2024-10-29 オランダ・デルフト工科大学（TUDelft)
＜関連情報＞
- https://www.tudelft.nl/en/2024/citg/large-meltwater-accumulation-revealed-inside-greenland-ice-sheet
- https://www.nature.com/articles/s41586-024-08096-3
グリーンランド氷床における夏の貯水量を明らかにする岩盤の垂直移動 Vertical bedrock shifts reveal summer water storage in Greenland ice sheet
Jiangjun Ran,Pavel Ditmar,Michiel R. van den Broeke,Lin Liu,Roland Klees,Shfaqat Abbas Khan,Twila Moon,Jiancheng Li,Michael Bevis,Min Zhong,Xavier Fettweis,Junguo Liu,Brice Noël,C. K. Shum,Jianli Chen,Liming Jiang & Tonie van Dam
Nature Published:30 October 2024
DOI:https://doi.org/10.1038/s41586-024-08096-3
Abstract
The Greenland ice sheet (GrIS) is at present the largest single contributor to global-mass-induced sea-level rise, primarily because of Arctic amplification on an increasingly warmer Earth1,2,3,4,5. However, the processes of englacial water accumulation, storage and ultimate release remain poorly constrained. Here we show that a noticeable amount of the summertime meltwater mass is temporally buffered along the entire GrIS periphery, peaking in July and gradually reducing thereafter. Our results arise from quantifying the spatiotemporal behaviour of the total mass of water leaving the GrIS by analysing bedrock elastic deformation measured by Global Navigation Satellite System (GNSS) stations. The buffered meltwater causes a subsidence of the bedrock close to GNSS stations of at most approximately 5 mm during the melt season. Regionally, the duration of meltwater storage ranges from 4.5 weeks in the southeast to 9 weeks elsewhere. We also show that the meltwater runoff modelled from regional climate models may contain systematic errors, requiring further scaling of up to about 20% for the warmest years. These results reveal a high potential for GNSS data to constrain poorly known hydrological processes in Greenland, forming the basis for improved projections of future GrIS melt behaviour and the associated sea-level rise6.
