View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Available online at www.sciencedirect.com ScienceDirect Polar Science 8 (2014) 86e95 http://ees.elsevier.com/polar/ Fifty years of meteo-glaciological change in Toll Glacier, Bennett Island, De Long Islands, Siberian Arctic Keiko Konya*, Tsutomu Kadota, Hironori Yabuki, Tetsuo Ohata Research Institute of Global Change, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 236-0061, Japan Received 4 April 2013; revised 30 September 2013; accepted 11 October 2013 Available online 1 November 2013 Abstract Rapid environmental change has been observed in the De Long Islands, Siberian Arctic, where warming has extensively occurred over the area. To quantitatively evaluate glaciological changes since the 1980s, the climate, mass balance, and the equilibrium line altitude (ELA) of Toll Glacier on Bennett Island were analyzed. Air temperature has increased and solid pre- cipitation has decreased since the 1960s, especially after 2000. The cumulative mass balance of Toll Glacier has had a negative trend since the 1960s and reached approximately À20 m water equivalent (w.e.) in 2000, which is one of the largest changes in the Arctic. These changes are much larger than those in the west Russian Arctic. The warming trend is also correlated with the sea ice distribution in the Siberian Arctic and may lead to feedback effects that cause further Arctic warming. Ó 2013 Elsevier B.V. and NIPR. All rights reserved. Keywords: Arctic glacier; Mass balance; Siberia 1. Introduction (IPCC), the total volume of Arctic glaciers is projected to decrease by between 13% and 36% by 2100, which The Arctic region has shown a noticeable warming corresponds to a sea-level equivalent (SLE) increase of trend over the last century, especially during the winter 51e136 mm, with estimates varying in different gen- and spring (Polyakov et al., 2003). Even in summer eral circulation models (AMAP, 2011). The largest and autumn, the area around 180E experienced severe mass-loss contributions to sea level rise have come warming in the early 2000s (Serrezze et al., 2009). As from the Arctic, with values of 0.09 mm yÀ1 SLE from a consequence of warming, the mass balance of many 1960/1961 to 1989/1990 and 0.19 mm yÀ1 SLE from Arctic glaciers is negative, and the glaciers are 1990/1991 to 2002/2003 (Lemke et al., 2007), and the shrinking (e.g., AMAP, 2011; De Woul and Hock, Russian Arctic is expected to experience the third 2005; Dowdeswell et al., 1997; Gardner et al., 2013; largest change of glacier volume in the Arctic in the WGMS, 2009). Since the glacier areas are small, the 21st century (Radic and Hock, 2011). contribution of Arctic glaciers to sea level rise is small Little or no observational research has been con- (Jacob et al., 2012). Under the A1B emissions scenario ducted in much of the Arctic and northeastern Eurasia, of the Intergovernmental Panel on Climate Change including the Eurasian continent side of the Arctic Archipelago. Basic inventory data are lacking for * Corresponding author. Tel.: þ81 468679271. Arctic glaciers (AMAP, 2011). Although many glaciers E-mail address: [email protected] (K. Konya). 1873-9652/$ - see front matter Ó 2013 Elsevier B.V. and NIPR. All rights reserved. http://dx.doi.org/10.1016/j.polar.2013.10.002 K. Konya et al. / Polar Science 8 (2014) 86e95 87 exist in the Russian Arctic, the fluctuations of most of 149.0E) is 30 km long and 10 km wide. Although only these glaciers are poorly known because observations three ice caps are shown in the map in Fig. 2, Verkulich either were abandoned some decades ago or not made et al. (1992) identified four glaciers on Bennett Island at all. However, some glaciers in western Russia, such through their field observations. Table 2 lists the distri- as at Franz Josef Land and Severnaya Zemlya, are well bution, area, altitude, thickness, and mass balance of the studied. These glaciers were observed until the 1980s, glaciers on Bennett Island. The smaller icecap on the west and their retreats have been reported (Barkov et al., side of the island is composed of two glaciers, De Long 1992; Glazovsky and Macheret, 2006; Govorukha, East and De Long West. Maliy Glacier, on the east side of 1987; Grosswald et al., 1973; Kameda, 1995; the island, is the smallest ice cap, and Toll Glacier is the Zeeberg and Forman, 2001). largest. The altitudes of the top of the Toll, De Long West, Research is also limited in the De Long Islands, and Maliy glaciers are 384 m, 426 m, and 200 m, Siberian Arctic. Verkulich et al. (1992) provided the respectively (Kotlyakov, 1997). only detailed report on glaciers on Bennett Island, Snow depth ranged from