, acceleration and glacier change rapid recession of the former ice shelf feeding glaciers (Rau et al., 2004; Glasser et al., 1988–2009 2011). During the later twentieth century, most glaciers on James Ross Island and B. J. Davies et al. 10 North-Eastern Antarctic Peninsula experienced rapid recession and calving, with the strongest evidence of recession in the northernmost parts. This is generally attributed to prevailing climatic warming (Vaughan et al., 2003; Rau et al., 2004). An average Title Page retreat rate of the James Ross Island glaciers of 1.8 km2 a−1 from 1975–1988 (Skvarca 2 −1 et al., 1995) doubled after the disintegration of PGIS, to 3.8 km a between 1988 and Abstract Introduction 15 2001 (Rau et al., 2004). Although Skvarca et al. (1995) noticed no dramatic change for small land-based glaciers from 1977 to 1988, retreat was observed from 1988 to 2001 Conclusions References

(Skvarca et al., 1995; Skvarca and De Angelis, 2003). Tables Figures

3 Data sources and methods J I

3.1 2009 glacier inventory J I Back Close 20 3.1.1 Data sources Full Screen / Esc This inventory is a snapshot of the glaciers on Trinity Peninsula, James Ross Is- land, Snow Hill Island and Vega Island in 2009. This data has been made avail- Printer-friendly Version able for download from the GLIMS geodatabase. Our methods conform to those set out by the GLIMS programme (Racoviteanu et al., 2009), and are given in full Interactive Discussion 25 in the Supplement. Mapping was conducted in ArcGIS 9.3 from interpretation of 2009

3547 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion ASTER images (Table 1 and Supplement). The geographical area mapped was limited by the availability of satellite imagery). The Antarctic Digital Database (ADD, TCD http://www.add.scar.org:8080/add/) Coastal Change dataset (from Cook et al., 2005) 5, 3541–3594, 2011 was used to provide additional data where the ice margin was difficult to map (e.g., 5 because of high cloud cover). Topographic elevation data and contours were derived from the 2006 SPIRIT Digital Elevation Model (DEM) (Table 1). Ground-control points Glacier inventory and were not necessary since accurate geolocation of the SPOT-5 images is possible. Each glacier change pixel in a SPOT-5 image can be located on the ground to ±25 m at the 66 % confidence 1988–2009 interval, although errors may be larger in areas of flat glacier ice (Reinartz et al., 2006; B. J. Davies et al. 10 Berthier et al., 2007; Korona et al., 2009). Glacier names and numbers were taken from previous glacier inventories and published maps (Rabassa et al., 1982; British Antarctic Survey, 1995, 2010; Czech Geological Survey, 2009). Title Page

3.1.2 Error estimation Abstract Introduction

Sources of uncertainty and mitigation strategies are summarised in Table 2. The Conclusions References 15 largest errors in glacier drainage basin delineation are derived from interpreter error of ice-divide identification and mapping. DEM quality in areas of flat white ice also Tables Figures limits the accuracy of ice divide mapping. ASTER Level 1B images are pre-processed but were co-registered to the SPOT-5 images to reduce errors. Calculation of area is J I limited by the pixel resolution of the dataset (i.e. ±15 m for ASTER images). Mapping J I 20 was estimated to be accurate to within 3 pixels (i.e. 45 m). A buffer of 22.5 m width was therefore placed either side of each glacier polygon, providing a minimum and maxi- Back Close mum estimate of size and a total error margin equivalent to 3 pixels. There may also be Full Screen / Esc an error in ASTER co-registration (Granshaw and Fountain, 2006); but this is assumed to be within the mapping limits. Printer-friendly Version

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3548 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 3.1.3 Drainage basin delineation TCD Automated methods for large-scale inventories can be used to map large regions quickly (e.g., Svoboda and Paul, 2009; Bolch et al., 2010), but they do not allow such 5, 3541–3594, 2011 high detail in digitisation. For this reason, we used manual digitisation to establish 5 glacier polygons in our high-resolution study of a small region, following guidelines set Glacier inventory and out by the GLIMS programme (refer to Supplement). A glacier polygon is a coherent glacier change body of ice that includes all tributaries and connected feeders, and excludes exposed 1988–2009 ground and nunataks (Racoviteanu et al., 2009; Raup and Khalsa, 2010). On James Ross Island many glaciers have well defined cirques, but the plateau above them was B. J. Davies et al. 10 included in their polygons (Fig. 1); this is because ice situated above the cliff-backed bergschrund contributes snow and ice through frequent avalanches and creep flow to the glacier. Title Page

Abstract Introduction 3.1.4 Attribute data for glacier drainage basins Conclusions References Attribute information determined for each glacier polygon comprises Area, Length, Co- 15 ordinates, Name (if published), Glacier ID (e.g., GAP17 or GIJR65, standing for Glacier Tables Figures Antarctic Peninsula and Glacier James Ross Island, respectively; these conform where appropriate to previous inventories), GLIMS ID, Elevation, Width of calving front, Date J I of scene acquisition, Satellite, Tongue (grounded, floating, land-terminating), Primary classification, Form, Frontal characteristics, Moraines, Debris on tongue, Remarks, J I 20 Slope, Aspect, ELA and Hypsometry, in addition to notes on geomorphology and Back Close glaciology (cf., Rau et al., 2005; Raup et al., 2007a,b; Racoviteanu et al., 2009; Paul et al., 2010; Raup and Khalsa, 2010). Form, Primary Classification, Frontal Character- Full Screen / Esc istics and Remarks are geomorphological descriptors that provide detailed information on the glaciers shape, terminus and classification (e.g., cirque, niche, outlet, valley Printer-friendly Version 25 glaciers) that correspond to GLIMS guidelines (Rau et al., 2005; Paul et al., 2010). Interactive Discussion In the Tongue parameter, glaciers were categorised as floating, partially floating, grounded or land-terminating. Land-terminating glaciers are relatively few in Antarctica, 3549 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion but as their recession is controlled more directly by changes in atmospheric temperature and precipitation than marine-terminating glaciers, they can be a sensitive in- TCD dicator of climate change (Oerlemans, 2005; Carrivick et al., 2011). The nature of 5, 3541–3594, 2011 the marine-terminating glacier tongue has important implications for oceanographic 5 and glaciological applications, but the grounding zone can only be accurately located with detailed geophysical surveys (Brunt et al., 2010), which are impractical for glacial Glacier inventory and inventories. However, the floating tongues of marine-terminating glaciers typically glacier change have several visual characteristics in common: a pronounced break in slope at the 1988–2009 grounding-line, an irregular, heavily crevassed and convex calving front, a flat long pro- B. J. Davies et al. 10 file, an irregular margin, and occasional large rifts. Alternatively, grounded tidewater glaciers are typically characterised by a concave calving front, a steadily dipping long profile, and have no clear break in slope (Dahl and Nesje, 1992; Scambos et al., 2004; Title Page Reinartz et al., 2006; Lambrecht et al., 2007; Fricker et al., 2009). Marine-terminating glaciers that exhibit a combination of these characteristics are defined as partially float- Abstract Introduction 15 ing, where either it is difficult to determine whether a glacier is floating or not, or where the glacier may be grounded at the lateral margins but floating in the centre of the Conclusions References

calving margin. Tables Figures Data were automatically derived in the GIS for minimum (HMIN), maximum (HMAX), mean (HMEAN) and median (HMEDIAN) elevation using the 2006 SPIRIT DEM. Elevation J I 20 data are unavailable for GAP40, GAP43 and glaciers north of GAP34 because of the geographical limits of the SPIRIT DEM. Values for mean slope and aspect were also J I calculated for each glacier polygon using the 2006 SPIRIT DEM (refer to Supplement). Back Close Aspect and slope are useful data for modelling purposes (Paul et al., 2010), and mean slope can be used as a proxy for ice thickness. Full Screen / Esc

25 3.1.5 Glacier hypsometry Printer-friendly Version

Glacier hypsometry is the distribution of glacier surface area with altitude, and is a ma- Interactive Discussion jor control on mass balance, as it strongly determines the accumulation area ratio (AAR) of a glacier. It is dependent on valley shape, topographic relief and glacier 3550 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion depth. When the ELA of a glacier changes, for example due to climate change, the extent of the impact on the glacier relies on the glacier hypsometry (Furbish and Andrews, TCD 1984). Faster rates of accumulation area loss during climatically-driven ELA rise will 5, 3541–3594, 2011 result in increased glacier recession. Glacier hypsometric curves were calculated by 2 5 masking 54 glacier polygons (i.e. those over 40 km ; all tidewater outlet glaciers) with the SPIRIT DEM, and the area in each 100 m elevation bin was calculated. Hypso- Glacier inventory and metric curves of cumulative area (km2) could then be plotted for the largest glaciers. glacier change A single Hypsometric Index (HI) (equivalent to “altitude skew”) was calculated for each 1988–2009 glacier polygon using the equation below, originally presented by Jiskoot et al. (2009), B. J. Davies et al. 10 where H −H −1 HI = median max , and if 0 < HI < 1, then HI = Hmedian −Hmin HI Title Page

3.1.6 Equilibrium line altitude derivation Abstract Introduction

In a glacier inventory, an estimation of the mean long-term ELA is considered to be vi- Conclusions References

tal, because it divides a glacier into ablation and accumulation areas. If air temperature Tables Figures 15 rises and/or if there is declining effective accumulation, mass balance will decline and the ELA will rise. ELAs have considerable inter-annual variability, with positive and negative mass balances from one year to the next (e.g., Carrivick and Chase, 2011). The J I long-term ELA is best determined by a programme of mass-balance measurements J I over several years (Braithwaite and Raper, 2009). However, field programmes are time Back Close 20 consuming and expensive and the Northern Antarctic Peninsula region is very difficult to access. Indeed, only one mass-balance investigation has been published for the Full Screen / Esc study area (Skvarca et al., 2004). However, there are a wide range of remote methods

for calculating glacier ELA (e.g., Carrivick and Brewer, 2004). In this study, ﬁve diﬀerent Printer-friendly Version long-term ELA derivation methods were applied (summarised in the Supplement and 25 in Table 4). Interactive Discussion

3551 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 3.2 Calculation of glacier change 1988 – 1997 – 2001 – 2009 TCD Assuming no migration of ice divides, and using the datasets named in Table 1 and in the Supplement, the extent and length of each glacier was also mapped for 1988 5, 3541–3594, 2011 and 2001. The ice front positions available in the ADD (from Cook et al., 2005) were 5 used to map ice extents in 1997. However, these data were only available for a limited Glacier inventory and number of tidewater glaciers. These time slices effectively capture the periods before, glacier change during and after ice-shelf collapse. The difference in area of each glacier polygon for 1988–2009 each time slice allowed calculation of area lost and rates of recession. Annual rates of glacier recession were calculated for each period. In subsequent analyses, glacier B. J. Davies et al. 10 surface areas that changed less than the calculated mapping error were classified as “stationary”. “Shrinkage” indicates a loss of surface area. Title Page

4 2009 Glacier inventory results Abstract Introduction

Conclusions References 4.1 Glacier size and elevation Tables Figures In 2009, the Northern Antarctic Peninsula region had 194 individual glaciers that cov- 2 15 ered a total area of 8140 ± 262 km (Fig. 1; Table 5; raw data available for download J I from GLIMS; www.glims.org). Trinity Peninsula was 95 % glacierised with 62 glaciers 2 covering 5827 ± 154 km (Table 5), which included the largest glaciers on the North- J I ern Antarctic Peninsula with 20 glaciers > 100 km2. James Ross Island was 75 % Back Close glacierised, which is a reduction of 5 % since the survey in 1977 (Rabassa et al., 1982). 20 Our inventory identified 104 glaciers on James Ross Island, whereas the original 1977 Full Screen / Esc survey identified 138. This difference is because of the significantly different approach used to map the glaciers (using ice divides and flow unit boundaries to delimit glacier Printer-friendly Version polygons). Many smaller glaciers or possibly snow patches mapped by Rabassa et al. (1982) are no longer discernible. While we attempted to follow the nomenclature used Interactive Discussion 25 by Rabassa et al. (1982) as far as possible to facilitate data comparisons, it was not

3552 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion possible in all cases, either because a glacier was not visible, had retreated and divided into two separate ice masses, or because two or more polygons were merged TCD together in line with the structural glaciological and ice divide mapping. Vega Island 5, 3541–3594, 2011 was 66 % glacierised with four plateau ice caps with nunataks dissecting catchments 2 5 into 11 outlet glaciers. A total of 24 glaciers covered 168 ± 15 km . Snow Hill Island had one large ice cap covering 326±3.6 km2, and was 96 % glacierised. Glacier inventory and The mean elevation of glaciers was skewed towards glaciers in the 200–300 m a.s.l. glacier change bin (Fig. 3a). A small number of glaciers over 100 km2 account for most of the 1988–2009 glacierised area (Fig. 3b). As the total area of glaciers in the size class 0.1–0.5 km2 is 2 B. J. Davies et al. 10 only 3 km , the underestimate of glacierised area caused by having a minimum glacier size of 0.1 km2 is likely to be insigniﬁcant and certainly considerably less than 3 km2. HMEAN of glaciers on Trinity Peninsula peaked at 400 m a.s.l., reﬂecting its high moun- Title Page tain chain. James Ross Island had the highest number of glaciers with mean elevations above 200 m. There was a strong correlation of glacier length and maximum elevation Abstract Introduction 2 15 (r = 0.8; Fig. 3c), and a rather weaker correlation between log glacier area and elevation (r2 = 0.5; Fig. 3d; Table 3). There is a weak relationship with log glacier area, Conclusions References

HMEAN and slope (Fig. 3e,f) and between glacier length and slope (Table 3). In general, Tables Figures longer glaciers had a lower slope, with large low-angled ablation areas.

