Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 2 and ć 38.4 km ± , Poland ń ), being one of the most negative from 1 − 6154 6153 in 2009/11) has been primarily caused by accelerating 0.05 mw.e.a 2 ± ecki ([email protected]) ł 0.63 4.6 km 12.1 % glacier area decrease in DL (i.e. from 334.1 − ± ( ± 1 − 0.06 ma ± ecki ł 0.70 This discussion paper is/has beenPlease under refer review to for the the corresponding journal final The paper Cryosphere in (TC). TC if available. Cryosphere Research Department, Adam Mickiewicz University, Pozna Svalbard regional means known from thefor literature. If other the same similar figure wascontribution regions to to be total of applied Svalbard central mass balancearea. Spitsbergen, despite Glacier negligible changes that proportion in to would Dickson total(ELA) Land glacier result shift, were which linked in to in a dramatic therequired equilibrium period considerable for line 1990–2009/11 steady-state. altitude has The been massbe located balance ca. therefore more 500 of m sensitive central higher to Spitsbergen than climate glaciers change seems than to previously thought. 1 Introduction Small glaciers are natural indicators ofby climate, change as they of record their even thickness, itswarming slight length caused oscillations and volume area loss (Oerlemans, of ice 2005).to masses 20th recent on century a rates climate global of scaleglaciers (IPCC sea-level 2013), rise and contributing (SLR) ice in caps,the about their largest a fresh-water half. ice-masses input Despite in to relatively the SLR small world: area is Antarctic of of and similar Greenland magnitude ice as from sheets (Radi during LIA to 207.4 termini retreat. The− mean 1990–2009/11 geodetic mass balance of glaciers was Hock, 2011; Gardner et al.,changes 2013). of Therefore all it glaciers is on both of hemispheres. great importance to study volume Abstract Svalbard is aincluding heavily Dickson glacier Land covered (DL),Ice are archipelago Age occupied in by (LIA) the smalla changes Arctic. alpine comprehensive glaciers, Its remain analysis which centralfrom of only post-Little topographic regions, glacier sporadically maps and changes investigated. digital2009/11. in elevation This The models DL (DEMs) study 37.9 based for presents LIA, on 1960’s, 1990 inventories and compiled The Cryosphere Discuss., 9, 6153–6185,www.the-cryosphere-discuss.net/9/6153/2015/ 2015 doi:10.5194/tcd-9-6153-2015 © Author(s) 2015. CC Attribution 3.0 License. Strong ELA increase causes fastloss mass of glaciers in centralJ. Spitsbergen Ma Published by Copernicus Publications on behalf of the European Geosciences Union. Received: 25 September 2015 – Accepted: 9Correspondence October to: 2015 J. – Ma Published: 6 November 2015 5 15 20 10 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | – 0 ska, 27 ◦ ń and have a total C, being relatively 2 ◦ km 3 10 with length of ca. 80 km × 2 km 3 10 × for the period 1981–2011 (Førland et al., 1 − 6155 6156 C decade ◦ E. Its area is 1.48 0 7 ◦ (Nuth et al., 2013; Martín-Españyol et al., 2015). It is located C, with summer (June–August) mean of 4.9 –17 3 ◦ 0 16 km ◦ 5.1 3 − 10 × N and 15 0 ecki, 2013a, 2015a). No meteorological stations are operating in DL-N, but the ł 10 ◦ Climate of DL shows strong inner-fjord, quasi-continental characteristics, i.e. reduced Coastal zones of Svalbard receive the highest precipitation and experience low One of the regions situated the furthest from maritime influences (ca. 100 km) Previous glacial research performed in DL-C focused mainly around impact of glacier The archipelago of Svalbard is one of the most significant arctic repositories of in close proximityconsidered to as very warm sensitive to West changing2003). climatic Climate Spitsbergen and record oceanic Current suggests conditions a and (HagenSvalbard sharp, et terminating early its al., the 20th Little century cryosphere Ice air AgeCooler is temperature period period increase (LIA) hence between in around 1940’s 1920’s and (Hagentemperature et 1960’s trend, al., was being 2003). followed ca. by 0.5 a strongly positive summer 2011; Nordli et al., 2014). Climateparticularly warming after has led 1990 to volumeet (Hagen loss al., of et 2007, Svalbard 2010, al., glaciers, 2013; 2003; Moholdt Kohler et al., et 2010; al.,summer James et 2007; al., temperature, Sobota, 2012). 