DOI: 10.5194/tc-11-2675-2017
Scopus记录号: 2-s2.0-85035038628
论文题名: Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica
作者: Berger S ; , Drews R ; , Helm V ; , Sun S ; , Pattyn F
刊名: Cryosphere
ISSN: 19940416
出版年: 2017
卷: 11, 期: 6 起始页码: 2675
结束页码: 2690
语种: 英语
英文关键词: 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
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. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/75474
Appears in Collections: 影响、适应和脆弱性 气候变化与战略
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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
Recommended Citation:
Berger S,, Drews R,, Helm V,et al. Detecting high spatial variability of ice shelf basal mass balance, Roi Baudouin Ice Shelf, Antarctica[J]. Cryosphere,2017-01-01,11(6)