about 50e85 cm on the three based on observations made in the 1980s. De Long smaller glaciers, which is about one-half that for Toll Islands is within the area that has experienced exten- Glacier. Snow thickness was uniform on the small gla- sive recent sea-ice retreat; however, recent changes in ciers because of their flat surfaces. The larger glacier was its glaciers are unknown and climateeoceaneglacier more favorable for snow accumulation because snow on interactions in this area have not been considered. The the small glaciers was blown away by wind. present study describes the mass balance change in a glacier on Bennett Island in the De Long Islands and 3. Long-term climate change in the vicinity of the climate change in the vicinity since the 1960s. De Long Islands 2. Study area The De Long Islands are located in a remote area in which long-term meteorological conditions are poorly Northeast of the New Siberian Islands, the De Long known. This section describes air temperature and Islands include five islands located within precipitation data since 1940 for Kotelnj and the De 75450e77150N and 148e158E. Fifty percent of the Long Islands. land area of the islands is covered by glaciers (Fig. 1). The glaciers exist on three islands, Bennett, Henrietta, 3.1. Air temperature and Jeannette, where glaciers cover almost one-half of their total area (172.2 km2). The glacierized area of each Meteorological observations have been conducted island is shown in Table 1. Bennett Island (76.4N, at Kotelnj (76.0N, 137.9E), near Bennett Island, Fig. 1. Location of (A) Kotelnj climate station, (B) Bennett Island, (C) Henrietta Island (D) Jeannette Island, (E) Zhokhov Island. 88 K. Konya et al. / Polar Science 8 (2014) 86e95 Table 1 (Fig. 3),andthewarmingtrendcontinuedintothe Glaciers areal change (*Verkulich et al., 1992; **Yabuki, in prep). 2000s. This trend was not seen in the summer (June, Island Glacier Glacier Glacier Difference July, August: JJA) mean temperature before 1980. area area area area of glacier 2 2 The summer mean temperature started to increase in (km )* 1951 (km ), 1987 2010 area (%) the 1990s and then increased rapidly in the 2000s (WGI) (km2)* (km2)** 1987e2010 (Fig. 3). Bennett 156.2 72.0 65.87 57.9 19.6 Henrietta 13.6 9.1 e 5.3 41.8 Jeannette 2.4 0.4 e 0.2 50.0 3.2. Precipitation Total 172.2 81.5 e 63.4 22.2 Fig. 4 shows the annual precipitation (Januar- yeDecember) and precipitation as snow in the mass since 1937. Fig. 3 shows the annual and summer mean balance year (SeptembereAugust), when monthly air air temperatures at Kotelnj. The air temperatures at temperatures are below freezing, which is thought to Kotelnj in the 1960s were the coldest since the 1930s; contribute accumulation as snowfall to the glacier mass the other regions were also cold in the 1960s. The balance. Both measures of precipitation show a decadal means for the 1960s and 2000s were decreasing trend, although precipitation in the Arctic is À15.4 CandÀ13.6 C, respectively, and the differ- generally increasing (e.g., Kattsov and Walsh, 2000; ence between these means is 1.8 C. The rate of Serreze and Hurst, 2000). Solid precipitation, espe- À warming in the 1990s was as rapid as 0.051Cy 1 cially, decreased drastically after 2000. Fig. 2. Glacier distributions in De Long Islands. (A) Bennett Island, (B) Henrietta Island, and (C) Jeannette Island based on the “World Atlas of Snow and Ice Resources” (1997) (above). (D) Altitude distribution of glaciers in Bennett Island described in the “World Atlas of Snow and Ice Resources.” The line 3e4 in the figure (A) is the cross profile on which stakes are set along. K. Konya et al. / Polar Science 8 (2014) 86e95 89 Table 2 Description of glaciers and mass balance of glaciers in Bennett Island in 1986/1987 (After Verkulich et al., 1992). Glacier Area, (km2) Altitudinal range, (m asl) Maximum depth, (m) Bw, (mm) Bs, (mm) Ba, (mm) Toll 55.5 0e380 160e170 210 À513 À303 De Long West 1.17 360e420 40e45 119 À350 À231 De Long East 5.16 240e340 40 105 À346 À241 Maliy 4.04 160e210 40e50 113 À298 À185 4. Climate variability around Bennett Island 4.1. Air temperature The climatic variability of the De Long Islands and Meteorological observations have been conducted vicinity was assessed to estimate the amplitude of the at Kotelnj (76.0N, 137.9E), next to Bennett Island, variability before using the data to calculate the mass since 1937, at Zhokhov Island from 1955 to 1993, and balance of Toll Glacier. Few climate stations exist in at Henrietta Island from 1955 to 1957 (Table 3). The the De Long Islands, and some of these operated for distances between Kotelnj, Zhokhov, and Henrietta only a short period.