2007;Spitsbergen, hence Nuth the are largestdistance heavily from island the glacier-covered. open of seastemperature limits In the moisture during transport summer contrast, archipelago, with months simultaneouset (Hagen shows interior increase al., in et 2014). little air al., Response of of 1993; glaciers icemuch Nuth to climate et more area change al., in seldom, because 2013; theseoverall districts probably Przybylak Svalbard has because glacier been studied mass of balance. their presupposed lowis significance Dickson in Land the changes (DL). of This their geometry paper sincearea the inventorizes Little and all Ice length, Age ice as (LIA).The masses This well aim includes of as changes of of recent DL this their in volume and central study fluctuations Spitsbergen quantifies is using and to aerial tomass balance. estimate investigate photogrammetry. contribution recent of mass similar balance regions to of total an Svalbard inner-fjord region 2 Study area The study region is located in central Spitsbergen and stretches between 78 79 Lufthavn weather station (SVL,and 15 ma.s.l.) 2010 near Norwegiantemperature Longyearbyen of town. Meteorological Between Institute 1981 measured at SVL average annual precipitation andregions. increased The summer southernmost air inlet of temperature DL when is compared located about to 20 km coastal north from Svalbard in north–south directionglaciological analysis and DL typical(DL-C) was divided and width into north ofplateau-type three (DL-N) mountains, 20–30 subregions km. (Fig. with – Foricefields summits 1). south and reaching (DL-S), the DL-S ice-masses 500–600 central is ma.s.l., purpose plasteredthe the occupied along greatest of by lowest gentle ice-cover the small slopes.exceeding elevated and 1000 DL-C m. and the The is largest dominated mountains thepart, in glaciers, by subregion DL-N but mostly are with glaciers even oforiented slightly valley (mainly towards higher the than type, of north. in and the valley summits central and niche types) are smaller here and mostly volume of 7 high as for Svalbard. Annual measuredof precipitation sea-level was 188 air mm. temperature In DL-C are daily very means similar as at SVL (Rachlewicz and Styszy retreat on landscapeGibas remodelling et (e.g. al., Karczewski, 2005;2010, Rachlewicz 1989; 2012; et Kostrzewski al., Ewertowski et 2007; and al., Rachlewicz, Tomczyk, 2009a, 1989; 2015; b; Evans Ewertowski et et al., al., 2012; Szpikowski et al., 2007; Láska et al., 2012), but(Ma over glaciers it drops relatively fast withgeneral increasing climatic altitude pattern suggests(Hagen it et al., is 1993). among the driest zones in the whole Svalbard terrestrial ice. Glaciers cover 57 % of the islands with 34 5 5 15 10 10 15 20 25 25 20 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1 − ecki, ł ecki, 2014). ł ), mean aspect S cient to reach maximum ecki et al., 2013). Also, ł ffi ), mean slope ( L ), length ( 6157 6158 A uravlev et al., 1983; Troicki, 1988) and recently cial NPI inventories (Norwegian Polar Institute, Ž ffi cient to accurately reproduce subtle decadal changes of ffi ecki, 2013a, 2014; 2015b). Glaciers in central and eastern ł ecki et al., 2013; Ewertowski, 2014). Glaciers of DL-N and DL-S have not ł Glacier boundaries for 1960’s epoch were manually digitized as polygons in ArcGIS Glaciers of DL are mostly very small hence their dynamics are low. The maximum software from scannedof and glaciers georeferenced was paperoutlines, estimated maps but S100 by no information adding series. was2009/11 The area available outlines for LIA of their were lateral area their taken extent moraine from in that o zones time. to 1990 and 1960’s glacier 3.2 Calculation of glacier geometry parametersFrom and modern their glacier boundaries changes and 2009/11could DEM main be morphometric extracted. characteristics Those were area ( from Norwegian Polar Institute100 (NPI). 000 The S100 source series of topographicNPI 1960’s taken maps glacier between constructed 1960 geometry and from were 1966. 1the As 1 : analysis, a : 50 20 1990 000 m and digital aerial 2009/11 elevation topographicInstitute, imagery models background 2014a). (DEMs) for by They by were NPI constructed were from0.5 used m 1 (Norwegian resolution : Polar 15 aerial 000 imagery aerial (2009/11),and photographs projected fit (1990) into and into a a common commonand datum cell ETRS Kääb grid. 1989 (2011) Universal co-registration provedrecent procedure DEM proper origins described mainly XYZ by from Nuth 2011, alignment2009 but aerial eastern of part images. both of DL-C datasets. was covered Data with earlier for the most 2014b), which proved tocomparable be size accurate separated by during a direct medial morainefor field were Ebbabreen, surveys. treated the as Confluent individual largest glaciers units, glacierpossible, except of in minor DL, tributary historicallywere considered glaciers fixed as which as one individual eventually object. glaciersglacier Where separated also in result from the from earlier the ice epochs,Very main so small melt-out, area stream episodic rather changes snow of thanglacier a fields from bodies given and disconnection were elongated of excludedin narrow former from time patches tributaries. and the connected did inventory. with notJotunfonna Hydrological were account main ice-divides not for further were changing divided ice fixed into topography. Small glacier icefields basins. Frostisen and very small glaciersglacier in extents DL. from LIA, Therefore, 1960’s, glacier 1990 inventories and from 2009/11) this were created paper with (covering use of data A ready-to-use Svalbardet glacier al. geometry (2013) product wasDue by inspected to König as large, et aboundaries Svalbard-wide al. potential was scale (2013) data often source and of insu for Nuth König/Nuth the catalogue