气候变化领域集成服务门户(CCPortal): Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland

CCPortal

DOI	10.5194/tc-9-2163-2015
	Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland
	Charalampidis C.; Van As D.; Box J.E.; Van Den Broeke M.R.; Colgan W.T.; Doyle S.H.; Hubbard A.L.; MacFerrin M.; Machguth H.; P. Smeets C.J.P.
发表日期	2015
ISSN	19940416
卷号	9 期号:6
英文摘要	We present 5 years (2009-2013) of automatic weather station measurements from the lower accumulation area (1840 m a.s.l.-above sea level) of the Greenland ice sheet in the Kangerlussuaq region. Here, the summers of 2010 and 2012 were both exceptionally warm, but only 2012 resulted in a strongly negative surface mass budget (SMB) and surface meltwater run-off. The observed run-off was due to a large ice fraction in the upper 10 m of firn that prevented meltwater from percolating to available pore volume below. Analysis reveals an anomalously low 2012 summer-averaged albedo of 0.71 (typically ∼ 0.78), as meltwater was present at the ice sheet surface. Consequently, during the 2012 melt season, the ice sheet surface absorbed 28 % (213 MJ m-2) more solar radiation than the average of all other years. A surface energy balance model is used to evaluate the seasonal and interannual variability of all surface energy fluxes. The model reproduces the observed melt rates as well as the SMB for each season. A sensitivity analysis reveals that 71 % of the additional solar radiation in 2012 was used for melt, corresponding to 36 % (0.64 m) of the 2012 surface lowering. The remaining 64 % (1.14 m) of surface lowering resulted from high atmospheric temperatures, up to a +2.6 °C daily average, indicating that 2012 would have been a negative SMB year at this site even without the melt-albedo feedback. Longer time series of SMB, regional temperature, and remotely sensed albedo (MODIS) show that 2012 was the first strongly negative SMB year, with the lowest albedo, at this elevation on record. The warm conditions of recent years have resulted in enhanced melt and reduction of the refreezing capacity in the lower accumulation area. If high temperatures continue, the current lower accumulation area will turn into a region with superimposed ice in coming years. © 2015 Author(s).
学科领域	accumulation; albedo; energy balance; energy flux; ice sheet; meltwater; MODIS; sensitivity analysis; solar radiation; surface area; time series; Arctic; Greenland; Kangerlussuaq Fjord; West Greenland
语种	英语
scopus关键词	accumulation; albedo; energy balance; energy flux; ice sheet; meltwater; MODIS; sensitivity analysis; solar radiation; surface area; time series; Arctic; Greenland; Kangerlussuaq Fjord; West Greenland
来源期刊	Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/119784
作者单位	Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, Copenhagen K, 1350, Denmark; Department of Earth Sciences, Uppsala University, Villavägen 16, Uppsala, 75236, Sweden; Institute for Marine and Atmospheric Research (IMAU), Utrecht University, P.O. Box 80005, Utrecht, 3508TA, Netherlands; Department of Earth and Space Sciences and Engineering, York University, 4700 Keele Street, Toronto, M3J1P3, Canada; Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth, SY233DB, United Kingdom; Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geology, University of Tromsø, Dramsveien 201, Tromsø, 9037, Norway; Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder, Boulder, CO 80309, United States; Arctic Technology Centre (ARTEK), Technical University of Denmark, Brovej byg. 118, Kgs. Lyngby, 2800, Denmark
推荐引用方式 GB/T 7714	Charalampidis C.,Van As D.,Box J.E.,et al. Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland[J],2015,9(6).
APA	Charalampidis C..,Van As D..,Box J.E..,Van Den Broeke M.R..,Colgan W.T..,...&P. Smeets C.J.P..(2015).Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland.Cryosphere,9(6).
MLA	Charalampidis C.,et al."Changing surface-atmosphere energy exchange and refreezing capacity of the lower accumulation area, West Greenland".Cryosphere 9.6(2015).