李斐， 袁乐先， 张胜凯， 杨元德， 鄂栋臣， 郝卫峰

武汉大学中国南极测绘研究中心， 武汉　430079



利用ICESat数据解算南极冰盖冰雪质量变化

李斐， 袁乐先， 张胜凯*， 杨元德， 鄂栋臣， 郝卫峰

武汉大学中国南极测绘研究中心， 武汉430079

摘要南极冰盖冰雪质量变化反映了全球气候变化，并且直接影响着全球海平面变化.ICESat测高卫星的主要任务之一就是要确定南北两极冰盖的质量变化情况并评估其对全球海平面变化的影响.本文利用2003年10月至2008年12月的ICESat测高数据，针对南极DEM分辨率有限的特殊性，通过求解坡度改正值，解决重复轨道地面脚点不重合的问题，计算了南极大陆(86°S以北区域，后文所述南极冰盖均不包括86°S以南区域)在这5年里的冰雪质量变化情况，得到东南极冰盖的质量变化为-18±20 Gt/a，西南极-26±6 Gt/a，南极冰盖的冰雪质量变化为-44±21 Gt/a，对全球海平面上升的影响约为0.12 mm·a-1.解算结果表明，南极冰盖质量亏损主要集中在西南极阿蒙森海岸附近冰川以及东南极波因塞特角区域.

关键词南极冰盖； 物质平衡； ICESat； 重复轨道

There are two methods for calculating the mass change of the Antarctic ice sheet using altimetry satellite data: cross point method and repeat track method. The repeat track method seems more commonly applied, in which the unmeasured topography between near repeat tracks need to be considered when comparing elevations from different tracks. We applied slope corrections between the different tracks to restrict all the different tracks to one reference track, and then calculated the surface elevation changes of the Antarctic ice sheet. The mass change of the Antarctic ice sheet was estimated by using the ice density model.

The mass balance of Antarctic ice sheet was calculated to be -44±21 Gt/a including -26±6 Gt/a for West Antarctica and -18±20 Gt/a for East Antarctica using 5-year ICESat altimetry data from October 2003 to December 2008, and the contribution of the Antarctic ice sheet loss to global sea level is about 0.12 mm·a-1.

The comparison of our results with previous work shows a strong agreement. The results show that the mass losing of the Antarctic ice sheet is mainly concentrated near the Amundsen Sea in West Antarctica and Poinsett Cape in East Antarctica.

1引言

研究表明，全球平均海平面正处于加速上升的状态(Nicholls and Cazenave, 2010).不考虑海水的热膨胀效应，冰雪消融是引起全球海平面上升的主要原因，在接下来的几十年内，南北极冰盖的变化将是导致全球海平面上升的最大不确定性因素(Meier et al., 2007).南北极冰盖正处于加速消融状态(Chen et al., 2009; Velicogna, 2009; Luo et al., 2012)，使得冰盖物质平衡对全球海平面的影响占据越来越重要的地位.Rignot等(2011)指出南北极两大冰盖可能会成为导致……