purpose the of precision this of study. glacier visual inspection of 2009/11 aerialHoegdalsbreen/Arbobreen imagery system, by Norwegian Manchesterbreen Polarcharacterised Institute and by revealed that Vasskilbreen deformed (looped) systemtheir past flow are surge lines behaviour. and/or moraines, which may indicate 3 Data and methods 3.1 Glacier geometry data also on Svenbreen (Ma 2013b; Ma (Rachlewicz, 2009a), while on smaller glaciersIn it is every several times subregion loweroutlet however (Ma surge-type of glaciers Frostisen(Hagen occur. icefield, et Studentbreen, al., north-eastern surged 1993),position around but from its 1930. front earlysurged Fyrisbreen advance 20th was surged probably by century around in far (compare insu 1960 late with 19th map or by early Lid, 20th 1928). century Hørbyebreen (Ma been studied yet. ice velocity measured on largest ice masses of the region did not exceed 12 ma 2014; Strzelecki et al., 2014;were Pleskot, performed 2015). on More Bertilbreen detailed glaciological (e.g. investigations part of DL-C lose their mass and retreat their fronts (Rachlewicz et al., 2007; Ma 5 5 10 20 25 15 25 15 20 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | , ), (2) (1) L mor min and H H t , d α ers, new V/ and , ff S , d t med d H , L/ , d max t d H could be converted to , was calculated for each A/ t ), length changes (d d min A L H H/ has been then calculated using er from errors associated with ff ) and mean elevation change for V V ” signs. Including these bu ). d + h d ” and “ 6160 6159 . − 3 − 6.4 % as a region-wide total and being larger for the by the average area of a glacier over the period 1990– er with “ ± ff ), all given also as annual rates (d V H , respectively for each of the analysed epochs). ) 2011 2011 A A , elevation change pixel grids have been first calculated for each ice 2 + of icefields with multiple outlets. Several parameters were used as V L were computed for each polygon for 2009/11. 1990 . In some cases more centrelines must have been used, e.g. to measure 2 1990 A A , 1990 ( med A H × for each glacier, with × 1960 0.5 km V A respectively). All rates of glacier change indicators were computed according to h 1 d , d and t < 1960 d was inferred by dividing d = = erences between new and original values have been used as an error estimate A ), minimum, maximum, median and moraines elevation ( Near-surface glacier density changes were not considered in this study as they were To compute d max ff max max H H H/ V A α areas of DLDi glaciers have beenof computed andsmaller compared ice to masses. all Since no original maps polygons. are available for LIA maximum, LIA glacier area general map accuracyconsiderable extent of or winter snow cover misinterpretations onbeen aerial used images. made To account as for by that, ahas 25 horizontal m cartographers, been has uncertainty assigned e.g. of a glacier 25 due m polygon bu digitalisation. to Each polygon Kohler et al. (2007)measured have shown cumulative a mass gooddensity match balance changes between may on geodetic be and a neglectedsmall glaciologically- in and small geodetic retreating balance NW ice calculations masses Spitsbergen on in comparatively Svalbard. glacier, Therefore, implying d assumed to be smallthe when study compared period tozones climatically-induced 1990–2009/11. of elevation This changes glaciers, over where assumptionvariations. changes is However, in more direct firnindicate uncertain field thickness that may in surveys lead in the and toexclusively late highest of analysis considerable summer glacier density ice of the or highest available superimposed ice glacier satellite and zones almost images no in firn DL is are present. Moreover, composed almost geodetic mass balance (givenby in an metres average of ice water density of equivalent, 900 m kgm w.e.)3.3 by multiplication Errors Glacier area measurements for 1960/66 epoch su d 2009/11 to account for glacier retreat. d d the year of validity of geometry data. the following equation: d mass by subtraction ofmass change 2009/11 measurement DEM over frominformation long of 1990 thickness time DEM. changes scalesthe It over (Cox the mass is and entire balance an March glacier valuesglaciological accurate with 2004), from no method providing method. single need of of reference Inboundaries extrapolation points (here the such 1990 as resulting area) stakeschange raster, have used value been in pixels for averaged direct each lying to 1990 obtain glacier within polygon representative the ( elevation larger glacier respectively) and theoreticalan steady-state accumulation equilibrium area line ratio( altitude of 0.6. (tELA), Area assuming was measured for each polygon and epoch the period 1990–2009/11 (d ( epoch along the centrelinesirregular of ice 62 masses largest with valley,that niche used no to and dominant share cirque front flowA glaciers, with direction, excluding the former main glacier minor in tributary their basin glaciers and very small glaciers with volume changes over the period 1990–2009/11 (d representative indicators of glacier fluctuations, including area changes (d H 5 5 25 20 10 15 15 20 25 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | t ), d 2 (3) ect, . For ff were H/ σ ◦ erence among ff could be t d typical for H t H/ d erence of over ), Hørbyebreen H/ ff 2 and d V is the sample size. N (14.0 % of the region). values, while standard erence uncertainty and ff 2 h . The largest glaciers are and 86 of them are smaller d and its standard deviation 2 2 t d 4.6 km ) in DL-S and DL-N respectively. 