4.2 Glacier form and classiﬁcation J I

J I 20 Outlet or valley glaciers drain the large plateau ice caps that rest on the Trinity Penin- sula mountain chain (Table 6). Almost all the glaciers on Trinity Peninsula calve into the Back Close ocean. Of these calving glaciers, 10 had floating and 20 had partially floating termini. Full Screen / Esc James Ross Island had 16 glaciers with floating termini (Fig. 4a), 48 land-terminating glaciers and one lacustrine glacier (GIJR86; Table 6). James Ross Island also had 17 Printer-friendly Version 25 out of the 18 small alpine glaciers, which were mostly cirque or small valley glaciers, and the few glacieret and snowfield remnant glaciers in the study area. The remaining Interactive Discussion islands were characterised by small ice caps. Snow Hill Island ice cap has extensive floating margins. 3553 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 4.3 Equilibrium line altitudes TCD There is a very strong regressionc between ELAMEDIAN, ELAAAR and ELATHAR (Fig. 3h; 5, 3541–3594, 2011 Tables 3, 4 and 5). However, there is considerable scatter in ELAHESS and ELATSL and they show no correlation with ELAMEDIAN (Table 5; p values of 0.4 and 0.3, re- 5 spectively). The large standard error indicates little regional consistency in ELATSL. Glacier inventory and Mapping snowlines on Trinity Peninsula is likely to produce substantially different re- glacier change sults to other methods, as the strong east-west precipitation gradient on Trinity Penin- 1988–2009 sula results in snow lines close to sea level on the western coast, and snow lines at 300 to 400 m a.s.l. on the Eastern Peninsula. Strong winds also affect the distribu- B. J. Davies et al. 10 tion of snow at the end of the ablation season. In addition, it was difficult to achieve total scene coverage for each year mapped, and there are large gaps in the data. These polar glaciers are characterised by complex accumulation zones with patches Title Page

of accumulation and ablation separated by areas of superimposed ice (Skvarca et al., Abstract Introduction 2004), making accurate remote mapping of transient snow lines difficult. Furthermore, 15 mapping of snowlines may occur either just after or just before a snowfall event. As Conclusions References snowfalls occur throughout the summer season in polar regions, this is likely to further Tables Figures skew results. Because of these inherent methodological difficulties, large data gaps, large inter-annual scatter and low correlation, ELATSL was henceforth excluded from J I the analysis. ELAHESS was also excluded from further analysis as it is likely to only 20 be applicable to 13 land-terminating glaciers (not being generally applicable to marine- J I terminating glaciers, glaciers with ice falls, glaciers with complex or compound cirques, or glaciers terminating in steep cliffs; Jiskoot et al., 2009), and there was again large Back Close

scatter and low correlation (Fig. 3h). Full Screen / Esc ELAMEAN is therefore the average of ELAMEDIAN, ELAAAR and ELATHAR. However, 25 the calculated ELA for each glacier must necessarily be treated with caution, as MEAN Printer-friendly Version it is entirely derived from the altitudinal range and hypsometric curves of the glaciers, has not been checked against mass-balance data, and does not take into account Interactive Discussion east-west orographic precipitation and wind variations. Standard deviations range from

3554 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion < 5 m to > 500 m, illustrating the difficulty in obtaining a meaningful parameter from topographical data alone. TCD Our topographical ELA predictions can be compared with previous mass balance 5, 3541–3594, 2011 studies carried out on GIV09, Vega Island (Glaciar Bahia del Diablo; Skvarca et al., 5 2004). GIV09 was, at time of publication, experiencing a negative mass balance, thinning and frontal retreat. Skvarca et al. (2004) found the equilibrium line of GIV09 Glacier inventory and difficult to determine, as it had an accumulation area with zones of snow accumulation glacier change and ablation, separated by zones of superimposed ice. The altitude of zero mass bal- 1988–2009 ance was estimated by Skvarca et al. (2004) to be 400 m a.s.l. This is much higher B. J. Davies et al. 10 than our remotely mapped ELAMEAN of 245 ± 92 m a.s.l. It is thus possible that our predicted ELAMEAN is an underestimate, but it is impossible to verify without further spatially-distributed mass-balance data. Title Page Figure 4b shows the distribution of ELA over the study region. The subdued topography on Ulu Peninsula, James Ross Island, results in low ELAMEAN of around 100 m a.s.l. Abstract Introduction 15 However, the glaciers that have accumulation areas on the Mount Haddington Ice Cap Conclusions References can have ELAMEAN > 800 m a.s.l. ELAMEAN on Trinity Peninsula are generally around 500 to 600 m a.s.l., with the exception of GAP60 and 61, which have ELAMEAN of Tables Figures 1194±727 and 1265±787 m a.s.l., respectively. The range of values may be less for land-terminating simple-basin glaciers, whose size may be more closely determined by J I 20 climatic factors. For example, GIJR103, a grounded valley glacier with a simple basin, has an ELAMEAN of 87 ± 1 m a.s.l. The range of errors for simple basin glaciers with J I floating tongues (such as, for example, GIJR64, ELAMEAN 909±432 m a.s.l.) may be Back Close because of their large low-lying ablation areas. Full Screen / Esc 4.4 Glacier aspect

Printer-friendly Version 25 Mean glacier aspect is summarised in Fig. 4c,e. There is no correlation with elevation (Fig. 3i; Table 5). The aspect of a glacier controls receipt of solar insolation, as Interactive Discussion well as influencing the drifting of snow through persistent winds. Most glaciers display asymmetry over their surface area, which results, for example, in a strong northeast to 3555 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion west-facing preferred glacier aspect on Trinity Peninsula (Fig. 4c). On James Ross Is- land, there is a preference for northwest-facing aspects. Aspects on Vega Island trend TCD largely southeast and northwest, reflecting the west-east axis of the island. 5, 3541–3594, 2011 4.5 Glacier hypsometry Glacier inventory and 5 The hypsometric index (HI) of all glaciers was calculated and glaciers were divided into glacier change > . < . five categories from HI 1 5 (very bottom heavy) to HI −1 5 (very top heavy) (Ta- 1988–2009 ble 7; see Jiskoot et al., 2009). There was considerable inter-catchment variability in glacier shape and elevation distributions. Over half (35) of the large outlet glaciers on B. J. Davies et al. Trinity Peninsula were very bottom-heavy, with large low-lying areas below the median 10 altitude (Fig. 4d,f). Exceptions are a few glaciers that terminate within narrow bays (e.g., GAP13, GAP17). However, on the west coast of Trinity Peninsula, glaciers are Title Page more equi-dimensional or top-heavy. Glaciers that were formerly tributaries to PGIS Abstract Introduction were large with relatively small accumulation areas. The remaining glaciers on East- ern Trinity Peninsula were generally bottom-heavy, for example, GAP34, GAP31 and Conclusions References 15 GAP20. On James Ross Island, the low-lying topography of Ulu Peninsula resulted in bottom- Tables Figures heavy outlet glaciers draining Dobson Dome (Fig. 4d,f), but the large Mount Haddington Ice Cap contained largely top-heavy glaciers, such as GIJR115 and GIJR61. The long- J I profiles of tidewater outlet glaciers draining the Mount Haddington Ice Cap are typified J I 20 by sharp changes in slope angle in ice falls at their cirque headwalls, followed by large, low-lying and relatively flat partly floating or floating glacier tongues (Fig. 4g). Back Close In Fig. 5, example normalised hypsometric curves derived from the 2006 SPIRIT Full Screen / Esc DEM are presented and the normalised ELAMEAN has been plotted, which generally fell at about 60 % of the accumulation area. ELAMEAN, which is closely related to me- Printer-friendly Version 25 dian elevation (which was used in the ELA calculation; see Sect. 3.1.5), is a control on glacier recession. The examples in Fig. 5 illustrate the difference between bottom- Interactive Discussion heavy (GAP12, GAP45), equi-dimensional (GAP14, GAP53) and top-heavy (GAP13, GAP60) glaciers. Glaciers with a small accumulation area could be more sensitive 3556 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion to climate change if the ELA rises and allows a large additional area to be an ablation zone, especially if the ELA rises above the new median altitude. Comparing the TCD hypsometric curves in Fig. 5 with the long profiles presented in Fig. 4g, it is obvious 5, 3541–3594, 2011 that the low-lying floating tongues of the Mount Haddington Ice Cap outlet glaciers re- 5 sult in large, low-lying ablation areas that may be vulnerable climate change (rises in temperature or decreases in effective precipitation). Glacier inventory and glacier change 1988–2009 5 Glacier change results B. J. Davies et al. 5.1 Change in glacierised area

On Fig. 1, the extent of glaciers in 1988, 1997, 2001 and 2009 is shown, including the Title Page 10 former PGIS. For purposes of data summary, where no data are available for a particular year, it is assumed that the area is the same as in the previous analysis from which Abstract Introduction data is available; however, the values are blank in the ﬁgures and Supplement when Conclusions References there is no new data available. The total area given is therefore a minimum value. There was only satellite coverage of all three years (1988, 2001 and 2009) for 178 Tables Figures 15 glaciers. Full rates of glacier recession (with errors) are presented in the Supplement.

In the study region, 90 % of glaciers receded in the period 1988–2001, and 79 % J I shrank from 2001–2009 (Table 8). On Trinity Peninsula and Vega Islands, advances only occurred from 1988–2001 in two glaciers (GAP10 by 0.73 ± 0.4 km2; GIV05 J I 2 2 by 0.02 ± 0.01 km ). On James Ross Island, GIJR54 (0.06 ± 0.04 km ), GIJR71 Back Close 2 2 20 (0.10 ± 0.05 km ) and GIJR90 (0.22 ± 0.2 km ) advanced from 1988–2001. Diﬀerent glaciers had small advances from 2001–2009 (GIJR124 by 0.46 ± 0.12 km2; GIJR72 Full Screen / Esc by 1.11 ± 0.15 km2; and GIJR78 by 0.10 ± 0.03 km2). It is noteworthy that diﬀerent glaciers advanced in each time period, and that the number of advancing glaciers Printer-friendly Version has decreased since 2001; this variance highlights the individual dynamics of these Interactive Discussion 25 glaciers. Most of the advancing glaciers were marine-terminating outlet glaciers, which may have a non-linear response to atmospheric forcing. 3557 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion The 61 tidewater glaciers and single land-terminating glacier on Trinity Peninsula cover 5827.3 ± 153.9 km2, and from 1988–2001, lost 727.8 km2, equivalent to an TCD average recession rate of 56 km2 a−1. These glaciers then retreated at a rate of 5, 3541–3594, 2011 16.8 km2 a−1 in the 8 yr from 2001–2009. The 104 glaciers on James Ross Island 2 2 5 lost 290±15.2 km of surface area between 1988 and 2001, and 121.9±15.2 km between 2001 and 2009 (Table 9). This equates to an overall retreat rate on James Ross Glacier inventory and Island of 22.3 km2 a−1 over the 13 yr from 1988–2001, and 15.1 km2 a−1 over the 8 yr glacier change from 2001–2009. Two small glaciers (GIJR56 and GIJR30) on James Ross Island dis- 1988–2009 appeared between 1988 and 2009. The majority of the area lost on James Ross Island B. J. Davies et al. 10 is accounted for by the disintegration of PGIS in 1995. For most glaciers, the annual rate of retreat has accelerated since 2001, with those on Eastern Antarctic Peninsula and James Ross Island exhibiting particularly rapid recession. Title Page

5.2 Land-terminating glaciers Abstract Introduction The recession of land-terminating glaciers is of particular interest because their activity Conclusions References 15 is directly related to atmospheric and climatic changes, and these glaciers are scarce on the Antarctic Peninsula (Skvarca and De Angelis, 2003). In the study region, they Tables Figures are generally small; most are less than 1 km2, and so would be expected to react

fastest to external forcings (Paul et al., 2004), although this can vary regionally (Raper J I and Braithewaite, 2009). Response times are also determined by slope and mass 20 balance gradient (Oerlemans, 2005); Fig. 3f illustrates that there is a weak negative J I

relationship between glacier area and mean slope, and that smaller glaciers are often Back Close steeper (p value of 0.001). The seven land-terminating glaciers on Vega Island have all retreated since 1988 Full Screen / Esc (Fig. 6a,b). However, there has been little shrinkage in these glaciers since 2001. Most 25 glacier retreat on Vega Island occurred in the period 1988–2001, with the glaciers Printer-friendly Version generally shrinking by 2 to 7 % (Fig. 6a). The majority of the 48 land-terminating glaciers on James Ross Island are < 1 km2, but the shrinkage of these glaciers is Interactive Discussion highly variable. For glaciers < 1 km2, the percentage shrinkage varies from 0 to 66 % 3558 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion (Fig. 6c,d). Glaciers < 3 km2 also show highly variable patterns of shrinkage, from 0 to 35 % (Fig. 7e,f). Overall, the largest reaction to climate warming in the Antarctic Penin- TCD 2 sula is in small land-terminating mountain glaciers that are less than 1 km . Indeed, 5, 3541–3594, 2011 there is a weak regression between initial glacier size (1988) and total glacier area lost 2 5 (1988–2009; r = 0.19; Fig. 6g; Table 5). From previous inventories, it is evident that most of the margins land-terminating Glacier inventory and glaciers in the Northern Antarctic Peninsula region were stationary until 2001–2002, glacier change whereupon shrinkage was widely observed (Rau et al., 2004). Our study shows that 1988–2009 glacier recession has continued since this period. However, the largest areal changes B. J. Davies et al. 10 were observed in the period 1988–2001. Figure 6h shows that the largest annual rates of recession on James Ross Island were between 1988–2001, with only limited reces-

sion of land-terminating glaciers after this period. This supports initial observations by Title Page Rau et al. (2004). In the period 1975–1988, ﬁve land-terminating glaciers were found to be retreating; in the period 1988–2002, 17 out of 21 land-terminating glaciers were Abstract Introduction 15 retreating. Of the 48 land-terminating glaciers we mapped on the island, 36 out of Conclusions References the 48 mapped land-terminating glaciers had retreated from 1988–2001. In the period 2001–2009, 15 glaciers had retreated. In both time periods, the remaining glaciers Tables Figures were stationary and none had advanced.

