摘要
格陵兰冰盖是影响全球气候变化的重要因素之一,其微小变化会引起海平面的显著变化,因此定量研究其物质平衡具有重要的科学意义。利用最新发射的ICESat-2卫星激光测高数据(2018年11月至2019年9月),联合ICESat数据(2003年2月至2009年10月),估算2003年2月至2019年9月格陵兰冰盖物质平衡。首先通过交叉点法得到冰盖表面的高程变化,再根据积雪堆积、表面融化和动力变化等物理过程计算密度值,最后经过粒雪含量、冰后回弹和弹性回弹校正计算物质平衡,并针对不同的冰川水文流域进行空间差异性分析。结果表明:(1)2003—2019年格陵兰冰盖主体的平均高程变化为-11.27±0.83cm/yr;(2)高程2000 m以下的冰盖呈较大的消融趋势,高程最大消融速率为-6.0 m/yr,总体积变化速率为-206.0 km^(3)/yr,2000 m以上的冰盖呈上升趋势,高程最大累积率为1.1 m/yr,总体积变化率为14.2 km^(3)/yr;(3)校正后触地冰的总物质平衡为-195.2±13.1 Gt/yr,其中东南部和西北部流域消融量较大,仅有东北部流域呈累积趋势;(4)2003—2019年格陵兰温度整体处于上升趋势,最大变化率为0.8 K/yr,降水在东部和西北部呈下降趋势,最大变化率为-0.1 mm/yr,在一定程度上加速了冰盖消融。
The Greenland Ice Sheet is one of the important factors affecting global climate change.Minor changes in Greenland Ice Sheet can cause significant change in sea level.Thus,it is extremely essential to estimate the Greenland Ice Sheet mass balance quantitatively,which lays foundation for understanding global sea level rise and climate change.In this study,the latest ICESat-2 satellite laser altimetry data(November 2018 to September 2019)and the ICESat data(February 2003 to October 2009)are used to estimate Greenland Ice Sheet mass balance from February 2003 to September 2019.The elevation change of the Greenland Ice Sheet is obtained by crossover analysis.During the process of calculating mass balance,we have corrections for deformation of the Firn Air Content,Glacial Isostatic Adjustment,and Elastic Rebound,and the ice-column density is estimated by ice physical process parameters,such as snow accumulation,glacier surface melting,and glacier surface dynamic change.To further analyze the spatial variation of Greenland Ice Sheet mass balance,we compared the results of mass balance across the glacier hydrological basins.Results show:(1)The main body of the Greenland Ice Sheet from 2003 to 2019 is melting with a mean annual elevation change rate of about-11.27±0.83 cm/yr;(2)For ice sheet below 2000 m,the overall volume change rate is-206.0 km^(3)/yr,which indicates a relatively large ablation and the maximum ablation rate is-6.0 m/yr.In contrast,the ice sheet above 2000 m shows an accumulation trend.Its volume change rate is 14.2 km^(3)/yr,with the maximum accumulation rate of1.1 m/yr;(3)The total mass balance of Greenland Ice Sheet grounded-ice from 2003 to 2019 is-195.2±13.1 Gt/yr after correction.And the mass balance change has obvious regional variation.The southeastern and northwestern drainage basins show a large ablation trend,and the northeastern drainage basin is the only accumulation zone;(4)The annual mean temperature in Greenland Ice Sheet is rising at a rate of 0.8 K/yr during the period of 2003-2019,while its mean precipitation shows a downward trend especially in the east and northwest of Greenland Ice Sheet,with a maximum decreasing rate of-0.1 mm/yr.Hence,we can conclude that the accelerated melting pattern of Greenland Ice Sheet is due to the combined effect of the increasing annual mean temperature and decreasing annual mean precipitation in this area.
作者
李晴烁
柯长青
张杰
范宇宾
沈校熠
LI Qingshuo;KE Changqing;ZHANG Jie;FAN Yubin;SHEN Xiaoyi(School of Geography and Ocean Science,Nanjing University,Nanjing 210023,China;First Institute of Oceanography,Ministry of Natural Resources,People's Republic of China,Qingdao 266061,China)
出处
《地球信息科学学报》
CSCD
北大核心
2022年第3期558-571,共14页
Journal of Geo-information Science
基金
国家自然科学基金重点项目(41830105)。