2 H/ 1 km ± < erence between the two DEMs was ff rather than number of sample points. 2 , clearly decreasing with increasing glacier erences between 1990 and 2009/11 DEMs ◦ ff er around LIA outlines resulted in total glacier 6162 6161 ff ers described above. ff ). North-facing glaciers (N, NW and NE) comprise 2 value, 2 standard deviations of mean d is used as point elevation di ) and 9.8 % (51.0 km t 50 m bu 2 d σ ± for individual glaciers. Elevation measurement error of H/ ) elevation di ε ε ( ) 11.5 % for that epoch. For 1990 and 2009/11 epochs lower h 2 m and less than 5 % are characterized by elevation di σ ± d 2 ± 5 m have been used, resulting in area uncertainty estimates of ), Cambridgebreen/Baliollbreen system (16.3 km 25 m), among which average d × 2 ± ± n ( becomes glacier size in km + 5 m (Fig. 2). Mean elevation di ] N has been then calculated using Eq. (3): ± N σ √ . Only 9 glaciers (6 %) are larger than 5 km ε 10 and 2.2 % for the whole DL region. Uncertainties of length measurement for 2 , was 2.68 m. Here × ) ± ± σ ) and Jotunfonna (14.0 km n is a fraction of the glacier extending above 550 m and 2 and errors or glacier area measurements, uncertainties of d − n ε [(1 ers of ff The 1990 DEM does not fully cover major glaciers in eastern DL-C (Ebbabreen, To estimate error of DL-C is the subregion with the heaviest glacier-cover with 25.9 % (117.1 km = 3.4 and excluded from the analysis.70 The % of results pixels is have within shownof that more elevation than di 0.24 m, a correction further subtracted from all obtained bu ± over non-glacier covered terrainsurfaces in in the DL whole study are region relatively were poorly measured. inclined, Since mountain ice slopes steeper than 20 each year were set according to the bu whereas it is only 7.7 % (39.3 km area. (15.9 km 61 % of the population,and while SE). only 16 The % mean of ice glacier masses slope have is a 10.7 southern aspect (S, SW Ragnarbreen, Bertrambreen and Pollockbreen), which representglacier 16.6 area % of of the DL, modern measured so directly. their To elevation estimate changes their for 1990–2009/11 1990–2009/11 period thinning could rates, not d be assessed with conventional errorfor propagation the methods. smallest ice All masses errors and are vice relatively versa. large their tELA has been used, since this parameter proved high correlation with d Ebbabreen (24.3 km Using (described further inwith the similar Results tELA section). ( This was done by selecting ice masses 110 ice masses (72 % ofthan the 0.5 population) km have area parts of glacier surfaces extendingon above 1990 550 and ma.s.l. 2009/11 (being aerial an imagery) approximate have snowline a prescribed error characteristic of 2 ε were computed and assigned toestimate the for glacier such with obtained no d direct measurements. As an error snow-covered surfaces was however expected to beareas larger than due for to rocks and its vegetated lower radiometric contrast on aerial images. To account for this e In the most recent 2009/11terminating inventory on 152 the ice masses land have and been catalogued covering in in DL, total all 207.4 deviation, is further used to compute each glacier the group of glaciers with similar tELA was used. 4 Results 4.1 Modern geometry of Dickson Land glaciers estimation is based onzones. Such 1960/66 approach outlines assumes only andlateral frontal geomorphological retreat retreat in mapping most the likely of periodcould took moraine LIA-1960’s, place but have some as been well.Application eroded Also, of a moraine until relatively deposits large the ofarea some aerial error glaciers estimate photogrammetry of era or not formed at all. where Assuming spatial autocorrelation of elevationet errors al. on the (2007) order of 1000 m after Nuth 5 5 25 20 20 10 15 15 10 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 1 A ± − a was (e.g. 2 t 1 0.14 d − − . Details 3 A/ 0.85 km ± er from minor ff 200 ma.s.l.) mean 2.01 su < − observed in DL were do not however give t L d t d L/ A/ in DL was highly negative at t d H/ after 1990 (Fig. 4a). Exclusion of known 1 − ), resulting in total mass balance of a 1 2 − 6164 6163 , e.g. due to bedrock sills dissecting thinning t (Fig. 7d), indicating it was its main control. It has d L L/ 0.48 km ± , while at the average tELA (ca. 500 ma.s.l.) it was about 1 0.05 mw.e.a was elevation of the bulk of glacier ice, here represented − 2.23 ± t er significantly in their area-altitude distribution. DL-N has − , average length change rates d d ff t d 2 ma H/ 0.63 − in the first epoch, which decreased fourfold to − A/ 1 was correlated with terminus