J I 5.3 Marine-terminating glaciers 2 J I 20 In total, glaciers receded by 1319.5±395.6 km in the Northern Antarctic Peninsula be- 2 tween 1988 and 2009. Of this areal decline, 70 % (927.7±395.6 km ) occurred prior to Back Close 1997 with the disintegration of PGIS in 1995 (Table 8). However, glacier recession has continued, with 274 ± 49.1 km2 lost since 2001; this is equivalent to a total recession Full Screen / Esc rate of 30.4±1.0 km2 a−1 since 2001 (error estimated probabilistically). On Vega Island, Printer-friendly Version 25 Glaciar Bahia del Diablo (GIV09; Fig. 1) was relatively stable in the period 1982–1985, but showed considerable thinning from 1985–1998, with an average surface lowering Interactive Discussion of 13.1 m (Skvarca and De Angelis, 2003). Our study of GIV09 from 1988–2009 shows continued shrinkage (0.5 km2) since 2001. 3559 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion The highest annual rate of recession was reached in the period 1988–1997, when Sjogren¨ Glacier (GAP12; Fig. 1) receded at 17.7 km2 a−1. Sjogren¨ Glacier was a major TCD contributor to the ice shelf, and lost 1.2 km2 a−1 in the period 1997–2001. The an- 5, 3541–3594, 2011 nual rate of recession then accelerated, reaching 2.4 km2 a−1 in the period 2001–2009. 2 −1 5 GAP15 was also a major contributor to PGIS and receded at a rate of 13.8 km a from 1988 to 1997, 0.6 km2 a−1 from 1997 to 2001, and 0.3 km2 a−1 from 2001 to 2009. Glacier inventory and There is wide variety in rates of glacier recession; GAP05 is the glacier with the high- glacier change est annual rate of recession that did not feed PGIS. GAP05 lost 9.1 % of its total area 1988–2009 in the period 1988–2009, with recession rates of 0.4 km2 a−1 from 1988 to 2001 and 2 −1 B. J. Davies et al. 10 1.0 km a from 2001 to 2009. The glaciers of Western Trinity Peninsula have had very low rates of recession or have remained stationary. The recession of glaciers (decrease in glacier length) was greatest for ice-shelf trib- Title Page utary glaciers. For example, Sjogren¨ Glacier (GAP12) retreated 33 km from 1988 to 2001 and 7.1 km from 2001 to 2009 (Fig. 7a), and GAP01 to GAP14 had faster annual Abstract Introduction 15 rates of glacier retreat both from 1988–2001 and 2001–2009. The change in length for non-ice-shelf tributary glaciers is small by comparison, but they generally had faster Conclusions References

rates of retreat after 2001. Figure 7c,d shows little correlation between 2009 glacier Tables Figures length, width of calving tongue and rates of glacier retreat (cf. Table 3), but emphasise that rates of length change were faster 1988–2001. Even after 2001, the fastest an- J I 20 nual rates of length change are in former PGIS tributary glaciers (Fig. 7b). Glaciers on Western Trinity Peninsula in general show less change in glacier length and area. J I Analysing the rates of recession for the glaciers that fed PGIS in more detail, Fig. 7c Back Close highlights the diﬀerence in GAP15, GAP14 and GAP12. It is apparent that most of the shrinkage of these three glaciers occurred before 1997, immediately preceding ice- Full Screen / Esc 25 shelf disintegration, with slower and steadier retreat thereafter. These areal losses are substantially larger than the mapped errors. The recession rate decreases after this, Printer-friendly Version with less areal loss. On the other hand, for glaciers on James Ross Island, in particular GIJR92 and GIJR90, which are situated in Rohss¨ Bay, the recession rate is fastest Interactive Discussion after 2001 (Fig. 7c).

3560 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 5.4 Spatial and temporal patterns of glacier change TCD On Trinity Peninsula, ice-shelf tributary glaciers retreated fastest overall and particularly rapidly from 1988–2001 (Fig. 8). Regions of exceptionally rapid glacier recession on 5, 3541–3594, 2011 Trinity Peninsula include Larsen Inlet, Sjogren¨ Inlet, Eyrie Bay and Duse Bay. Almost 5 all glaciers show signs of glacier recession; four glaciers on Trinity Peninsula advanced Glacier inventory and from 1988–2001 (Table 8), but after 2001 none have advanced more than the error glacier change margin. All advances were small and were subsumed by the overall recession from 1988–2009 1988 to 2009. There are fewer data available for Western Antarctic Peninsula, but shrinkage rates for the period 1988–2009 have remained low in that region (Fig. 9). B. J. Davies et al. 10 This contrasts with glaciers on North-Eastern Trinity Peninsula (Fig. 8a). Some ice-shelf tributary glaciers on James Ross Island also show small signs of advance during the period (Table 8). The remaining glaciers of Rohss¨ Bay experienced Title Page

enhanced drawdown and faster rates of annual recession after 2001. GIJR90 declined Abstract Introduction in area at a rate of 1.9 km2 a−1 from 2001–2009, when the ice shelf retreated beyond 15 the narrow pinning point at the head of Rohss¨ Bay, but the margin was stationary from Conclusions References 1988–2001. This is highlighted in Fig. 8d, which shows the diﬀerence in recession be- Tables Figures tween 1988–2001 and 2001–2009. These tidewater glaciers now no longer terminate in a discernible ice shelf, but calve directly into Rohss¨ Bay. Many large tidewater glaciers on James Ross Island suﬀered rapid areal decline J I 2 −1 2 −1 20 from 1988 to 2009 (e.g., GIJR108 [0.6 km a ], GIJR115 [0.5 km a ], and GIJR128 J I [0.4 km2 a−1] (Fig. 1)). There is strongly asynchronous behaviour (Fig. 8a). The glaciers of Croft Bay and GIJR72 [0.1 km2 a−1], in Holluschickie Bay, for example, de- Back Close

clined comparatively little. Variable rates of areal shrinkage are also noticeable around Full Screen / Esc Cape Broms of Southeast James Ross Island. In general, most glaciers retreated 25 faster from 1988–2001, with some exceptions around Rohss¨ Bay on James Ross Is- Printer-friendly Version land, Snow Hill Island and the Western Trinity Peninsula (Figs. 7 and 8d, Table 8). Interactive Discussion

3561 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 6 Discussion TCD 6.1 Comparison with previous inventories 5, 3541–3594, 2011 Our data support the general recessional trend reported in previous inventories (Rabassa et al., 1982; Skvarca et al., 1995; Rau et al., 2004). Our inventory shows Glacier inventory and 5 a continued and steadily increasing glacier recession since the first inventory 1977 (cf., 2 −1 glacier change Rabassa et al., 1982). Average retreat rates for James Ross Island were 1.8 km a in 1988–2009 the period 1975–1988, and 2.1 km2 a−1 in the period 1988–1993 (Skvarca et al., 1995; Rau et al., 2004). Our study indicates that glaciers on James Ross Island retreated B. J. Davies et al. at a rate of 22.3 km2 a−1 from 1988–2001, and 15.1 km2 a−1 from 2001–2009, indicat- 10 ing increased rates of recession immediately post ice-shelf disappearance but slower rates in the longer-term, which are presumably in response to continued atmospheric Title Page and sea surface temperature increases. Given the hypsometry of the large tidewater Abstract Introduction glaciers draining the Mount Haddington Ice Cap on James Ross Island, these retreat rates are likely to continue if atmospheric temperatures continue to rise. Conclusions References 15 Overall, recession rates across the Antarctic Peninsula are slowing, which may be as a result of tidewater glaciers reaching their grounding lines, and achieving increased Tables Figures frontal stability. In addition, reported mean annual air temperatures on Ulu Peninsula, ◦ ◦ James Ross Island, were −5 C from 1999 to 2004 (Sone et al., 2007) and −7.2 C from J I 2006 to 2009 (Laska et al., 2010), suggesting that a few particularly warm years may J I 20 have made a large difference to overall recession rates. Differences in inter-catchment recession rates may reflect variance in altitude, accumulation area, shifting ice divides, Back Close and non-linear tidewater glacier responses to oceanic and atmospheric forcing. Full Screen / Esc 6.2 Impact of the disintegration of Prince Gustav Ice Shelf Printer-friendly Version The remnant of PGIS in Rohss¨ Bay on James Ross Island (Fig. 1) dramatically disin- Interactive Discussion 25 tegrated after 2001. Small ice shelves are susceptible to small changes in temperature and mass balance of tributary glaciers (Glasser et al., 2011). The retreat of ice 3562 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion shelves from pinning points (such as Persson Island) can result in enhanced calving and rapid retreat. The acceleration of recession of the ice shelf in Rohss¨ Bay after TCD 2001 was therefore caused by ice-dynamical factors, exacerbated by continued atmo- 5, 3541–3594, 2011 spheric warming. Small amounts of growth in some ice-shelf glaciers was observed 5 from 1988 to 2001, which could be because of pinning against Persson Island and the mainland of James Ross Island, and structural and dynamic variations in ice-shelf con- Glacier inventory and figuration. However, this advance was subsumed by the overall large glacier shrinkage glacier change (cf. Fig. 8). In addition, up-glacier thinning may result in steepening, increased driving 1988–2009 stress, faster flow, and short-term advance (cf., Meier and Post, 1987). B. J. Davies et al. 10 The recession of marine-terminating glaciers in the Northern Antarctic Peninsula highlights some important trends. For glaciers feeding PGIS, rates of recession were highest during the period of ice-shelf disintegration. Ice-shelf removal can lead to Title Page the destabilisation of tributary glaciers, as ice shelves reduce longitudinal stresses and limit glacier motion upstream of the ice shelf (Rignot et al., 2004; Pritchard and Abstract Introduction 15 Vaughan, 2007; Hulbe et al., 2008). These tributary glaciers began to stabilise and reach a new dynamic equilibrium after 2001 and rates of recession began to reduce Conclusions References

once they become stabilised in their narrow fjords. Indeed, fjord geometry has previ- Tables Figures ously been observed to be a major control on tidewater glacier advance and recession rates (Meier and Post, 1987). After 2001, the region therefore entered a period of “nor- J I 20 mal” glacier recession. The Northern Antarctic Peninsula region has thus had three distinctive phases: 1988–1995, the stable ice-shelf period; 1995–2001, the period of J I ice-shelf disintegration and rapid readjustment of the ice-shelf tributary glaciers to new Back Close boundary conditions; and 2001–2009, when all glaciers are retreating in response to changes in atmospheric and oceanic temperatures. The more rapid recession of the Full Screen / Esc 25 ice-shelf tributary glaciers in Rohss¨ Bay since 2001 (Fig. 8c) is a response to the initial pinning of the ice-shelf post-break up in the mouth of Rohss¨ Bay. Structural glacio- Printer-friendly Version logical controls are therefore strongly inﬂuencing the patterns and rates of retreat of ﬂoating tongues following ice-shelf disintegration. Ice-margins stabilised after 2001 Interactive Discussion once the glaciers retreated to within their bays with shrinkage slowed as a result of

3563 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion enhanced back-stress and pinning against the fjord sides. The majority of the glacier ice lost on James Ross Island is accounted for by the dis- TCD integration of PGIS in 1995. For most remaining glaciers, recession rates were highest 5, 3541–3594, 2011 prior to 2001, with ice-shelf tributary glaciers on Eastern Trinity Peninsula exhibiting 5 particularly rapid recession. Western Trinity Peninsula glaciers had very low rates of recession or have remained unchanged. This differing regional response can probably Glacier inventory and be attributed to precipitation gradients, exacerbated by climatic warming and differen- glacier change tial wind patterns (cf., van Lipzig et al., 2004). As south-westerly winds blow across 1988–2009 the Antarctic Peninsula mountains, rising air precipitates moisture as snow in the west, B. J. Davies et al. 10 starving the east of precipitation (Aristarain et al., 1987; Vaughan et al., 2003). James Ross Island lies in the precipitation shadow of the Antarctic Peninsula. Higher air temperatures will have resulted in a rise in ELA; smaller accumulation areas mean that Title Page glaciers are less able to withstand precipitation starvation. Previous workers have hypothesised that the disintegration of the ice shelf may have Abstract Introduction 15 affected the regional climate (Rau et al., 2004). The response of land-terminating glaciers is particularly interesting, because on James Ross Island, these glaciers ex- Conclusions References

hibited their highest annual rates of retreat in the ice-shelf disintegration period. Land- Tables Figures terminating glaciers are directly inﬂuenced by climatic perturbations and their mass balances are therefore a sensitive indicator of climate variability (Oerlemans, 2005). J I 20 It therefore appears that the removal of the ice shelf changed the local climate and thus had a strong impact on the island’s glaciers. It has been suggested that ice-shelf J I break up would immediately aﬀect the climate system through the formation of deep Back Close water (Hulbe et al., 2004). The removal of the ice shelf would have raised local air temperatures through the availability of more ice-free water in summer. In addition, Full Screen / Esc 25 small glaciers on James Ross Island may be particularly susceptible to changes in local climate because of the large land area, which has a low albedo. Printer-friendly Version

Interactive Discussion

3564 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 6.3 Glacier hypsometry TCD Topography and hypsometry are important factors in inﬂuencing glacier mass balance, and may explain some of the inter-catchment variability in recession rates. Figure 8c 5, 3541–3594, 2011 shows GAP17 and GAP18 (both outlet tidewater glaciers) receding at diﬀerent rates. 5 GAP17 remained stationary during the period 2001–2009, whilst the adjacent GAP18 Glacier inventory and 2 −1 retreated at 0.2 ± 0.6 km a during the same interval. However, GAP17 has a very glacier change top-heavy HI index of −1.6, compared with 1.8 for GAP18 (cf. Fig. 5d). The more 1988–2009 stable glaciers on the Western Peninsula typically have equi-dimensional or top-heavy hypsometric curves (Figs. 4 and 5), which combined with high snowfalls (van Lipzig B. J. Davies et al. 10 et al., 2004), render them less susceptible to the changes in ELA brought about by changing atmospheric temperatures (cf., Jiskoot et al., 2009). These glaciers have accumulation areas situated at high altitudes, which contributes to their stability. The Title Page

hypsometric curves of these grounded tidewater glaciers indicate that they will retain Abstract Introduction large accumulation areas if future recession occurs and thus recession will be slow, 15 rendering them less sensitive to an upwards shift in the ELA. Conclusions References The outlet glaciers draining Mount Haddington Ice Cap typically have a large upland Tables Figures accumulation area on the ice cap, a steep icefall over cirque headwalls, and a very flat and low-lying partly floating or floating tongue. These attributes can be observed in the stepped hypsometric curves of GIJR123 and GIJR115 (Fig. 6). This unusual J I

20 glacier long proﬁle (Fig. 4g) is bedrock-controlled. Vertical joints in the hard Neogene J I basalts and hyaloclastites encourage the formation of steep cirque headwalls. The glaciers then erode a deep basin in the softer Cretaceous sandstone and mudstone Back Close

beneath, resulting in partly ﬂoating to ﬂoating glacier tongues. Rising sea levels would Full Screen / Esc encourage further grounding-line retreat.

