基于卫星重力和测高数据的格陵兰冰盖质量变化分析

Analysis of Greenland Ice Sheet mass changes using satellite gravity and altimetry data

格陵兰冰盖全部融化将导致全球海平面上升7m,因此准确估计格陵兰冰盖质量变化过程对理解其对全球气候变化响应和反馈作用具有重要意义。基于Gravity Recovery and Climate Experiment(GRACE)卫星及后继卫星GRACE-FollowOn(GRACE-FO)提供的近20年的月时变重力场数据,以及EuropeanRemote Sensing(ERS-2)、Envisat和CryoSat-2等卫星测高数据,本文对比分析了2002年4月-2020年12月格陵兰冰盖质量变化特征。研究结果表明:(1)卫星重力点质量模型与卫星测高产品估计的质量变化趋势空间分布较为一致,均表明格陵兰冰盖边缘低海拔区域质量亏损严重而内部高原存在质量累积。(2) 2002-2020年格陵兰质量损失对全球平均海平面变化贡献为0.73±0.01mm·a^(-1)。(3)格陵兰冰盖西南部和西北部对海平面变化的贡献占格陵兰总贡献量的43.69%,为主要的海平面上升贡献区。(4)格陵兰冰盖流域尺度的分析表明,Goddard Space Flight Center(GSFC)点质量模型与卫星测高估计的结果更为一致。

Global sea levels would rise by 7 m,if the Greenland Ice Sheet(GrIS)were to melt completely.Therefore,an accurate estimate of the mass change over the GrIS is of great importance for the understanding of the reaction of the GrIS to global climate change.Using nearly 20 years of monthly gravity field data provided by the Gravity Recovery and Climate Experiment(GRACE)and GRACE-Follow On(GRACE-FO)mission,as well as satellite altimetry data from European Remote Sensing(ERS-2),Envisat,and CryoSat-2,this study comparatively analyzes the characteristics of GrIS mass change between April 2002 and December 2020.Results demonstrate that:(1)the spatial distributions of mass change trends estimated by GRACE/GRACE-FO mascon solutions and satellite altimetry data are relatively consistent;both indicate severe mass loss in the low-elevation regions around the GrIS margin and a mass accumulation in the inner plateau.(2)The mass loss of the GrIS contributed to a global mean sea level change of 0.73±0.01 mm·a^(−1) between 2002 and 2020.(3)The southwest and northwest regions of the GrIS contributed to 43.69% of the total sea level change,making them the primary contributors to sea level rise.(4)We compared basin-scale mass change estimates from the satellite altimetry with those from mascon solutions and found that the Goddard Space Flight Center(GSFC)mascon solutions is the closest.