altitude and glacier length, so low- ( − 1 12.1 % (Fig. 4a; Table 1). The overall rate of area change d a L − 2 ± . Subregional values are given in Table 2 and indicate the most negative 3325 m. Epochs LIA–1960’s or 1960’s–1990 were the periods of the fastest . Positive fluctuations were observed just above 1000 ma.s.l. on average 1 1 − − − 0.06 ma 0.66 km ± ± In contrast to d 0.6 ma 0.70 46 and 0.49 of DL-C, having thethinning largest rates. portion d ofelevated low-elevated fronts ice, of had long thewas glaciers best highest have correlated glacier-wide been with retreatingalso relative at d shown the good fastest correlation rates.and with length, Relative so glacier d large area glaciers (Fig. lost the 7e), smallest maximum fraction elevation of (Fig. their maximum 7f) extent despite by median elevation and tELAthe (Fig. highest 7a, Table elevated 3). glaciers In of result, in DL-N the have epoch been 1990–2009/11 thinning the slowest, while glaciers specific mass balance in DL-C and the least negative4.4 in DL-N. Statistical analysis of glacier changeThe controls main driver for d change rate was ca. (Fig. 6a). Some glaciers have been thinning at very high rate exceeding 1 ma 0.01 Gta glacier snouts into active andThe dead vast ice majority zones of (e.g. glaciers (77.4study Ebbabreen, %) period Frostisen, has Svenbreen). 1990–2009/11. been retreating at their fastest rate in4.3 the last Glacier thinning and mass balance A strikingly negativehighest elevation zones change of glaciers pattern allchange is over were DL evident found (Fig. only from 5). onor Considerable the mountain-top high zones ice data, elevated of patch glaciers positive on also Gavlhaugen). elevation in At in DL-N the (Kaalaasbreen, lowest the altitudes Arbobreen ( − − Manchesterbreen and Sophusbreen), while fewbalance small (Fig. ice 6b). patches Overall, have average been area-weighted closer d to − retreat for 22.6 % ofsupported the studied short-term glaciers. boost In many of of d these cases bedrock topography after 1960 and further to a clear picture of the ongoing trend. uncertainties. With the available temporalcontinuously resolution of retreating the and dataevents all no of glaciers single have Frostisen been and front1930 and Fyrisbreen advance 1960 respectively occurred was (Hagen et during detected, al., the 1993). Extreme although first total d surge analysed period, about The subregions also di and probable surge-typedynamic glaciers, instabilities, gives which athe may region good change and insight confirms their intorather that the than extent increasing climate-induced ice area due area loss dynamics to changes rates (Fig. are in internal 4b). related Large to error climate forcing bars of d 4.2 Glacier area and length reduction Since the termination of the LIAin glaciers total of DL by have 37.9 been continuously losing their area, most of highglacier elevated fronts glacier reach areamost the of flat lowest DL and elevations, and containsof while the median the glacier lowest two elevation fraction hypsometry latter ofDL of subregions of of 614 high m. 539 are DL-S m elevated 520 In and m, ishave areas. tELA DL-C giving low the of Median overall 504 elevated elevations ma.s.l. median termini.glacier Larger elevation glaciers The of elevations. tend further glaciers Total to in bevolume volume north, scaling longer, of the less parameters steep by higher DL Martín-Español and of are et ice glacier al. geometry maximum masses, (2015), characteristics and is are estimated roughly median depicted in 12 with km Fig. empirical 3. area- − 5 5 25 20 15 10 25 20 15 10 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | (1936– 1 − ecki (2013b) ecki, 2013a). ł ł ecki, unpublished after 1990. Kohler ł 0.15 ma 1 − − , being similar to values 1 − 0.78 ma in the period 1960’s–1990, − 1 − = t 1.21 ma d − H/ 0.49 ma for six small land-terminating glaciers all − , confirmed that geodetic equilibrium was 0.28 to 1 t − − d 6165 6166 H/ of two small land-terminating glaciers in Spitsbergen with ranged from t t d d H/ ecki 2013b). . Thinning of glaciers will also lead to decay of temperate ice ł H/ 1 (2003–2005) for Midre Lovénbreen in NW Spitsbergen. James − 1 − erent response times of glaciers or albedo feedbacks, which could ff 0.69 ma ecki, 2013b) to 1000 ma.s.l. after 1990. Despite the fact that it may not ł − ecki et al. (2013). The only exception in DL is a small glacier Arbobreen, former ł Wide-spread acceleration of area and length loss rates indicates that glaciers in DL Almost no thickening is apparent in the highest zones of glaciers in DL, since Another consequence of dramatic ELA increase is that local surge-type glaciers may followed by an acceleration of mass loss rate to d greater temporal resolutionacceleration than of available for their this thinning study over and the concluded 20th continuous century, e.g. from et al. (2007) analysed d of the LIA,documented in line mean with net earlier mass studies. For change seven of glaciers in DL-C Ma 1962) to et al. (2012)over documented Svalbard since negative 1960’s and d reportedof post-1990 