Printer-friendly Version 25 6.4 Changes in equilibrium line altitude Interactive Discussion If atmospheric temperature rises over the Antarctic Peninsula continue at the current rate of 2.5 ◦C per 50 yr (Vaughan et al., 2003; IPCC, 2007), a rise of 2 ◦C could be 3565 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion reached in the Antarctic Peninsula region between the “present” and the year 2040. Given a calculated adiabatic lapse rate of −5.8 ◦C per 1000 m (Aristarain et al., 1987), TCD and assuming that the topographic ELA values calculated are representative of the 5, 3541–3594, 2011 current isoline of zero mass balance on these glaciers, an increase of 2 ◦C would raise 5 ELAs over the Northern Antarctic Peninsula by 345 m. This is illustrated as ELA2C on the hypsometric curves in Fig. 5, and it is immediately obvious that the diﬀerential Glacier inventory and hypsometry of the glaciers may be an important control on rates of recession in the glacier change future. Bottom-heavy glaciers with low-lying ELAMEAN values (such as GAP12) and 1988–2009 top-heavy glaciers with high ELAMEAN values (such as GAP13; Fig. 5) are most sensi- B. J. Davies et al. 10 tive to change. In general, however, the tidewater glaciers on Eastern Trinity Peninsula have large, high-elevation accumulation areas. Without a further strong perturbation to the prevailing climate, these large tidewater glaciers will most likely stabilise when Title Page they reach their grounding-lines. The ELA2C calculated for these glaciers (Fig. 5) in- ◦ dicates that even with a 2 C rise in temperature, glaciers will still retain accumulation Abstract Introduction 15 areas covering at least 40 % of the glacier surface, assuming that glacier hypsome- tries remain similar. The steady steep slopes on these glaciers also render them less Conclusions References

vulnerable; a rise in ELA does not expose a significantly larger area to ablation. Addi- Tables Figures tionally, as these glaciers retreat towards the grounding-line zones, ablation areas will decrease in size, resulting in a more stable mass balance. J I 20 The tidewater glaciers on James Ross Island are likely to be extremely vulnerable to a 345 m rise in ELA. GIJR27, for example, may be particularly vulnerable as this tidewa- J I ter glacier has a large, low-lying flat tongue, and ELA2C plots above the accumulation Back Close area. Other glaciers with low-lying tongues will have projected accumulation areas covering only 20–30 % of their area (e.g., GIJR72, GIJR115, GIJR128, GIJR136). These Full Screen / Esc 25 glaciers are likely to continue to retreat very rapidly. Furthermore, the large accumulation areas of glaciers on Mount Haddington Ice Cap are fairly flat. An increase in ELA Printer-friendly Version will result in rapid loss of accumulation area here. Interactive Discussion

3566 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 6.5 Oceanic temperatures and climate forcing TCD The calving ﬂux and recession of tidewater glaciers in the study region is likely to be largely controlled by non-linear glacier responses to changes in oceanic temper- 5, 3541–3594, 2011 atures as well as atmospheric temperature and precipitation gradients. Ocean tem- ◦ 5 peratures around the Western Antarctic Peninsula have risen by more than 1 C since Glacier inventory and 1951 (Gille, 2002, 2008; Meredith and King, 2005), driven by reduced sea-ice forma- glacier change tion and atmospheric warming. Changes in sea-surface temperatures (and sea ice 1988–2009 extent) may inﬂuence enhance bottom melting and thinning (Holland et al., 2010) and therefore propensity to calve (Benn et al., 2007a), thus accelerating terminus retreat. B. J. Davies et al. 10 Tensile strength of glacier ice decreases as ice becomes more temperate, resulting in increased calving rates (Powell, 1991). Furthermore, retreat of the terminus, as a result of increased calving, leads to larger up-glacier stretching rates, greater ice speeds Title Page

and glacier thinning, further exacerbating increased calving rates for tidewater glaciers Abstract Introduction (Meier and Post, 1987; van der Veen, 2002), and possibly contributing to short-term 15 small glacier advances. Conclusions References The observed asymmetry and variability in recession in tidewater glaciers may be Tables Figures explained by complex calving processes. The calving ﬂux of tidewater glaciers is controlled by crevasse depth, ice velocity, strain rates, ice thickness and water depth (Benn et al., 2007a). In grounded tidewater glaciers, terminus position may be controlled by J I

20 the local geometry of the fjord (van der Veen, 2002). Rapid recession of tidewater J I glaciers in the region is likely to be enhanced by the asymmetry of the calving ﬂux between advancing and retreating glaciers, with increased calving exacerbating the Back Close

recessional trends (Benn et al., 2007b). Full Screen / Esc

7 Conclusions Printer-friendly Version

Interactive Discussion 25 The Antarctic Peninsula is experiencing rapid atmospheric warming, which has resulted in the disintegration of many ice shelves (Scambos et al., 2003; Hulbe et al., 3567 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 2008; Glasser and Scambos, 2008; Cook and Vaughan, 2010). Numerous papers have documented the disintegration of those ice shelves, but this is the first to thor- TCD oughly and quantitatively investigate changes in all glaciers in the Trinity Peninsula 5, 3541–3594, 2011 region. We provide the first detailed inventory of 194 glaciers on Trinity Peninsula and 5 islands to the southeast, with detailed estimates of size, length, elevation ranges, ELA, slope, aspect, hypsometry, morphological descriptors, form and classification. These Glacier inventory and data will be invaluable to numerical modellers seeking to predict the future behaviour glacier change of this climatically sensitive region. The full glacier inventory is available for download 1988–2009 from GLIMS (www.glims.org). B. J. Davies et al. 10 We measured variability in glacier length and area changes on the Northern Antarc- tic Peninsula between 1988, 1997, 2001 and 2009. This inventory provides important data for monitoring glacier recession on the Antarctic Peninsula. Changes in glacier Title Page area and length presented in this tudy considerably extend the hitherto available geographical coverage and amount of detail available for understanding the impacts of Abstract Introduction 15 climate change on the cryosphere. Of the 194 glaciers surveyed, 90 % showed rapid retreat from 1988–2001 and 79 % Conclusions References

retreated from 2001–2009, although the rates and patterns of recession vary substan- Tables Figures tially. Overall, annual rates of recession were higher from 1988–2001 in tidewater and ice-shelf tributary glaciers. Some glaciers on Western Trinity Peninsula, glaciers in J I 20 Rohss¨ Bay on James Ross Island and Snow Hill Island retreated faster from 2001– 2009. Annual rates of recession in land-terminating glaciers were also higher from J I 1988–2001. Three distinct phases were observed: 1988–1997 (the ice-shelf and ice- Back Close shelf disintegration era); 1997–2001 (period of immediate adjustment); 2001–2009 (period of stabilisation and long-term adjustment to new dynamic equilibrium and general Full Screen / Esc 25 climate-driven recession). Total glacierised area in the Northern Antarctic Peninsula 2 −1 has declined at an average of 30.4±0.99 km a since 2001 (error estimated proba- Printer-friendly Version bilistically), with total losses of glacierised area of 11.1 % from 1988–2001 and 3.3 % from 2001–2009. Interactive Discussion

3568 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Tidewater glaciers on Western Trinity Peninsula remained stable between 1988 and 2009, and to date show only slow rates of retreat. They receive abundant snow from TCD prevailing south-westerly winds, and, unless strong perturbation to this system occurs, 5, 3541–3594, 2011 will probably remain stable in areal extent. This inference does not take account of 5 glacier thinning, which is observed in other parts of the Antarctic Peninsula, even after frontal stabilisation has occurred (Rott et al., 2011). In contrast, large tidewater glaciers Glacier inventory and on the Eastern Trinity Peninsula are apparently more vulnerable to continued climate glacier change warming, but they may stabilise in the future as they retreat towards their grounding 1988–2009 zones. B. J. Davies et al. 10 Glaciers on Trinity Peninsula that fed PGIS have stabilised since 2001, with slower annual recession rates since then. On James Ross Island, the largest areal changes have been from low-lying tidewater glaciers. Annual tidewater glaciers recession rates Title Page are likely to continue in response to continued atmospheric warming. The primary control for the widespread glacier retreat in Northeast Antarctic Peninsula is apparently Abstract Introduction 15 the observed climatic warming, with glacier size, length, slope, type, ELA and altitude exerting a strong mitigating or enhancing role. Conclusions References

Despite fears of continued run-away retreat and terminal destabilisation of tidewa- Tables Figures ter glaciers, this study shows that ice-shelf tributary glaciers are more likely to undergo a time-limited period of adjustment. Ultimately, ice-shelf tributary glaciers will ﬁnd a new J I 20 dynamic equilibrium, and then retreat slowly in response to warming climates and rising ELAs. We therefore anticipate that the results of this project will be relevant to studies J I concerned with the more southerly ice shelves that surround the Antarctic Peninsula. Back Close The behaviour of PGIS tributary glaciers and their long-term response to ice-shelf removal can be used to model and predict glacier response to contemporary and future Full Screen / Esc 25 ice-shelf disintegration events. Printer-friendly Version Supplementary material related to this article is available online at: http://www.the-cryosphere-discuss.net/5/3541/2011/tcd-5-3541-2011-supplement. Interactive Discussion zip

3569 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Supplementary Methods. Detailed information on methods used in glacier attribute data acquisition. TCD Supplementary Data. Dataset for the analysis of glacier change, with areas, lengths, 5, 3541–3594, 2011 and errors for 1988, 1997, 2001 and 2009. Also given are calculated rates of change 5 and the difference in rates of recession. Raw data and shapefiles are available from GLIMS (www.glims.org). Glacier inventory and glacier change Acknowledgements. This work was funded by NERC grant AFI 9-01 (NE/F012942/1). It is 1988–2009 a contribution to the SCAR ACE (Antarctic Climate Evolution) Programme. The authors are grateful for helpful and constructive criticism and comments from Hester Jiskoot and Tobias B. J. Davies et al. 10 Bolch. The authors acknowledge Etienne Berthier and the Centre National d’Etudes Spatiales (CNES) for the SPOT-5 images and the SPIRIT DEM. Neil Glasser was provided with no-cost access to ASTER images from NASA as a NASA-supported researcher. The 1997 glacier frontal positions were determined from the ADD (http://www.add.scar.org:8080/add/) Coastal Title Page Change shapefiles, mapped by Cook et al. (2005). Stefan Senk and Tristram Irvine-Fynne are Abstract Introduction 15 acknowledged for their help in programming and statistical analysis. Conclusions References

