基于ICESat轨道交叉点分析的东南极Lambert-Amery系统当前高程变化特征分析

Recent elevation changes on the Lambert-Amery system in East Antarctica from ICESat crossover analysis

南极冰盖物质平衡仍然是全球海平面变化估计的最大不确定因素.本文使用2003～2007年ICESat/GLAS获取的高精度冰盖测高数据,利用我们开发的高精度高程变化提取程序,首次获取了东南极最大冰流系统——Lambert-Amery地区在ICESat卫星轨道交叉点处的高程变化序列.依据冰川动力学原理,对该流域进行详细划分,并在此基础上利用回归模型研究各子区域内高程年际变化特征.对该区域的研究有以下新的认识:(1)除Amery冰架区域(AIS)外,其他区域高程年际变化呈正增长;(2)各子区域高程的年际变化特征呈现显著的区域变化特征,AIS和MGLup的年际变化分别为-6.1 cm/a和6.6 cm/a.(3)流域西侧的高程变化是东部的2～3倍.研究第一次以高密度和高时间分辨率获取了该区域高程变化的时间序列,并采用回归模型详细分析了各子区域高程的年际变化特征.

Mass balance of Antarctic ice sheet remains the largest source of uncertainty in estimation of global sea level change. Depending on our developed procedure on the basis of crossover analysis method, the current short-term rates of elevation change in Lambert-Amery system have been evaluated using ICESat/GLAS altimetry data over the period 2003 - 2007 comprising 10 ICESat observation periods. The interannual variability of elevation has been obtained in sub-regions of Lambert-Amery System （LAS）, which are defined and calibrated on principle of glacier dynamics, using regression analysis method. We get the new conclusions shown as follows： （1） the elevations are almost increasing in all sub-regions except for AIS subegion; （2） It is very obvious that there are largely regional variations of elevation m the supregions, the largest interannual variability of elevation in AIS and MGLup are -6.1 cm/a and 6.6 cm/a respectively; （3）Interannual variation of elevation in western LAS is 2-3 times that of the eastern part. This is the first time to get the series of elevation change in LAS with highdensity and high-precision and its interannual variability in the sub-regions are fully analyzed.