Vertical bedrock shifts reveal summer water storage in Greenland ice sheet

• 成果类型: Article
• 署名作者: Ran, Jiangjun; Ditmar, Pavel; van den Broeke, Michiel R.; Liu, Lin; Klees, Roland; Khan, Shfaqat Abbas; Moon, Twila; Li, Jiancheng; Bevis, Michael; Zhong, Min; Fettweis, Xavier; Liu, Junguo; Noel, Brice; Shum, C. K.; Chen, Jianli; Jiang, Liming; van Dam, Tonie
• 署名单位: Southern University of Science & Technology; Delft University of Technology; Utrecht University; Chinese University of Hong Kong; Technical University of Denmark; University of Colorado System; University of Colorado Boulder; Central South University; Wuhan University; Wuhan University; University System of Ohio; Ohio State University; Sun Yat Sen University; University of Liege; North China University of Water Resources & Electric Power; North China University of Water Resources & Electric Power; Hong Kong Polytechnic University; Hong Kong Polytechnic University; Hong Kong Polytechnic University; Chinese Academy of Sciences; Innovation Academy for Precision Measurement Science & Technology, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; Utah System of Higher Education; University of Utah
• 刊物名称: Nature
• ISSN/ISSBN: 0028-5766
• DOI: 10.1038/s41586-024-08096-3
• 发表日期: 2024-11-07
• 页码: 1-+
• 关键词: meltwater storage; mass-balance; subglacial drainage; sea-level; surface; firn; MODEL; displacements; acceleration; RESOURCES

摘要

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 Earth(1-5). 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 rise(6).