气候变化领域集成服务门户(CCPortal): Importance of orography for Greenland cloud and melt response to atmospheric blocking

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DOI	10.1175/JCLI-D-19-0527.1
	Importance of orography for Greenland cloud and melt response to atmospheric blocking
	Hahn L.C.; Storelvmo T.; Hofer S.; Parfitt R.; Ummenhofer C.C.
发表日期	2020
ISSN	0894-8755
起始页码	4187
结束页码	4206
卷号	33 期号:10
英文摘要	More frequent high pressure conditions associated with atmospheric blocking episodes over Greenland in recent decades have been suggested to enhance melt through large-scale subsidence and cloud dissipation, which allows more solar radiation to reach the ice sheet surface. Here we investigate mechanisms linking high pressure circulation anomalies to Greenland cloud changes and resulting cloud radiative effects, with a focus on the previously neglected role of topography. Using reanalysis and satellite data in addition to a regional climate model, we show that anticyclonic circulation anomalies over Greenland during recent extreme blocking summers produce cloud changes dependent on orographic lift and descent. The resulting increased cloud cover over northern Greenland promotes surface longwave warming, while reduced cloud cover in southern and marginal Greenland favors surface shortwave warming. Comparison with an idealized model simulation with flattened topography reveals that orographic effects were necessary to produce area-averaged decreasing cloud cover since the mid-1990s and the extreme melt observed in the summer of 2012. This demonstrates a key role for Greenland topography in mediating the cloud and melt response to large-scale circulation variability. These results suggest that future melt will depend on the pattern of circulation anomalies as well as the shape of the Greenland Ice Sheet. © 2020 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
英文关键词	Climate models; Glaciers; High pressure effects; Anticyclonic circulation; Atmospheric blocking; Circulation anomalies; Cloud radiative effects; Greenland Ice Sheet; High-pressure condition; Large-scale circulation; Regional climate modeling; Topography; anticyclone; atmospheric blocking; atmospheric circulation; cloud radiative forcing; meltwater; orography; topography; Arctic; Greenland
语种	英语
来源期刊	Journal of Climate
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/171317
作者单位	Physical Oceanography Department, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Section for Meteorology and Oceanography, Department of Geosciences, University of Oslo, Oslo, Norway; School of Geographical Sciences, University of Bristol, Bristol, United Kingdom; Laboratory of Climatology, Department of Geography, University of Liège, Liège, Belgium; Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL, United States
推荐引用方式 GB/T 7714	Hahn L.C.,Storelvmo T.,Hofer S.,et al. Importance of orography for Greenland cloud and melt response to atmospheric blocking[J],2020,33(10).
APA	Hahn L.C.,Storelvmo T.,Hofer S.,Parfitt R.,&Ummenhofer C.C..(2020).Importance of orography for Greenland cloud and melt response to atmospheric blocking.Journal of Climate,33(10).
MLA	Hahn L.C.,et al."Importance of orography for Greenland cloud and melt response to atmospheric blocking".Journal of Climate 33.10(2020).