References Tables Figures

Abermann, J., Lambrecht, A., Fischer, A., and Kuhn, M.: Quantifying changes and trends in glacier area and volume in the Austrian Otztal¨ Alps (1969–1997–2006), The Cryosphere, 3, J I 205–215, doi:10.5194/tc-3-205-2009, 2009. 3543 J I 20 Aristarain, A. J., Pinglot, J. F., and Pourchet, M.: Accumulation and temperature measurements on the James Ross Island ice cap, Antarctic Peninsula, Antarctica, J. Glaciol., 33, 357–362, Back Close 1987. 3564, 3566 Benn, D. I., Hulton, N. R. J., and Mottram, R. H.: “Calving laws”, “sliding laws” and the stability Full Screen / Esc of tidewater glaciers, Ann. Glaciol., 46, 123–130, 2007a. 3567 25 Benn, D. I., Warren, C. R., and Mottram, R. H.: Calving processes and the dynamics of calving Printer-friendly Version glaciers, Earth-Sci. Rev., 82, 143–179, 2007b. 3567 Berthier, E., Arnaud, Y., Kumar, R., Ahmad, S., Wagnon, P., and Chevallier, P.: Remote sensing Interactive Discussion estimates of glacier mass balances in the Himachal Pradesh (Western Himalaya, India), Remote Sens. Environ., 108, 327–338, 2007. 3548 3570 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Bolch, T., Menounos, B., and Wheate, R.: Landsat-based inventory of glaciers in Western Canada, 1985–2005, Remote Sens. Environ., 114, 127–137, 2010. 3549, 3579 TCD Braithwaite, R. J. and Raper, S. C. B.: Estimating equilibrium-line altitude (ELA) from glacier inventory data, Ann. Glaciol., 50, 127–132, 2009. 3551 5, 3541–3594, 2011 5 British Antarctic Survey: James Ross Island, BAS 100 Series (topographic maps), Sheet 2, 1 : 100000, British Antarctic Survey, Cambridge, 1995. 3548 British Antarctic Survey: Antarctic Sound and James Ross Island, Northern Antarctic Penin- Glacier inventory and sula, Series BAS (UKAHT) Sheets 3A and 3B, 1 : 250000, Cambridge, United Kingdom glacier change Antarctic Heritage Trust, 2010. 3548 1988–2009 10 Brunt, K. M., Fricker, H. A., Padman, L., Scambos, T. A., and O’Neel, S.: Mapping the grounding zone of the Ross Ice Shelf, Antarctica, using ICESat laser altimetry, Ann. Glaciol., 51, 71–79, B. J. Davies et al. 2010. 3550 Carrivick, J. L. and Brewer, T. R.: Improving local estimations and regional trends of glacier equilibrium line altitudes, Geogr. Ann. A, 86, 67–79, 2004. 3551 Title Page 15 Carrivick, J. L. and Chase, S. E.: Spatial and temporal variability in the net mass balance of glaciers in the Southern Alps, New Zealand, New Zeal. J. Geol. Geop., 54, 415–429, 2011. Abstract Introduction 3551 Carrivick, J. L., Davies, B. J., Glasser, N. F., and Nyvlt, D.: Late Holocene changes in character Conclusions References and behaviour of land-terminating glaciers on James Ross Island, Antarctica, J. Glaciol., Tables Figures 20 submitted, 2011. 3550 Cook, A. J. and Vaughan, D. G.: Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years, The Cryosphere, 4, 77–98, doi:10.5194/tc-4-77-2010, J I 2010. 3543, 3547, 3568 Cook, A. J., Fox, A. J., Vaughan, D. G., and Ferrigno, J. G.: Retreating glacier fronts on the J I 25 Antarctic Peninsula over the past half-century, Science, 308, 541–544, 2005. 3543, 3548, Back Close 3552, 3570 Cooper, A. P. R.: Historical observations of Prince Gustav Ice Shelf, Polar Rec., 33, 285–294, Full Screen / Esc 1997. 3547 Czech Geological Survey: James Ross Island – Northern Part, Topographic Map 1 : 25000, Printer-friendly Version 30 Czech Geological Survey, Praha, 2009. 3548 Dahl, S. O. and Nesje, A.: Paleoclimatic implications based on equilibrium-line altitude de- Interactive Discussion pressions of reconstructed Younger Dryas and Holocene cirque glaciers in inner Nordfjord, western Norway, Palaeogeogr. Palaeocl., 94, 87–97, 1992. 3550 3571 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion De Angelis, H. and Skvarca, P.: Glacier surge after ice shelf collapse, Science, 299, 1560– 1562, 2003. 3543 TCD Evans, J., Pudsey, C. J., O´ Cofaigh, C., Morris, P., and Domack, E.: Late Quaternary glacial history, flow dynamics and sedimentation along the eastern margin of the Antarctic Peninsula 5, 3541–3594, 2011 5 Ice Sheet, Quaternary Sci. Rev., 24, 741–774, 2005. Ferrigno, J. G., Cook, A. J., Foley, K. M., Williams, R. S., Swithinbank, C., Fox, A. J., Thom- son, J. W., and Sievers, J.: Coastal-Change and Glaciological Map of the Trinity Peninsula Glacier inventory and Area and South Shetland Islands, Antarctica: 1843–2001, USGS, 32 pp., Denver, 2006. glacier change 3546, 3547 1988–2009 10 Fricker, H. A., Coleman, R., Padman, L., Scambos, T. A., Bohlander, J., and Brunt, K. M.: Mapping the grounding zone of the Amery Ice Shelf, East Antarctica using InSAR, MODIS B. J. Davies et al. and ICESat, Antarct. Sci., 21, 515–532, 2009. 3550 Fukuda, M., Strelin, J. A., Shimokawa, K., Takahashi, N., Sone, T., and Trombott, D.: Permafrost occurrence of Seymour Island and James Ross Island, in: Recent Progress in Antarctic Earth Title Page 15 Science, edited by: Yoshida, Y., Kaminuma, K., and Shiraishi, K., Terra Science Publishers, Tokyo, 745–750, 1992. 3546 Abstract Introduction Furbish, D. J. and Andrews, J. T.: The use of hypsometry to indicate long-term stability and response of valley glaciers to changes in mass transfer, J. Glaciol., 30, 199–211, 1984. 3551 Conclusions References Gille, S. T.: Warming of the Southern Ocean since the 1950s, Science, 295, 1275–1277, 2002. Tables Figures 20 3567 Gille, S. T.: Decadal-scale temperature trends in the Southern Hemisphere Ocean, J. Climatol., 21, 4749–4765, 2008. 3546, 3567 J I Glasser, N. F. and Scambos, T. A.: A structural glaciological analysis of the 2002 Larsen B Ice Shelf collapse, J. Glaciol., 54, 3–16, 2008. 3568 J I 25 Glasser, N. F., Kulessa, B., Luckman, A., Jansen, D., King, E. C., Sammonds, P. R., Scam- Back Close bos, T. A., and Jezek, K. C.: Surface structure and stability of the Larsen C Ice Shelf, Antarc- tic Peninsula, J. Glaciol., 55, 400–410, 2009. Full Screen / Esc Glasser, N. F., Scambos, T. A., Bohlander, J. A., Truffer, M., Pettit, E. C., and Davies, B. J.: From ice-shelf tributary to tidewater glacier: continued rapid glacier recession, acceleration Printer-friendly Version 30 and thinning of Rohss¨ Glacier following the 1995 collapse of the Prince Gustav Ice Shelf on the Antarctic Peninsula, J. Glaciol., 57, 397–406, 2011. 3544, 3547, 3562 Interactive Discussion Granshaw, F. D. and Fountain, A. G.: Glacier change (1958–1998) in the North Cascades National Park Complex, Washington, USA, J. Glaciol., 52, 251–256, 2006. 3548, 3579 3572 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Hambrey, M. J., Smellie, J. L., Nelson, A., and Johnson, J. S.: Late Cenozoic glacier-volcano interaction on James Ross Island and adjacent areas, Antarctic Peninsula, Geol. Soc. Am. TCD Bull., 120, 709–731, 2008. 3546 Heroy, D. C. and Anderson, J. B.: Ice-sheet extent of the Antarctic Peninsula region during the 5, 3541–3594, 2011 5 Last Glacial Maximum (LGM) – insights from glacial geomorphology, Geol. Soc. Am. Bull., 117, 1497–1512, 2005. 3546 Hock, R., de Woul, M., Radic, V., and Dyurgerov, M.: Mountain glaciers and ice caps around Glacier inventory and Antarctica make a large sea-level rise contribution, Geophys. Res. Lett., 36, 1–5, 2009. 3543 glacier change Holland, P. R., Jenkins, A., and Holland, D. M.: Ice and ocean processes in the Bellingshausen 1988–2009 10 Sea, Antarctica, J. Geophys. Res., 115, C05020, doi:10.1029/2008/JC005219, 2010. 3567 Hulbe, C. L., MacAyeal, D. R., Denton, G. H., Kleman, J., and Lowell, T. V.: Catastrophic ice B. J. Davies et al. shelf break up as the source of Heinrich Event icebergs, Paleoceanography 19, PA1004, doi:10.1029/2003pa000890, 2004. 3564 Hulbe, C. L., Scambos, T. A., Youngberg, T., and Lamb, A. K.: Patterns of glacier response to Title Page 15 disintegration of the Larsen B ice shelf, Antarctic Peninsula, Global Planet. Change, 63, 1–8, 2008. 3563, 3567 Abstract Introduction IPCC: IPCC Fourth Assessment Report: Climate Change 2007, Cambridge University Press, Cambridge, 2007. 3565 Conclusions References Jiskoot, H., Murray, T., and Boyle, P.: Controls on the distribution of surge-type glaciers in Tables Figures 20 Svalbard, J. Glaciol., 46, 412–422, 2000. Jiskoot, H., Curran, C. J., Tessler, D. L., and Shenton, L. R.: Changes in Clemenceau Icefield and Chaba Group glaciers, Canada, related to hypsometry, tributary detachment, length- J I slope and area-aspect relations, Ann. Glaciol., 50, 133–143, 2009. 3551, 3554, 3556, 3565, 3584 J I 25 King, J. C.: Recent climate variability in the vicinity of the Antarctic Peninsula, Int. J. Climatol., Back Close 14, 357–369, 1994. 3543 King, J. C., Turner, J., Marshall, G. J., Connelly, W. M., and Lachlan-Cope, T. A.: Antarctic Full Screen / Esc Peninsula climate variability and its causes as revealed by analysis of instrumental records, in: Antarctic Peninsula Climate Variability: Historical and Palaeoenvironmental Perspec- Printer-friendly Version 30 tives, edited by: Domack, E. W., Leventer, A., Burnett, A., Bindschadler, R., Convey, P., and Kirby, M.: Antarctic Research Series, American Geophysical Union, Washington, D.C., Interactive Discussion 17–30, 2003. 3545 Korona, J., Berthier, E., Bernard, M., Remy, F., and Thouvenot, E.: SPIRIT, SPOT 5 stereo- 3573 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion scopic survey of Polar Ice: reference images and topographies during the fourth International Polar Year (2007–2009), Int. Soc. Photogramme., 64, 204–212, 2009. 3548 TCD Lambrecht, A., Sandhager, H., Vaughan, D. G., and Mayer, C.: New ice thickness maps of Filchner-Ronne Ice Shelf, Antarctica, with specific focus on grounding lines and marine ice, 5, 3541–3594, 2011 5 Antarct. Sci., 19, 521–532, 2007. 3550 Laska, K., Prosek, P., and Budik, L.: Seasonal variation of air temperature at the Mendel Sta- tion, James Ross Island, in the period of 2006–2009, Geophysical Research Abstracts 12, Glacier inventory and EGU2010-3880, 2010. 3562 glacier change Leclercq, P.W., Oerlemans, J., and Cogley, J. G.: Estimating the glacier contribution to sea-level 1988–2009 10 rise for the period 1800–2005, Surv. Geophys., 32, 1–17, doi:10.1007/s10712-011-9121-7, 2011. 3543 B. J. Davies et al. van Lipzig, N. P. M., King, J. C., Lachlan-Cope, T., and van den Broeke, M.: Precipitation, sublimation and snow drift in the Antarctic Peninsula region from a regional atmospheric model, J. Geophys. Res., 109, D24106, 1–16, 2004. 3546, 3564, 3565 Title Page 15 Lopez, P., Chevallier, P., Favier, V., Pouyaud, B., Ordenes, F., and Oerlemans, J.: A regional view of fluctuations in glacier length in southern South America, Global Planet. Change, 71, Abstract Introduction 85–108, 2010. Martin, P. J. and Peel, D. A.: The spatial distribution of 10 m temperatures in the Antarctic Conclusions References Peninsula, J. Glaciol., 20, 311–317, 1978. 3545 Tables Figures 20 Mayewski, P. A., Meredith, M. P., Summerhayes, C. P., Turner, J., Worby, A., Barrett, P. J., Casassa, G., Bertler, N. A. N., Bracegirdle, T., Naveira Garabato, A. C., Bromwich, D., Campell, H., Hamilton, G. S., Lyons, W. B., Maasch, K. A., Aoki, S., Xiao, C., and van Om- J I men, T.: State of the Antarctic and Southern Ocean climate system, Rev. Geophys., 47, 1–38, 2009. 3546 J I 25 Meier, M. F. and Post, A.: Fast tidewater glaciers, J. Geophys. Res., 92, 9051–9058, 1987. Back Close 3563, 3567 Meredith, M. P. and King, J. C.: Rapid climate change in the ocean west of the Antarc- Full Screen / Esc tic Peninsula during the second half of the 20th Century, Geophys. Res. Lett., 32, doi:10.1029/2005GL024042, 2005. 3567 Printer-friendly Version 30 Morris, E. M. and Vaughan, A. P. M.: Spatial and temporal variation of surface temperature on the Antarctic Peninsula and the limit of viability of ice shelves, in: Antarctic Peninsula Climate Interactive Discussion Variability: Historical and Palaeoenvironmental Perspectives, edited by: Domack, E. W., Lev- enter, A., Burnett, A., Bindschadler, R., Convey, P., and Kirby, M.: Antarctic Research Series, 3574 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion American Geophysical Union, Washington, D.C., Vol. 79, 61–68, 2003. 3543 Oerlemans, J.: Extracting a climate signal from 169 glacier records, Science, 308, 675–677, TCD 2005. 3550, 3558, 3564 Osmaston, H.: Estimates of glacier equilibrium line altitudes by the Area x Altitude, the Area x 5, 3541–3594, 2011 5 Altitude Balance Ratio and the Area x Altitude Balance Index methods and their validation, Quaternary International 138–139, 22–31, 2005. Paul, F. and Svoboda, F.: A new glacier inventory on Southern Baffin Island, Canada, from Glacier inventory and ASTER data: II. Data analysis, glacier change and applications, Ann. Glaciol., 50, 22–31, glacier change 2009. 1988–2009 10 Paul, F., Kaäb,¨ A., Maisch, M., Kellenberger, T., and Haeberli, W.: Rapid disintegration of Alpine glaciers observed with satellite data, Geophys. Res. Lett., 31, L21402, B. J. Davies et al. doi:10.1029/2004GL020816, 2004. 3558 Paul, F., Barry, R. G., Cogley, J. G., Frey, H., Haeberli, W., Ohmura, A., Ommanney, C. S. L., Raup, B., Rivera, A., and Zemp, M.: Guidelines for the compliation of glacier inventory data Title Page 15 from digital sources, GLIMS, Global Land Ice Measurement from Space, NSIDC, University of Colorado, Boulder, 23 pp., 2010. 3549, 3550 Abstract Introduction Powell, R. D.: Grounding-line systems as second-order controls on fluctuations of tidewater termini of temperate glaciers, in: Glacial Marine Sedimentation; Palaeoclimatic Significance, Conclusions References Geological Society of America Special Paper 261, edited by: Anderson, J. B. and Ash- Tables Figures 20 ley, G. M., Boulder, Colorado, 75–94, 1991. 3567 Pritchard, H. D. and Vaughan, D. G.: Widespread acceleration of tidewater glaciers on the Antarctic Peninsula, J. Geophys. Res.-Earth, 112, F03S29, 1–10, 2007. 3543, 3563 J I Rabassa, J., Skvarca, P., Bertani, L., and Mazzoni, E.: Glacier inventory of James Ross and Vega Islands, Antarctic Peninsula, Ann. Glaciol., 3, 260–264, 1982. 3543, 3544, 3546, 3548, J I 25 3552, 3562 Back Close Racoviteanu, A. E., Paul, F., Raup, B., Khalsa, S. J. S., and Armstrong, R.: Challenges and rec- ommendations in mapping of glacier parameters from space: results of the 2008 Global Land Full Screen / Esc Ice Measurements from Space (GLIMS) workshop, Boulder, Colorado, USA, Ann. Glaciol., 50, 53–69, 2009. 3543, 3544, 3547, 3549 Printer-friendly Version 30 Raper, S. C. B. and Braithwaite, R. J.: Glacier volume response time and its links to climate and topography based on a conceptual model of glacier hypsometry, The Cryosphere, 3, Interactive Discussion 183–194, doi:10.5194/tc-3-183-2009, 2009. 3558 Rau, F., Mauz, F., de Angelis, H., Ricardo, J., Neto, J. A., Skvarca, P., Vogt, S., Saurer, H., and 3575 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Gossmann, H.: Variations of glacier frontal positions on the Northern Antarctic Peninsula, Ann. Glaciol., 39, 525–530, 2004. 3543, 3544, 3547, 3559, 3562, 3564 TCD Rau, F., Mauz, F., Vogt, S., Khalsa, S. J. S., and Raup, B.: Illustrated GLIMS Glacier Classifi- cation Manual, Version 1.0. GLIMS Regional Centre, “Antarctic Peninsula”, GLIMS (Global 5, 3541–3594, 2011 5 Land Ice Measurement from Space), NSIDC, University of Colorado, Boulder, 36 pp., 2005. 3549, 3579 Raup, B. and Khalsa, S. J. S.: GLIMS Analysis Tutorial, GLIMS, Global Land Ice Measurements Glacier inventory and from Space, NSIDC, University of Colorado, Boulder, 15 pp., 2010. 3549 glacier change Raup, B., Kaäb,¨ A., Kargel, J. S., Bishop, M. P., Hamilton, G., Lee, E., Paul, F., Rau, F., 1988–2009 10 Soltesz, D., Khalsa, S. J. S., Beedle, M., and, Helm, C.: Remote sensing and GIS technology in the Global Land Ice Measurements from Space (GLIMS) Project, Comput. Geosci., 33, B. J. Davies et al. 104–125, 2007a. 3549 Raup, B., Racoviteanu, A., Khalsa, S. J. S., Helm, C., Armstrong, R., and Arnaud, Y.: The GLIMS geospatial glacier database: A new tool for studying glacier change, Global Planet. Title Page 15 Change, 56, 101–110, 2007b. 3549 Reinartz, P., Muller,¨ R., Lehner, M., and Schroeder, M.: Accuracy analysis for DEM and or- Abstract Introduction thoimages derived from SPOT HRS stereo data using direct georeferencing, Int. Soc. Pho- togramme., 60, 160–169, 2006. 3548, 3550 Conclusions References Rignot, E., Casassa, G., Gogineni, P., Krabill, W., Rivera, A., and Thomas, R.: Accelerated ice Tables Figures 20 discharge from the Antarctic Peninsula following the collapse of Larsen B ice shelf, Geophys. Res. Lett., 31, doi:10.1029/2004gl020697, 2004. 3563 Rott, H., Skvarca, P., and Nagler, T.: Rapid collapse of Northern Larsen Ice Shelf, Antarctica, J I Science, 271, 788–792, 1996. 3544 Rott, H., Muller,¨ F., Nagler, T., and Floricioiu, D.: The imbalance of glaciers after disintegration J I 25 of Larsen-B ice shelf, Antarctic Peninsula, The Cryosphere, 5, 125–134, doi:10.5194/tc-5- Back Close 125-2011, 2011. Scambos, T., Hulbe, C., and Fahnestock, M.: Climate-induced ice shelf disintegration in the Full Screen / Esc Antarctic Peninsula, in: Antarctic Peninsula Climate Variability, edited by: Domack, E. W., Leventer, A., Burnett, A., Bindschadler, R., Convey, P., and Kirby, M.: Antarctic Research Printer-friendly Version 30 Series 79, American Geophysical Union, Washington D.C., 79–92, 2003. 3567 Scambos, T. A., Bohlander, J. A., Shuman, C. A., and Skvarca, P.: Glacier acceleration and Interactive Discussion thinning after ice shelf collapse in the Larsen B embayment, Antarctica, Geophys. Res. Lett., 31, L18402, doi:10.1029/2004GL020670, 2004. 3543, 3550 3576 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion Schiefer, E., Menounos, B., and Wheate, R.: An inventory and morphometric analysis of British Columbia glaciers, Canada, J. Glaciol., 54, 551–560, 2008. TCD Skvarca, P. and De Angelis, H.: Impact assessment of regional climatic warming on glaciers and ice shelves of the Northeastern Antarctic Peninsula, in: Antarctic Peninsula Climate Vari- 5, 3541–3594, 2011 5 ability: Historical and Palaeoenvironmental Perspectives, edited by: Domack, E. W., Leven- ter, A., Burnett, A., Bindschadler, R., Convey, P., and Kirby, M.: Antarctic Research Series, Vol. 79, American Geophysical Union, Washington, D.C., 69–78, 2003. 3547, 3558, 3559 Glacier inventory and Skvarca, P., Rott, H., and Nagler, T.: Satellite imagery, a base line for glacier variation study on glacier change James Ross Island, Antarctica, Ann. Glaciol., 21, 291–296, 1995. 3543, 3544, 3546, 3547, 1988–2009 10 3562 Skvarca, P., De Angelis, H., and Ermolin, E.: Mass balance of “Glaciar Bahia del Diablo”, Vega B. J. Davies et al. Island, Antarctic Peninsula, Ann. Glaciol., 39, 209–213, 2004. 3551, 3554, 3555 Smith, R. and Anderson, J. B.: Ice-sheet evolution in James Ross Basin, Weddell Sea margin of the Antarctic Peninsula: the seismic stratigraphic record, Geol. Soc. Am. Bull., 122, 830– Title Page 15 842, 2010. 3543 Smellie, J. L., Johnson, J. S., McIntosh, W. C., Esser, R., Gudmundsson, M. T., Hambrey, M. J., Abstract Introduction and van Wyk de Vries, B.: Six million years of glacial history recorded in volcanic lithofacies of the James Ross Island Volcanic Group, Antarctic Peninsula, Palaeogeogr. Palaeocl., 260, Conclusions References 122–148, 2008. 3546 Tables Figures 20 Sone, T., Fukui, K., Strelin, J. A., Torielli, C. A., and Mori, J. Glacier lake outburst flood on James Ross Island, Antarctic Peninsula region, Pol. Polar Res., 28, 3–12, 2007. 3562 Stastna, V.: Spatio-temporal changes in surface air temperature in the region of the Northern J I Antarctic Peninsula and South Shetland Islands during 1950–2003, Polar Science, 4, 18–33, 2010. 3545 J I 25 Svoboda, F. and Paul, F.: A new glacier inventory on southern Baffin Island, Canada, from Back Close ASTER data: I. Applied methods, challenges and solutions, Ann. Glaciol., 50, 11–21, 2009. 3549 Full Screen / Esc Turner, J., Colwell, S. R., Marshall, G. J., Lachlan-Cope, T. A., Carelton, A. M., Jones, P. D., 1015 Lagun, V., Reid, P. A., and Iagovkina, S.: Antarctic climate change during the last 50 years, Int. J. Climatol., 25, 279–294, 2005. 3543, 3546 Printer-friendly Version Vaughan, D. G. and Doake, C. S. M.: Recent atmospheric warming and retreat of ice shelves Interactive Discussion on the Antarctic Peninsula, Nature, 379, 328–331, 1996. 3543 Vaughan, D. G., Marshall, G. J., Connelly, W. M., Parkinson, C., Mulvaney, R., Hodgson, D. A., 3577 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion 1020 King, J. C., Pudsey, C. J., and Turner, J.: Recent rapid regional climate warming on the Antarctic Peninsula, Climatic Change, 60, 243–274, 2003. 3543, 3545, 3547, 3564, 3565 TCD van den Broeke, M. R. and van Lipzig, N. P. M.: Changes in Antarctic temperature, wind and precipitation in response to the Antarctic Oscillation, Ann. Glaciol., 39, 119–126, 2004. 3545, 5, 3541–3594, 2011 3546 1025 van der Veen, C. J.: Calving glaciers, Prog. Phys. Geog., 26, 96–122, 2002. 3567 Glacier inventory and glacier change 1988–2009

