气候变化领域集成服务门户(CCPortal): Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica

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DOI	10.5194/tc-11-2675-2017
	Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica
	Berger S.; Drews R.; Helm V.; Sun S.; Pattyn F.
发表日期	2017
ISSN	19940416
卷号	11 期号:6
英文摘要	Ice shelves control the dynamic mass loss of ice sheets through buttressing and their integrity depends on the spatial variability of their basal mass balance (BMB), i.e. the difference between refreezing and melting. Here, we present an improved technique-based on satellite observations-to capture the small-scale variability in the BMB of ice shelves. As a case study, we apply the methodology to the Roi Baudouin Ice Shelf, Dronning Maud Land, East Antarctica, and derive its yearly averaged BMB at 10ĝm horizontal gridding. We use mass conservation in a Lagrangian framework based on high-resolution surface velocities, atmospheric-model surface mass balance and hydrostatic ice-thickness fields (derived from TanDEM-X surface elevation). Spatial derivatives are implemented using the total-variation differentiation, which preserves abrupt changes in flow velocities and their spatial gradients. Such changes may reflect a dynamic response to localized basal melting and should be included in the mass budget. Our BMB field exhibits much spatial detail and ranges from ĝ'14.7 to 8.6ĝmĝaĝ'1 ice equivalent. Highest melt rates are found close to the grounding line where the pressure melting point is high, and the ice shelf slope is steep. The BMB field agrees well with on-site measurements from phase-sensitive radar, although independent radar profiling indicates unresolved spatial variations in firn density. We show that an elliptical surface depression (10ĝm deep and with an extent of 0.7ĝkm × 1.3ĝkm) lowers by 0.5 to 1.4ĝmĝaĝ'1, which we tentatively attribute to a transient adaptation to hydrostatic equilibrium. We find evidence for elevated melting beneath ice shelf channels (with melting being concentrated on the channel's flanks). However, farther downstream from the grounding line, the majority of ice shelf channels advect passively (i.e. no melting nor refreezing) toward the ice shelf front. Although the absolute, satellite-based BMB values remain uncertain, we have high confidence in the spatial variability on sub-kilometre scales. This study highlights expected challenges for a full coupling between ice and ocean models. © Author(s) 2017.
学科领域	detection method; grounding line; ice shelf; ice thickness; ice-ocean interaction; mass balance; radar; spatial variation; TanDEM-X; Antarctica; East Antarctica; Queen Maud Land; Roi Baudouin Ice Shelf
语种	英语
scopus关键词	detection method; grounding line; ice shelf; ice thickness; ice-ocean interaction; mass balance; radar; spatial variation; TanDEM-X; Antarctica; East Antarctica; Queen Maud Land; Roi Baudouin Ice Shelf
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/119305
作者单位	Laboratoire de Glaciologie, Université Libre de Bruxelles, Brussels, Belgium; Department of Geosciences, University of Tübingen, Tübingen, Germany; Glaciology Section, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
推荐引用方式 GB/T 7714	Berger S.,Drews R.,Helm V.,et al. Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica[J],2017,11(6).
APA	Berger S.,Drews R.,Helm V.,Sun S.,&Pattyn F..(2017).Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica.Cryosphere,11(6).
MLA	Berger S.,et al."Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica".Cryosphere 11.6(2017).