them. increase Their of recent mass d loss rates for four have been experiencing an increasingly negative mass balance since the termination significant absolute arearegions and of length the losses. globeglacier In (e.g. aspect Li contrast shown and to no Li,what statistical reports 2014; correlation may Fischer from with result et any many al.,insolation from of other at 2015; glacier summertime slopes Paul change with and midnight-sun parameters, north Mölg over and 2014), south Svalbard aspects and when compared more to mid-latitudes. balanced 5 Discussion In agreement with2007, earlier 2010; studies 2013; Jamescontrol from of et Svalbard the al., observed (Kohler 2012),station negative et has climate glacier been al., mass warming clearly balance increasing iset 2007; in in anticipated al., DL. Nuth 1920’s as 2014), and Air et 1930’s, temperature the whatepoch as at al., respectively. main explains well SVL However, as glacier clear after retreatmay 1990 post-1960 not after (Nordli mass be LIA loss simply maximumtotal acceleration explained glacier and of by area in DL loss increased rate the air glaciers rates quadrupled last temperature. doubled, (though In despite with study large the thevery uncertainty) period fact similar and 1960–1990 that front as mean retreat inSvalbard multidecadal is the summer evident first at air that epoch temperature timeit and (Pohjola was seems et no likely al., that decrease 2001; Hagen average insmall, summer et al., winter low-activity air 2003). temperature glaciers snow In is in accumulation this notbe context DL over the for and only example driver other di of factorsmodify change glacier may of mass also balance play infrom a a accumulation non-linear role. zones pattern, Those and e.g. hence could byJames increasing removal of et energy high-albedo al., absorption firn 2012; (Kohler et Ma al., 2007; observed in DL. mean zero-elevation change1990 line (Ma has shiftednecessarily from agree with ca. the 600 true mon ELA retreating in (due stagnant to glaciers the ice ofelevation period DL submergence change the in 1960’s– line. latter accumulation Direct could zones), GPS bewith measurements expected maximum to on flow be Svenbreen similar velocity (DL-C), to small of zero- glacier only 3 ma nearly equal to the true ELA for the period July 2010–July 2012 (Ma tributary of Hoegdalsbreen, which seemsa to rate undergo up slow to high-elevationzones, thickening 0.25 which at ma are still found beneath the largest glaciers of DL (Ma Therefore, the presented resultsregion indicate has already that raised thewill above ELA eventually their lead of highest to points mosthas their (typically glaciers stopped. complete 700–800 ma.s.l.), in As melt-out, suggested even the what located by if study at glacier the ca. geometry atmospheric 500 analysis, m warming the in trend order average ELA for the should modern be not glaciers build to up be towards in newunder steady-state. surges present and climate as conditions, suchMa as could demonstrated be in removed more from detail the for surge-cycle Hørbyebreen by 5 5 25 10 15 20 15 10 20 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 0.48 vs. ± in total to calculated , excluding 1 2 1 − − for the period (Hagen et al., 1 1 − − a 2 38.4 km . It is a considerable 4.3 Gta 9.7 Gta 1 ± − − − 12.1 % decrease. Post- of glaciers in Hornsund, ± 2 0.5 Gta 0.36 mw.e.a − − mean specific mass balance of 1 − 0.12 to (based on dataset by Nuth et al., 2013). − 2 6168 6167 ) or Nuth et al. (2010) ( 1 0.05 mw.e.a − ± of small glaciers in DL (ca. 1 km 2 0.63 8.8 Gta − was to be applied also for NL and BL, that would result in − 1 − respectively. Front retreat of 62 test-glaciers has been accelerating ) land-terminating glaciers with total volume estimated to be roughly 1 2 − in 2009/11, corresponding to an overall 37.9 a 2 2 0.63 mw.e.a − 4.6 km . Local glaciers have been losing their extent at an accelerating rate since 0.66 km ± 3 ± The three regions of central Spitsbergen, i.e. DL, Nordenskiöld Land (NL) and In opposition to relative area changes, specific mass balance of glaciers in central The trend of acceleration of glaciers’ front retreat in DL over the 20th and 21st aszczyk et al. (2013) concluded increasing area loss rates for tidewater glaciers ł by Moholdt et al. (2010). Fasterby mass Wouters loss rates et from Svalbard al. were also (2008) reported, ( e.g. value when compared to Svalbard-wide surface mass balance of Austfonna and Kvitøya ice caps).inner-fjord Nevertheless, glaciers the presented in studybalance than Spitsbergen points most that interior regions small ofglacier may Svalbard. area Despite (ca. have their 2 negligible %), more contribution morefuture to concern negative glacier the should mass total specific be balance puttheir mass on of valleys their the under evolution archipelago, to conditions as better of estimate well fast deglaciation. as on changing functioning of 6 Conclusions In thisSpitsbergen, study has new beenmodels multi-temporal compiled released with inventory by use Norwegian ofsmall of (up Polar to snow/ice