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A high-resolution reconstruction of Storglaciären mass balance back to 1780/81 using tree-ring data and circulation indices |
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| Authors: | Hans W Linderholm Peter Jansson |
| Institution: | a Regional Climate Group, Department of Earth Sciences, Göteborg University, SE-405 30 Göteborg, Sweden b Tarfala Research Station, Department of Physical Geography and Quaternary Geology, Stockholm University, SE-106 91 Stockholm, Sweden c Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, 46 Zhongguancun Nandajie, Haidian, Beijing 100081, China |
| Abstract: | Storglaciären in northernmost Sweden has the world's longest ongoing continuous mass-balance record, starting in 1946. To extend this mass-balance record, we have reconstructed summer (bS) and winter (bW) mass balances separately back to the mass balance year 1780/81 with annual resolution. We used tree-ring data for bS and a set of circulation indices, based on the sea-level pressure, for bW. Both proxies have correlation coefficients with respective mass balance components of ca. 0.7. The reconstructed net balance (bN) of Storglaciären was well correlated to the observations during 1946-1980 (r = 0.8, p < 0.05). Our reconstruction agrees well with previously obtained results of northern Sweden glacier variability, where the predominantly positive bN years between 1890 and 1910 correspond to the well documented post-Little Ice Age advance of Storglaciären. Furthermore, the results suggest that bS, as a function of summer temperatures, is more important than bW in determining the bN, which is contrary to glaciers in the maritime parts of western Scandinavia. In general, bN has been negative over the last 220 yr, suggesting a predomination of continental conditions over northern Sweden. However, the influence of bW increased in the late twentieth century, indicating a shift to a more oceanic climate regime. |
| Keywords: | Mass-balance reconstruction Tree rings Circulation indices Storglaciä ren Northern Sweden |
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