B. J. Davies et al.

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Abstract Introduction

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Table 1. Data sources used in Trinity Peninsula glacier inventory. TCD Notes Resolution Date Cap- Data Source 5, 3541–3594, 2011 tured ASTER VNIR 15 m Various Sensor on the NASA Terra (Advanced Spaceborne dates from Satellite. Level 1B Multispectral Glacier inventory and Thermal Emission and 2001 to images. Validated radiometric glacier change ∗ Reﬂection Radiometer) 2009 and geometric coeﬃcients ap- 1988–2009 plied. Coverage for each scene is 60 × 60 km. Datum: WGS84 Zone 21S B. J. Davies et al. LANDSAT-4 TM 75 m 29 Feb 1988 Panchromatic image. Scene ID: LT4215105160XXX11 9 Feb 1990 Panchromatic image. Scene ID: Title Page LT42161051990040XXX01 Abstract Introduction SPOT-5 (Satellite Pour 5 m with an Antarctic Captured at an incidence an- l’Observation de la absolute horizontal Peninsula: gle of −22.8◦, sun azimuth of Terre) HRS (High precision of 30 m 7 Jan 2006 55.2◦and sun elevation of 40.5◦. Conclusions References Resolution Sensor) RMS (Korona Panchromatic image. 120 km orthoimages et al., 2009) swath Tables Figures James Ross Captured at an incidence angle Island: of −22◦, sun azimuth of 55◦and J I 23 Jan 2006 sun elevation of 37◦. Panchro- matic image. 120 km swath J I SPIRIT DEM (SPOT-5 40 m. Absolute Dates as Derived from the above two Stereoscopic Survey of horizontal above for large footprint (120 km swath) Back Close Polar Ice: Reference precision of 30 m the two SPOT-5 HRS stereoscopic pairs Images and Topogra- RMS. Vertical pre- DEMs (Korona et al., 2009) Full Screen / Esc phies) cision ±6 m

Printer-friendly Version ∗ Refer to Supplement for further details of ASTER images. Interactive Discussion

Table 2. Sources of error and error mitigation in defining the area of each glacier polygon. TCD 5, 3541–3594, 2011 Sources of errors Uncertainty Mitigation Ice-divide and drainage basin ±10 % Multiple methods used for ice- Glacier inventory and identification divide identification (DEM, visual, glaciological interpreta- glacier change tions, slope, aspect, automatic 1988–2009 hydrology tools) B. J. Davies et al. Identification of glacier bound- 3 pixels Visual checks and buffer width of aries (digital mapping error) on (±22.5 m) 22.5 m on either side of glacier ASTER images polygon Title Page Identification of glacier bound- 3 pixels Visual checks and buffer width of aries (digital mapping error) on (±112.5) 112.5 m on either side of glacier Abstract Introduction LANDSAT image polygon Conclusions References Delineation of debris-covered ±0.5 % Visual checks and buffer width tongues (Bolch et al., 2010) (as above); checking over sev- Tables Figures eral images where possible

Scene quality, clouds, seasonal ±4 % Snow coverage of glacier mar- J I snow, shadows (Bolch et al., gins is covered in the Remarks 2010) column of the database. See J I also Table 2. Use of multiple im- Back Close ages aids the omission of seasonal snow Full Screen / Esc Error in co-registration and ±15 m Error is less than 3 pixels so is glacier size (Granshaw and (RMS) for included in the buﬀer above Printer-friendly Version Fountain, 2006) VNIR (Rau et al., 2005). Interactive Discussion

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Table 3. Methods of ELA calculation. Refer to the Supplement for more information. Altitudes Glacier inventory and are derived from the 2006 SPIRIT DEM, and these ELAs are therefore approximations for the glacier change year 2006. 1988–2009

Method Description Notes B. J. Davies et al.

