联合卫星重力、卫星测高和海洋资料研究全球海平面变化

Global Sea Level Variations Estimated from Satellite Altimetry,GRACE and Oceanographic Data

利用GRACE、卫星测高和海洋实测温盐数据,探讨了2003~2012年间全球海平面、比容海平面和海水质量等的变化特征,并讨论了南极冰盖和格陵兰冰盖消融对全球海平面变化的影响。全球海平面整体呈上升趋势,上升速度为2.72±0.07mm/a,且存在显著的空间分布特征。全球海平面、比容海平面和海水质量等的变化还具有显著的季节性特征,其中全球海平面变化的年周期振幅为4.6±0.3mm。使用经验正交函数分析(EOF)得到全球海平面和比容海平面的季节性变化在南北半球存在显著的差异,但海水质量季节性变化不存在这种差异。南极冰盖和格陵兰冰盖的消融速率分别为-75.7±12.3Gt/a和-124.1±2.9Gt/a,对海平面的长期趋势项贡献分别为0.21±0.03mm/a和0.34±0.01mm/a,仅占全球海水质量增加速度1.80±0.10mm/a的12%和19%,总计占31%,因此,两极冰盖质量消融并不是2003-2012年间海水质量增加的最主要因素。

In this paper,global sea level variations and the influence on the sea level rise from Antarctic ice sheet and Greenland ice sheet ablation from 2003 to 2012are estimated from satellite altimetry,GRACE and oceanographic data.From 2003 to 2012,global sea level rose with the rate at 2.72±0.07mm/a and spatial distribution characteristics estimated from altimetry.Ocean mass changes estimated from GRACE accounted for 66%of the sea level change,with the rate at 1.80±0.10mm/a,and steric sea level changes accounted for 34% of the sea level change with the rate at 0.93±0.05mm/a estimated from Argo and accounted for 19% of the sea level change with the rate at 0.51±0.03mm/a estimated from Ishii.Meanwhile,global sea level,steric sea level and oceanic mass variations had significant seasonal characteristics,with the annual cycle amplitude 4.6±0.3mm,4.1±0.2mm,3.6±0.1mm and 7.3±0.4mm,respectively,estimated from altimetry,Argo,Ishii and GRACE.Using empirical orthogonal function(EOF)analysis,we found significant seasonal differences existed between the northern and southern hemispheres in global sea level,steric sea level,but did not exist in oceanic mass changes.The rates of Antarctica ice sheet and Greenland ice sheet ablation were-75.7±12.3Gt/a and-124.1±2.9Gt/a from 2003 to 2012,respectively.And the correspondent global sea level rising rates were 0.21±0.03mm/a,0.34±0.01mm/a,which can only accounted for 12%and 19%,total up to only 31% of the ocean mass increase.So the melting of the polar ice sheet was not the most important factor in the increase of ocean mass from 2003 to 2012.