Institute. glaciers 24 km outlines At in present and the digital Dickson region elevation is Land,the covered Little central with Ice Age termination (early 20th century), from0.49 334.1 12 km 1990 area loss rate has been 4.5 times that in the epoch LIA-1960’s, i.e. 2.23 Bünsow Land (BL) (Fig.and 1) their are total similar in glacier terms cover of is climate, ca. topography 800 and km glaciology mass balance contribution from these three regions of often considered to beat the a most similar sensitive to rate climate as warming, ca. have 200 been km losing area Since the geodeticobtained balance for single measured glaciersjustified for in to DL NL assume is (e.g.balance it of Troicki, comparable is 1988; representative with Bælum for and mass central Benn, balances Spitsbergen. 2011), If it the is specific mass 207.4 et al., 2007). However, at Spitsbergen hasresistant been to previously climate change considered due by to much some drier researchers climate and as higher hypsometry relatively (Nuth 1990 and 1990–2009/11, ina clear contrast decrease to in studyB area by loss rates Nuth for etin entire al. Svalbard Hornsund, after (2013), south 1990. who On Spitsbergen. concluded the Interestingly, other ca. hand, 800 km LIA-2000’s). centuries is similar asZagórski on et most al., land-terminatingLIA glaciers 2008; of relative James Svalbard glacier et (Lankauf, areaconclusions al., 2007; by decrease 2012; Ziaja in (2001) Nuth and DLsmaller et Nuth was et glaciers, al., al. high loses (2013) 2013). with thatregions its The central of 37.9 ice Spitsbergen, %, associated Svalbard. with Area cover supporting post- much loss extent previous rates at in DL a have been relatively at higher similar rate level between than 1960’s– maritime data). Consequently, it will impact their hydrology,ice geomorphological activity and flow reduce dynamics,(Hodgkins as et al., documented 1999; Lovell for et al., other 2015). small glaciers in central Spitsbergen glaciers in DL is amongmass the most balance negative is from Svalbard, estimated which overall to recent range surface from 2003; Nuth et al.,from 2010; several Moholdt factors, et but al.,their primarily 2010). theoretical High from steady-state mass high ELA lossarea/basin position (tELA). rates of The area in other true DL ratios, factors ELA maystronger strongly could climate result when be forcing influencing compared than their in to energy low coastal glacier zones balance of of Svalbard. their valleys, and/or 5 5 10 15 20 25 15 20 10 25 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | in the last 1 − ). It was related to 1 0.1 ma − ± 0.05 mw.e.a ± 0.63 − in the period from the maximum to 1960’s, ( 1 1 − − 6170 6169 0.1 ma 0.06 ma ± ± from small glaciers in the interior of Spitsbergen, a figure 1 − The study is a contribution to DIL*ICE project (Dickson Land Ice Masses 0.5 Gta between 1960’s and 1990 and as much as 17.1 er, W. T., Kaser, G., Ligtenberg, S. R. M., Bolch, T., Sharp, M. J., Hagen, J. O., − ff 1 − 0.1 ma ± The most important finding of this study is fast glacier-wide thinning over the entire (Tellbreen, Svalbard), investigated by149, ground doi:10.5194/tc-5-139-2011, 2011. penetrating radar, The Cryosphere, 5,(Southern 139– Svalbard) since the2013. beginning of the 20th century, Pol. Polar Res.,techniques, 34, Gulkana 327–352, Glacier, Alaska, USA, J. Glaciol., 50, 363–370,system, 2004. Svalbard, Journal of Maps, 8, 146–156, 2012. Svalbard, Geogr. Ann. 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A., Wahr, E.: J., Berthier, E., with time, being on average 5.1 9.4 contribution of which should becontrast considered to most in regionslow-activity future of the glaciers, assessments archipelago, which of Dicksonrather Land adjust Svalbard than is to mass occupied by new byprovide balance. large very climate a In changes small, conditions better, inglaciers by easier the in more enhanced ice to maritime melting, zones flux interpret of and the climate archipelago. calving indicator front than retreat. larger,The Hence, mostly Supplement they related tidewater to this. doi:10.5194/tcd-9-6153-2015-supplement article is available online at Acknowledgements. Evolution, RiS id062940). 4894) The supported author deeply byInstitute. appreciates Comments the the of J.O. open-access Polish Hagen data National on policy the Science early of manuscript the Centre are Norwegian (grant also Polar greatly no. acknowledged. 