ELAMEDIAN Median Elevation Represents an accumulation area ratio (AAR) of 50 %. Equivalent to HMEDIAN Title Page

ELAAAR Accumulation Area Ratio Assumes an AAR of 60 %; derived Abstract Introduction from hypsometric curves for the 2 54 tidewater glaciers over 40 km Conclusions References

ELATHAR Toe to Headwall Ratio Ratio between minimum and maxi- Tables Figures mum glacier altitude ELA Hess method Transition between convex and con- HESS J I cave contours J I ELATSL Transient Snow Lines Altitude of the snow line at the end of the ablation season Back Close

ELAMEAN Mean ELA Mean of ELAMEDIAN, ELAAAR, Full Screen / Esc ELATHAR

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B. J. Davies et al. Table 4. Summary table of the glaciers of the Northern Antarctic Peninsula. Error is determined by applying a 22.5 m buﬀer to either side of the glacier polygon. TP = Trinity Peninsula. JRI = James Ross Island. VI = Vega Island. IIC = Island Ice Caps. Title Page

Number of Total glacierised Total land % Glacierised Abstract Introduction Glaciers area (km2) area (km2) Conclusions References TP 62 5827 ± 154 6160 95 JRI 104 1781 ± 86 2378 75 Tables Figures VI 24 168 ± 15 253 66 IIC 4 365 ± 7 407 90 Total 194 8140 ± 262 9198 89 J I

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Table 5. Regression table for variables in the inventory. “n” is the number of observations. “ltg” Glacier inventory and means “land-terminating glaciers”. P -values are calculated at the 95 % conﬁdence level. glacier change 1988–2009 Variable A Variable B n Adjusted r2 Standard P value B. J. Davies et al. error

Mean Elevation (HMEAN) MeanECR 192 0.82 102.00 < 0.001 Maximum Elevation Glacier length 174 0.79 3.10 < 0.001 Title Page Maximum Elevation Glacier area 192 0.48 51.22 < 0.001 < . Mean Elevation Glacier area 192 0.30 59.57 0 001 Abstract Introduction Mean Slope Glacier area 192 0.05 69.38 0.001 Mean Slope Glacier length 174 0.08 3.14 < 0.001 Conclusions References Mean Aspect Mean Elevation 192 0.02 235.84 0.160 Mean Aspect Maximum Elevation 192 0.00 106.81 0.814 Tables Figures ELAMEDIAN ELAAAR 55 0.95 72.21 < 0.001 ELAMEDIAN ELATHAR 192 0.62 159.30 < 0.001 J I ELAMEDIAN ELAHESS 68 0.00 295.50 0.384 ELAMEDIAN ELATSL 152 0.00 263.88 0.290 1988 glacier area (ltg) Total area lost (ltg) 55 0.19 3.24 < 0.001 J I Width of calving tongue Total area lost 115 0.03 8.377 0.041 Back Close ELAMEAN Total area lost 186 0.04 200.10 0.003 Maximum Elevation Total area lost 186 0.14 428.78 < 0.001 Full Screen / Esc

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Glacier inventory and glacier change 1988–2009 Table 6. Summary of glacier descriptors. TP = Trinity Peninsula. JRI = James Ross Island. VI = Vega Island. IIC = Island Ice Caps. All = all glaciers. B. J. Davies et al.

TP JRI VI IIC All Title Page Tongue Grounded 31 24 10 4 69 Floating 10 16 2 0 28 Abstract Introduction Partially Floating 20 16 5 0 41 Land terminating 1 48 7 0 56 Conclusions References Primary Classiﬁcation Ice Cap 11 18 13 4 46 Tables Figures Ice Field 1 0 0 0 1 Outlet glacier 27 45 11 0 83 Valley Glacier 21 16 0 0 37 J I Mountain Glacier 1 17 0 0 18 Glacieret and snowﬁeld 1 8 0 0 9 J I Back Close

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B. J. Davies et al. Table 7. Number of glaciers in each hypsometric class. Categories are from Jiskoot et al. (2009). TP = Trinity Peninsula. JRI = James Ross Island. VI = Vega Island. IIC = Island Ice Caps. All = all glaciers. Title Page

Glacier Hypsometry TP JRI VI IIC All Abstract Introduction Class Description Value Conclusions References 1 Very bottom heavy > 1.5 35 42 1 1 79 2 Bottom heavy 1.2 < HI < 1.49 7 6 2 0 15 Tables Figures 3 Equidimensional −1.19 < HI < 1.19 11 11 4 1 27 4 Top heavy −1.2 < HI < −1.49 1 15 3 0 19 5 Very top heavy HI < −1.5 6 30 14 2 52 J I

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Table 8. Number of glaciers advancing and retreating in the period 1988 to 2009. Note that TCD missing data means not all 194 glaciers were included. Glacier change is only noted if it is greater than the mapped error (margin only buﬀer). “Stationary” glaciers have shown no 5, 3541–3594, 2011 change greater than the error.

Number of Glaciers Glacier inventory and 1988–2001 2001–2009 glacier change No. % No. % 1988–2009

All glaciers Retreating 160 89.9 146 79.3 B. J. Davies et al. Advancing 8 4.5 3 1.6 Stationary 9 5.6 35 19.0 Total 178 100 184 100 Title Page Trinity Peninsula Retreating 51 91.1 52 86.7 Advancing 4 7.1 0 0 Abstract Introduction Stationary 1 1.8 8 13.3 Total 56 100 60 100 Conclusions References

James Ross Island Retreating 91 91.0 76 73.8 Tables Figures Advancing 3 3.0 3 2.9 Stationary 6 6.0 24 23.3 Total 100 100 103 100 J I Vega Island Retreating 14 82.4 15 88.2 J I Advancing 1 5.9 0 0.0 Back Close Stationary 2 11.8 2 11.8 Total 17 100 17 100 Full Screen / Esc Island Ice Caps Retreating 4 100.0 3 75.0 Advancing 0 0 0 0 Printer-friendly Version Stationary 0 0 1 25.0 Interactive Discussion

Table 9. Glacier change, 1988 to 2009. Note there is particularly limited data for 1997. Error TCD margin for 2009 includes errors inherent in polygon determination. As analysis of frontal change in 2001 and 1988 assumes no migration of ice divides, error is calculated by using a 3-pixel wide 5, 3541–3594, 2011 buﬀer on either side of the ice front only, and is therefore a minimum error of ice front change only. Where data is missing, it is assumed that the glacier did not change in size between that year and the last year for which data was available; therefore, these ﬁgures are a minimum Glacier inventory and estimate. TP = Trinity Peninsula. JRI = James Ross Island. VI = Vega Island. IIC = Island Ice glacier change Caps. All = all glaciers. All area is given in km2. 1988–2009

Area Area 2009 Area 2001 Area 1997 Area 1988 B. J. Davies et al. All 8140.4 ± 261.7 8414 ± 49.1 8532.1 9460 ± 395.6 TP 5827.3 ± 153.9 5961.6 ± 28.4 5980.3 6689 ± 218.1 JRI 1780.5 ± 86.2 1902.4 ± 15.2 1992.6 2192 ± 136.1 Title Page VI 167.8 ± 14.8 169.8 ± 1.2 169.8 178 ± 19.3 IIC 364.7 ± 6.8 380.6 ± 4.8 389.5 400 ± 22.2 Abstract Introduction Area Lost 2001–2009 1988–2001 1997–2001 1988–2009 Conclusions References All 274.1 1045.5 117.7 1319.5 Tables Figures TP 134.3 727.8 18.7 862.0 JRI 121.9 290.0 90.2 411.9 VI 1.9 8.1 0.00 10.0 J I IIIC 16.0 19.6 0.00 35.6 J I Area Gain 2001–2009 1988–2001 1988–2009 All 0.09 0.08 0.13 Back Close TP 0.00 0.03 0.03 Full Screen / Esc JRI 0.06 0.05 0.10 VI 0.00 0.00 0.00 IIC 0.00 0.00 0.00 Printer-friendly Version

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59°0'0"W 58°0'0"W 57°0'0"W Snowfield Trin ity Peninsula and James Ross Isla nd Glacial Map

Research Stations Longitudinal Foliation GAP45 Esperanza WEDDELL GAP34 TCD Altitu de Pressure Ridges GAP48 SEA 200 m contours Rifts 930 m GAP43 Rivers Crevas sse (1988) GAP47 GAP46 GAP35 GAP36GAP42 Lakes GAP33 5, 3541–3594, 2011 GAP50 Moraine GAP GAP37 GAP49 41 GAP38 GAP32 2 GAP31 DUSE BAY

GAP5 720 m

LARSEN GAP53 GAP54 Andersson GAP51 Eyrie Bay GAP39 GAP40 ICE SHELF GAP30 Island Louis-Philipe Broad Valley Plateau Glacier inventory and GAP26 Cape GAP25 Russell West GAP23 GAP24 EAGLE ISLAND Green Glacier TRINITY PENINSULA glacier change GAP Glacier Extents 1988-2009 22 GAP55 Russell East Glacier extent and ice divides, 2009 GAP57 1280 m Glacier Long Island CORRY ISLAND Glacier extent 2001 Victory 1988–2009 Glacier Glacier extent 1997 Cape Lachman VEGA ISLAND GAP21 HER Pettus Mendel GIV10 Glacier extent 1988 GAP20 Glacier GIV12 GIV09 GAP58 Brandy BERT SOUND Ice outside study area GIV05 GAP56 Bay GIV29 GIV15 GAP59 Whisky GIV26 B. J. Davies et al. Bay GIV22 GAP19 GIV28 GAP18 Aitkenhead GIJR23 Glacier NEL St Martha The Naze GAP17 Diplock Cove EREBUS AND AN GIJR27 Glacier 660 m Terrapin 610 m TERROR GULF Hill Holluschickie GIJR72 Humps Island GAP15 Fjordo GAP60 Bay GA Ulu Peninsula Belen P1 GIJR GA 6 DOBSON P1 67 64°0'0"S 4 DOME 970 m Skep Point

64°0'0"S Title Page GAP1 down le GIJR84 GIJR134 GAP61 CROFT BAY GI GIJR137 GUSTAV CHCliffs GIJR132 3 GIJR92 GIJR93 JR Ula Point 64 Tumb 615 m GIJR61 Rum GIJR136 Cove GIJR90 GIJR131

GIJR87 Cape Gage Abstract Introduction GIJR95 PRINCE JAMES ROSS ISLAND Sjögren GIJR128 Glacier Boydell RÖHSS Cockburn Island Polaris GAP1 GIJR96 Glacier Glacier BAY HADDINGTON GIJR124 2 ICE CAP Persson GIJR97 1600 m Eliason GI Glacier Island JR123 Marambio Sjögren Inlet GIJR115 Conclusions References Pyke GAP11 Albone Glacier Rabot Point SEYMOUR Glacier GAP10 GAP07 ISLAND GIJR99 MARKHAM GIJR108 Swift BAY Cape Broms Tait GIJR122 Glacier GAP06 GAP08 Glacier GAP09 Hamilton Tables Figures Point GAP05 GAP03 GIJR109 UND LARSEN Nygren Point GIJR118 Y SO Jefford GIJR119 LT INLET GIJR106 Point GIJ GIJR117 MIRA Carlsson GIJR112 AD R113 SNOW HILL ISLAND 4 Bay P0 LOCKYER GA Cape SNOW_HILL GAP01 Foster ISLAND Projection: WGS UTM 1984 Zone 21S J I GAP02 Kilometres 05 102030 60°0'0"W 59°0'0"W 58°0'0"W 57°0'0"W J I

Fig. 1. Index map of James Ross Island, Vega Island, Snow Hill Island and Trinity Penin- Back Close sula, Northern Antarctic Peninsula, showing ice divides, glacier drainage basins and glacier ID codes. Glacier extents in 2009, 2001, 1997 and 1988 are shown. Remotely-sensed im- Full Screen / Esc ages (refer to Supplement) used in making this map and all subsequent maps were projected in the Universal Transverse Mercator (UTM) projection World Geodetic System (WGS) 1984 Printer-friendly Version Zone 21S. Interactive Discussion

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Glacier flowline 2009 GIJR72 GIJR54 GIJR55 GIJR76 GIJR56 GIJR71 GIJR67 TCD 200 m contours GIJR77 GIJR93 River Lake GIJR86 GIJR58 GIJR66 GIJR137 5, 3541–3594, 2011 GIJR92 GIJR84 Cirque headwall

Crevasse GIJR62 Moraine

GIJR90 GIJR94 Ice-free land Glacier inventory and GIJR136 glacier change GIJR64 GIJR61 1988–2009 GIJR95 GIJR128 64°10’0"S 64°10’0"S B. J. Davies et al.

