气候变化领域集成服务门户(CCPortal): Seasonal monitoring of melt and accumulation within the deep percolation zone of the Greenland Ice Sheet and comparison with simulations of regional climate modeling

CCPortal

DOI	10.5194/tc-12-1851-2018
	Seasonal monitoring of melt and accumulation within the deep percolation zone of the Greenland Ice Sheet and comparison with simulations of regional climate modeling
	Heilig A.; Eisen O.; MacFerrin M.; Tedesco M.; Fettweis X.
发表日期	2018
ISSN	19940416
卷号	12 期号:6
英文摘要	Increasing melt over the Greenland Ice Sheet (GrIS) recorded over the past several years has resulted in significant changes of the percolation regime of the ice sheet. It remains unclear whether Greenland's percolation zone will act as a meltwater buffer in the near future through gradually filling all pore space or if near-surface refreezing causes the formation of impermeable layers, which provoke lateral runoff. Homogeneous ice layers within perennial firn, as well as near-surface ice layers of several meter thickness have been observed in firn cores. Because firn coring is a destructive method, deriving stratigraphic changes in firn and allocation of summer melt events is challenging. To overcome this deficit and provide continuous data for model evaluations on snow and firn density, temporal changes in liquid water content and depths of water infiltration, we installed an upwardlooking radar system (upGPR) 3.4m below the snow surface in May 2016 close to Camp Raven (66.4779° N, 46.2856° W) at 2120ma.s.l. The radar is capable of quasi-continuously monitoring changes in snow and firn stratigraphy, which occur above the antennas. For summer 2016, we observed four major melt events, which routed liquid water into various depths beneath the surface. The last event in mid-August resulted in the deepest percolation down to about 2.3m beneath the surface. Comparisons with simulations from the regional climate model MAR are in very good agreement in terms of seasonal changes in accumulation and timing of onset of melt. However, neither bulk density of near-surface layers nor the amounts of liquid water and percolation depths predicted by MAR correspond with upGPR data. Radar data and records of a nearby thermistor string, in contrast, matched very well for both timing and depth of temperature changes and observed water percolations. All four melt events transferred a cumulative mass of 56 kgm-2 into firn beneath the summer surface of 2015. We find that continuous observations of liquid water content, percolation depths and rates for the seasonal mass fluxes are sufficiently accurate to provide valuable information for validation of model approaches and help to develop a better understanding of liquid water retention and percolation in perennial firn. © Author(s) 2018.
学科领域	accumulation; climate modeling; comparative study; firn; meltwater; monitoring; percolation; pore space; radar; regional climate; seasonal variation; simulation; water retention; Arctic; Greenland; Greenland Ice Sheet
语种	英语
scopus关键词	accumulation; climate modeling; comparative study; firn; meltwater; monitoring; percolation; pore space; radar; regional climate; seasonal variation; simulation; water retention; Arctic; Greenland; Greenland Ice Sheet
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/119139
作者单位	Department of Earth and Environmental Sciences, LMU, Munich, Germany; Alfred Wegener Institute Helmholtz-Centre for Polar and Marine Research, Bremerhaven, Germany; Department of Geosciences, University of Bremen, Bremen, Germany; Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, United States; Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, United States; NASA Goddard Institute of Space Studies, New York, United States; Department of Geography, University of Liège, Liège, Belgium
推荐引用方式 GB/T 7714	Heilig A.,Eisen O.,MacFerrin M.,et al. Seasonal monitoring of melt and accumulation within the deep percolation zone of the Greenland Ice Sheet and comparison with simulations of regional climate modeling[J],2018,12(6).
APA	Heilig A.,Eisen O.,MacFerrin M.,Tedesco M.,&Fettweis X..(2018).Seasonal monitoring of melt and accumulation within the deep percolation zone of the Greenland Ice Sheet and comparison with simulations of regional climate modeling.Cryosphere,12(6).
MLA	Heilig A.,et al."Seasonal monitoring of melt and accumulation within the deep percolation zone of the Greenland Ice Sheet and comparison with simulations of regional climate modeling".Cryosphere 12.6(2018).