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C., Isaksson, E., Vaikmae, R., and van de Przybylak, R., Ara Rachlewicz, G.: Contemporary Sediment Fluxes and Relief Changes in High Arctic Glacierized Rachlewicz, G.: River floods in glacier-covered catchments of the high Arctic: Billefjorden- 5 5 10 15 25 30 20 15 10 20 25 30 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | t d 0.1 0.1 0.1 0.1 ± ± ± ± H/ 9.8 8.4 6.1 8.4 0.04 0.05 0.10 0.07 0.28 0.05 ) − − − − 1 ± ± ± ± ± ± − (ma and d t 0.55 0.63 0.67 0.71 0.56 0.62 t 0.1 0.1 0.1 0.1 d d ± ± ± ± − − Mass balance − − − − L/ V/ 19.7 18.1 11.4 17.2 − − − − 0.05 0.06 0.11 0.06 0.32 0.06 0.2 0.2 ± ± ± ± ± ± ) (mw.e.) 0.3 0.1 ± ± t 1 ± ± − d 10.0 10.1 7.0 9.4 − − − − 0.61 0.70 0.74 0.79 0.63 0.69 H/ − − d − − − − 0.2 0.2 0.2 0.1 ± ± ± ± , and their rates d 1.1 1.2 2.2 1.2 6.6 1.2 H 6.6 4.7 3.6 5.1 ± ± ± ± ± ± − − − − and d 12.8 14.7 15.6 16.6 13.1 14.5 H − − d − − − − V 14.4 % 11.0 % 13.3 % 12.1 % ± ± ± ± ) (m) (ma Max–2009/11 Max–1960’s 1960’s–1990 1990–2009/11 Max–2009/11 1 44.4 33.1 41.7 37.9 A − − − − − a 3 6176 6175 13.0 1.8 2.22 4.56 2.3 12.5 3.3 12.0 ± 1.43 0.92 ± ± ± ± ± ± ± ± ± and tELA. t t d d 31.0 35.0 160.6 94.6 70.6 24.0 V/ H/ d − − − − − − 4.10 117.07 8.57 207.44 1.71 39.32 2.74 51.05 ± ± ) (millionsm ± ± 3 ) Area change, Length change rates, d 2 273 256 67 46 247 37 ± ± ± (km ± ± ± A 11.81 137.88 19.34 251.98 735 3372 1987 1482 505 651 Area, 4.17 50.27 3.35 63.83 V ± ± Volume and elevation changes, d ± ± − − (millionsm − − − − ∗ 18.14 159.55 38.42 302.18 8.25 63.98 12.03 78.65 ± ± ± ± Elevation changes, volume changes and mass balance of glaciers in subregions of Changing extent of glaciers in Dickson Land in the study periods. estimates based on the relationship between d DL-N Total Subregion d DL-C (total) DL-C Surveyed DL-C Unsurveyed DL-S ∗ DL-CDL-S 174.95 67.40 DL-N 91.76 Total 334.11 Subregion Max 1960’s 1990 2009/11 d Table 2. Dickson Land over the period 1990–2011. Table 1. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 0.59 0.43 0.02 max − 0.18 0.18 − − L ) 2011 0.03 0.09 A 0.33 0.33 0.28 0.25 − − 0.23 0.24 0.46 − − − ) ln( max A 0.48 0.43 0.35 ln( 0.26 − 0.37 0.57 − − 0.33 0.50 0.50 0.01 level. t 0.08 0.05 = d − − Longitude Latitude H/ p 0.37 1 0.19 0.11 0.08 d α 0.03 0.190.23 0.16 0.04 0.28 0.20 0.11 0.14 L − cos 0.02 0.00 − − 0.03 0.09 − 1 0.37 0.78 Relative d 0.62 0.50 0.27 0.31 − − − − S L 0.21 0.08 0.23 0.08 0.11 0.21 tELA 0.41 0.70 0.37 0.790.44 0.59 0.59 0.21 0.42 0.60 0.49 Relative d 0.19 1 0.08 0.10 mor 0.46 0.23 0.18 0.73 − 0.03 H t d L/ 0.37 0.691 0.54 0.35 d 6178 6177 0.14 0.22 max − 0.35 − 0.38 H 0.51 t d 0.20 0.24 0.26 0.07 0.06 0.16 0.12 min 0.15 0.16 L/ − − 0.43 0.53 H − − 0.69 0.19− 0.16 d cients for glacier change indicators against other indicators ffi med 0.22 0.11 0.72 0.69 0.31 0.67 0.74 0.41 0.19 H 0.13 0.15 1 A 0.08 0.11 − 0.40 1 d 0.25 0.20 0.32 2011 0.41 0.35 0.02 − − L 0.640.53 0.24 A 0.21 0.59 0.59 0.35 0.70 0.78 0.79 0.44 0.54 0.41 0.40 d Max–2009/11 1990–2009/11 Max–2009/11 1990–2009/11 Max–2009/11 1990–2009/11 Max–2009/11 1990–2009/11 L L Pearson correlation coe Continued. Max–2009/11 1990–2009/11 1990–2009/11 Max–2009/11 L L t t t d d d Max–2009/111990–2009/11 0.19 0.16 0.16 Max–2009/11 1990–2009/11 t t t d d d 1990–2009/11 Max–2009/11 1 H/ L/ L/ A A Relative d Relative d d d d d d H/ A L/ L/ A d Relative d d d d Relative d d Table 3. and geometry parameters. Bold values indicate statistical significance at Table 3. Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | map of (b) 6180 6179 Map of Svalbard with location of regions of central (a) erences between 2009/11 DEM and 1990 DEM over non ff Location of the study area. Histogram of elevation di Figure 2. glacier-covered terrain. Spitsbergen: Dickson Land (DL), Nordenskiöld Land (NL) and Bünsow Land (BL); Figure 1. Dickson Land and its subregions: north (DL-N), central (DL-C) and south (DL-S). Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | . (a) (h) , scatter plot of glacier (f) . Frequency distribution of (b) and mean aspects (e) 6182 6181 and relative area ice cover , slopes (d) (a) and average glacier length change rates in Dickson Land and (b) and scatter plot of latitude against maximum glacier elevations (g) , median elevations (c) Total Dickson Land glacier area changes and area change rates for all glaciers Glacier geometry in Dickson Land in 2009/11. Altitude of ice cover in subregions of Figure 4. and non-surging glaciers only its subregions: north (DL-N), central (DL-C) and south (DL-S). Figure 3. Dickson Land against absolute area glacier areas slopes against ln(area) Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | (a) (d) and southern average elevation (c) (a) , central (b) 6184 6183 : ©Norwegian Polar Institute. (a) An example of glacier area changes in northern Dickson Land in Delbreen region Glacier thinning in Dickson Land over the period 1990–2009/11: frequency distribution of geodetic balances. Figure 6. change curves for Dickson(b) Land (with one standard deviation bars) and its subregions and Figure 5. and mean 1990–2009/11 elevation change rates in northern Dickson Land with location of3 glaciers mentioned – in the Hoegdalsbreen, text:patch, 1 4 8 – – – Kaalaasbreen, Sophusbreen, 2 Fyrisbreen,Gonvillebreen, 9 – 13 Arbobreen, – 5 – Manchesterbreen, – Stensiobreen, 1017 14 – Vasskilbreen, – – Baliolbreen, 6 Ebbabreen, Hørbyebreen, 11 15 18 – – –Frostisen. – Cambridgebreen, Base Delbreen, Ragnarbreen, Svenbreen, 12 map 16 19 – 7 for – – – Bertrambreen, Bertilbreen, 20 Gavlhaugen – ice Pollockbreen, 21 – Jotunfonna, 22 – Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | 6185 Scatter plots of selected glacier change indicators against geometry parameters or Figure 7. other indicators.