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GIJR115 GIJR138 Abstract Introduction GIJR99

GIJR130 GIJR100 GIJR118A Conclusions References GIJR123A GIJR118 GIJR107 GIJR117 GIJR119 GIJR108 GIJR122 64°20’0"S Tables Figures 64°20’0"S GIJR104 GIJR120

GIJR109 GIJR116 GIJR121 GIJR110 GIJR105 GIJR106 GIJR114 GIJR103 J I

GIJR113 GIJR112 J I Kilometres GIJR111 06123 LOCKYER SNOW_HILL Back Close

58°0’0"W Full Screen / Esc Fig. 2. Subset of the glaciological map for James Ross Island, showing mapped Length in 2009 along the centre line of each glacier drainage basin. In the accumulation area, Length follows Printer-friendly Version the steepest downhill gradient; in the accumulation area, it follows the centre line as closely as possible. Length was measured from the highest to the lowest point on the glacier polygon. Interactive Discussion

TCD A B C 60 60 6000 2500 Count of glaciers All glaciers Area covered Trinity Peninsula 50 50 5000 5, 3541–3594, 2011 James Ross Island 2000 ) r2 = 0.79

Vega Island 2 Islands 40 40 4000 1500

30 30 3000 1000 20 20 2000

Area covered (km covered Area Glacier inventory and 500 Number of glaciers (n) Number of glaciers (n) 10 10 1000

0 0 0 0 (m a.s.l.) Glacier maximum elevation 2 2 2 2 2 2 2 glacier change 0510 15 20 25 30

> 1100 0.-99.99 Glacier length (km) 100-199.99200-299.99300-399.99400-499.99500-599.99600-699.99700-799.99800-899.99900-999.99 > 100 km 1000-1099.99 0.1-0.49 km 0.5-0.99 km 1.0-4.99 km 5.0-9.99 km 10.0-49.99 km 50.0-99.99 km Classes of mean altitude (m a.s.l.) Size class (km2) 1988–2009 D E F 2500 1600 25

1400 2000 20 1200 B. J. Davies et al. 1500 1000 r2 = 0.53 15

1000 800 10 600 500 400 5 0 200 Glacier mean slope (degrees)

Glacier mean elevation (m a.s.l.) Glacier mean elevation Title Page -500 0 0 Glacier maximum elevation (m a.s.l.) Glacier maximum elevation 0.01 0.1 1.00 10.00 100.00 1000.00 0.01 0.1 1.00 10.00 100.00 1000.00 0.01 0.1 1.00 10.00 100.00 1000.00 Glacier area (km2) Glacier area (km2) Glacier area (km2)

G H I Abstract Introduction 450 1800 1600 Trinity Peninsula 400 1600 1400 James Ross Island r2 = 0.95 Vega Island 350 1400 1200

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2 300 1200 100 250 1000 r2 = 0.62 800 200 MEDIAN 800 600 150 ELA 600 ELATHAR Tables Figures ELAAAR 400 100 400 ELATSL Glacier area (kmGlacier area (m a.s.l.) Mean elevation ELAHESS 200 50 200 ELAAAR ELATHAR 0 0 0 0510 15 20 25 30 0 200400 600 800 1000 1200 1400 1600 1800 0 50 100 150 200 250 300 350 Glacier length (km) Elevation (m a.s.l.) Mean aspect (degrees) J I

Fig. 3. (A) Number of glaciers with different mean elevations, separated according to region. J I (B) Frequency distribution of different glacier area classes, compared with total area covered by each size class. (C) Scatter plot showing a strong relationship (r2 = 0.8) between glacier Back Close maximum elevation and glacier length. (D) Relationship between maximum elevation and area (r2 = 0.5). (E) Scatter plot showing a weak relationship between mean elevation and glacier Full Screen / Esc area. (F) Scatter plot showing a weak relationship between mean slope and log glacier area. (G) Scatter plot showing a strong relationship between glacier area and glacier length. (H) Cor- Printer-friendly Version relation between ELAMEDIAN and different methods of ELA calculation. (I) Relationship between mean aspect and mean elevation. See Table 5 for p values. Interactive Discussion

Glacier Inventory 2009 AA Equilibrium Line Altitude B Tongue ELAMEAN 600 - 699.99 No Data 700 - 799.99 Floating 62 - 99.99 100 - 199.99 800 - 899.99 Partially floating 200 - 299.99 900 - 999.999 TCD Grounded 300 - 399.99 1000 - 1099.99 400 - 499.99 1100 - 1199.99 Land terminating 500 - 599.99 1200 - 1299.99 No data 5, 3541–3594, 2011

Glacier inventory and glacier change 1988–2009 Kilometres 0255012.5

Glacier mean aspect C Glacier Hypsometric class No data D B. J. Davies et al. NtoNE No data 1 - very bottom heavy NE to E ground 2 - bottom heavy EtoSE 3 - equidimensional SE to S 4-topheavy StoSW SW to W 5-verytopheavy WtoNW NW to N Title Page

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EFGGlacier mean aspect James Ross Island N Glacier Hypsometry Glacier Long Proﬁles Trinity Peninsula 45 2000 GIJR115 Trinity Peninsula Accumulation area Ice Fall Floating tongue GIJR123 Vega Island James Ross Island 1800 40 40 GIJR128 Vega Island Other Islands NW NE 35 1600

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S Full Screen / Esc Fig. 4. (A) Distribution of floating, partially floating and grounded glacier tongues at glacier termini. (B) Mean ELA for each glacier polygon. Glaciers in red have the highest ELAMEAN, Printer-friendly Version while glaciers in dark blue have ELAMEAN close to 100 m. (C) Mean aspect of the glacier polygons. (D) Distribution of glacier hypsometric classes. (E) Percentages of glaciers in each Interactive Discussion cardinal direction. (F) Frequency distribution of glaciers with different hypsometric indices in different regions. (G) Long profiles of three tidewater glaciers on James Ross Island. 3591 icsinPpr|Dsuso ae icsinPpr|Dsuso ae | Paper Discussion | Paper Discussion | Paper Discussion | Paper Discussion

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GAP12 GAP45 GAP07 HI = 2.1 HI = 1.8 HI = 1.5 GAP18 1 HI = 1.8 ELA =661 ELA =466 ELA =742 MEAN MEAN MEAN ELA =535 0.9 ELA = 1006 ELA = 811 ELA =1087 MEAN 2C 2C 2C ELA =880 2C 5, 3541–3594, 2011 0.8 0.7 0.6 ELA ELA ELA2C 0.5 2C 2C ELA2C 0.4 0.3 0.2 ELAMEAN ELA ELA ELA MEAN MEAN MEAN Glacier inventory and 0.1 0 glacier change Top heavy Equi-dimensional GAP13 GAP60 GAP53 HI = -1.5 HI = -3.4 GAP14 HI = 1.2 1 HI = -1.1 1988–2009 ELA =1194 ELA =559 ELAMEAN =893 MEAN ELA =876 MEAN 0.9 ELA = 1539 MEAN ELA = 904 ELA2C = 1238 2C ELA = 1221 2C 0.8 2C 0.7 ELA2C 0.6 ELA2C ELA ELA 0.5 2C 2C B. J. Davies et al.

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e James Ross Island s i l Bottom heavy Equi-dimensional Title Page a GIJR108 HI = 2.0 GIJR72 GIJR128 GIJR136 1 HI = 3.0 HI = 1.8 HI = 1.1 m ELA = 312

r MEAN ELA =221 ELA = 721 ELA = 741 0.9 MEAN MEAN MEAN ELA2C =657 ELA = 1066 o ELA2C = 566 2C ELA2C = 1086 0.8 N 0.7 Abstract Introduction ELA 0.6 2C ELA2C 0.5 ELA2C ELA2C 0.4 0.3 Conclusions References 0.2 ELA ELA ELA 0.1 MEAN MEAN MEAN ELAMEAN 0 Tables Figures Top heavy

GIJR115 GIJR97 GIJR123 GIJR27 HI = -1.5 HI = 1.6 1 HI = -1.7 HI = 1.0 ELA =791 ELA2C ELA = 158 ELAMEAN =1067 MEAN ELAMEAN =812 MEAN 0.9 ELA = 1136 ELA =362 ELA ELA2C =1412 2C ELA2C = 1238 2C 0.8 2C 0.7 J I ELA2C 0.6 ELA2C 0.5 0.4 0.3 J I 0.2 ELA ELAMEAN ELAMEAN MEAN 0.1 ELAMEAN 0 00.20.40.60.81 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 0 0.2 0.4 0.6 0.8 1 Back Close Normalised cumulative area

Full Screen / Esc Fig. 5. Normalised hypsometric curves of representative tidewater glaciers on Trinity Peninsula and James Ross Island. Hypsometric Index (HI) and mean equilibrium line altitude (ELAMEAN) Printer-friendly Version are given in the top right hand corner for each glacier graph. The normalised ELAMEAN for each glacier is plotted. ELA2C indicates the possible change in equilibrium line with future climate change. A 2 ◦C warming could result (presuming an adiabatic lapse rate of −5.8 ◦C/1000 m) in Interactive Discussion a rise in ELA of 345 m by 2040.

TCD

A B C 16 1.0 1 1 0 GIV10 0 GIJR01 5, 3541–3594, 2011 V V I I

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r 5 c G I a G a -40% a a l e l l 0% G i h G g % g c c a l g % -60% Title Page 3 252 89 0 252 89 0 250200 150 100 50 0 Months to February 2009 Months to February 2009 Months to February 2009 G H

16 - 3 0 5 A 2 0 5 1 0 5 4 6 8 7 0 9 6 25 4 3 22 38 7A 8A 4 08 1 5 6 4 01 48 5 7 91 8 7 47 1 139 21 R R37 R8 R R7 R R51 R53 R R45 R R0 R49 R5 R R J JR42 JR52 J JR24 JR J JR J JR05 JR JR JR J J J J JR34 JR38 J J J JR70 J J Abstract Introduction R13 R R1 R R1 ) 12 1 I I I I I I I I IJR03 I IJR I I IJR I I IJ I J J JR130 J J J JR110 JR120 I I I I R R 1 GI GIJR39 GI G GI GIJ G G GI G GI G GI GI G G GI G G G GIJR76 GI G GIJR04 G G GI G GIJ G G GI G G J J - IJR120A I I G GIJR1 GI GIJR1 G G G GI GI 14 GI G GIJR11 G G a 0% < 1 km2 2 m k

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a -0.2% G e J 2 t Tables Figures a n GIJR 1988-2001 R o GIJR 2001-2009 0 -3.5 -3-2.5 -2 -1.5 -1 -0.4 0 Area lost (km2), 1988-2009 Land-terminating glaciers J I Fig. 6. (A) Percentage change in surface area for land-terminating glaciers on Vega Island. Many glaciers receded after 1997 and 2001. (B) Recession over time of land-terminating J I glaciers on Vega Island. (C) Percentage change for small land-terminating glaciers (less than 1 km2) on James Ross Island. (D) Glacier change for small land-terminating glaciers on James Back Close 2 Ross Island. (E) Percentage change for land-terminating glaciers > 3 km on James Ross Full Screen / Esc Island. (F) Glacier change for and-terminating glaciers (greater than 3 km2) on James Ross Island. (G) Scatter plot demonstrating a weak correlation between change in glacier area and Printer-friendly Version initial glacier size (r2 = 0.11; see Table 5). (H) Variance in rates of change for land-terminating glaciers on James Ross Island. Interactive Discussion

TCD 5, 3541–3594, 2011

A B 0 2001-2009

1988-2001 ) 1 WesternTrinityPeninsula - Glacier inventory and

a -0.2 2 m k (

e glacier change -0.4 g n a

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n Non-tributary glaciers

A PGIS tributary glaciers -1.2 -0.50 0.00 0.50 1.00 1.50 2.00 2.50 3.00 010152053025 Rate of change in glacier length (km a-1) Glacier Length 2009 (km) Title Page C D 16 1.6 8 s

Abstract Introduction r GAP12

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Fig. 7. Tidewater glacier length. (A) Rates of glacier length change in tidewater glaciers on Back Close Trinity Peninsula. (B) Scatter plot showing poor correlation between 2009 glacier length and length changes. (C) Chart illustrating change in glacier area for tributary glaciers to Prince Full Screen / Esc Gustav Ice Shelf. Note that most change occurred prior to 2001. (D) Scatter plot showing poor correlation between the width of the calving front and the change in glacier length. Printer-friendly Version

Interactive Discussion

Glacier change Glacier change 1988-2001 AB2 -1 2 -1 Recession 1988-2009 km a Recession 1988-2001 km a GAP34 GAP45 -9.195000 - -6.560000 -12.929000 - -9.963000 -9.962999 - -3.701000 GAP32 -4.345000 - -2.353000 TCD -3.700999 - -2.061000

GAP53 GAP31 GAP40 -1.818000 - -1.312000 -2.060999 - -1.097000

GAP51 -0.956000 - -0.627000 -1.096999 - -0.646000

GAP39 GAP23 -0.573000 - -0.402000 -0.645999 - -0.401000 -0.218000 - -0.115000 -0.400999 - -0.223000 GAP55 5, 3541–3594, 2011 -0.222999 - -0.131000 GAP58 -0.108000 - -0.067000 -0.130999 - -0.089000 -0.065000 - -0.037000 -0.088999 - -0.054000 GAP56 -0.036000 - -0.014000 -0.053999 - -0.028000 -0.012000 - 0.002000 -0.027999 - -0.009000 Insufficient data -0.008999 - 0.000000 GAP61 0.000001 - 0.053000 GAP60 GAP14 GAP15 Insufficient data GIJR64 GIJR61 GAP07 Glacier inventory and GIJR136 Former glacier extents

Glacier extent 2001 GIJR115 glacier change Glacier extent 1988 GAP08 GAP05 Kilometres 0255012.5 1988–2009 GAP02 SNOW_HILL B. J. Davies et al. Glacier change 2001-2009 Difference in glacier recession Recession 2001-2009 CD2 -1 Difference in recession km a Faster 1988-2001 -2.671000 - -2.355000 Faster 2001-2009 -2.354999 - -1.447000 No recession -1.446999 - -0.811000 Same rate of recession -0.810999 - -0.396000 Insuficient data -0.395999 - -0.212000 -0.211999 - -0.114000 Title Page -0.113999 - -0.070000 -0.069999 - -0.042000 GAP18 -0.041999 - -0.023000 GAP17 -0.022999 - -0.007000 -0.006999 - 0.000000 Abstract Introduction 0.000001 - 0.136000 Insufficient data Conclusions References

Tables Figures

Fig. 8. Annualised rates of recession for diﬀerent time periods. Glaciers in red retreated fastest, J I and glaciers in dark blue had the slowest annual recession rates. Glaciers in pink advanced. J I Recession category values are determined by Natural Breaks (Jenks) method. (A) Overall glacier recession, 1988–2009. Note the slow rates of recession on Western Trinity Peninsula. Back Close (B) Glacier rates of recession, 1988–2001. PGIS tributary glaciers retreated fastest. Note that two PGIS-tributary glaciers in Rohss¨ Bay advanced during this period (coloured purple). (C) Full Screen / Esc Glacier rates of recession, 2001–2009. Note a few small advancing glaciers (coloured purple). (D) Diﬀerence in recession rates. Glaciers in blue retreated fastest between 1988 and 2001; Printer-friendly Version glaciers in red retreated fastest after 2001. Note that PGIS tributary glaciers retreated slower after 2001. Interactive Discussion

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