基于CryoSat-2雷达高度计数据的南极内陆冰盖高程变化与物质平衡

南极冰盖对海平面影响巨大，高程变化测量是南极物质平衡监测的重要手段。采用欧空局CryoSat-2雷达高度计数据，通过提取卫星升降轨的地面交叉点，监测了南极内陆冰盖的高程变化（物质平衡）。结果表明，后向散射能量对Ku波段的CryoSat-2雷达高度计的高程数据具有一定的影响，经后向散射能量校正后，时间序列上的高程变化变得平缓，高程变化与已有的降雪数据相比，更加符合实际情况。2010年11月至2017年11月南极内陆冰盖高程变化趋势为（-1.1±0.2）cm·a^-1。西南极的Kamb冰流高程变化率为（38.7±1.1）cm·a^-1，Moeller冰流高程变化率为（-10.3±1.2）cm·a^-1，部分Thwaites冰川区域高程变化率为（-13.4±1.8）cm·a^-1，东南极的Wilkes Land出现高下降区，最高达-20 cm·a^-1。Dronning Maud Land虽然出现变化异常的点，但整体并没有显著的高程变化。南极内陆冰盖质量变化为（-10.6±6.2）Gt·a^-1，整体上南极内陆冰盖质量变化平缓，部分区域变化较大，Kamb冰流达到（17.9±0.5）Gt·a^-1，Moeller冰流达到（-3.4±0.4）Gt·a^-1，部分Thwaites冰川区达到（-3.7±0.5）Gt·a^-1。

Change of surface elevation and mass balance in Antarctic ice sheet based on CryoSat-2 radar altimeter data

Antarctic ice sheet is one of the dominate factors in Global sea level rise. Measuring surface elevation changes is one of the important approaches to monitor ice mass balance in Antarctica. Based on the European Space Agency (ESA) CryoSat-2 radar altimeter data, elevation changes of Antarctic inland ice sheet (ice sheet mass balance) is monitored by extracting the ground crossovers between ascending satellite tracks and descending satellite tracks. It was found that the backscattered power influences elevation measurements of Ku-band CryoSat-2 radar altimeter. As this backscatter correction is applied, the elevation changes time series are smoothed, elevation changes compared with available snowfall data, which accords better with practical senses. From November 2010 to November 2017, overall trend of elevation changes in Antarctic inland ice sheet was (-1.1±0.2) cm·a^-1. Elevation change rate were (38.7±1.1) cm·a^-1 in Kamb ice stream of West Antarctica, (-10.3±1.2) cm·a^-1 in Moeller ice stream, and (-13.4±1.8) cm·a^-1 in some areas of Thwaites Glacier region, respectively. There was a significant descent area in Wilkes Land of East Antarctica, with a maximum elevation change rate of -20 cm·a^-1. In Dronning Maud Land, there was no significant elevation change, except for a few abnormal points. There were no abrupt mass fluctuations across Antarctic inland ice sheet, with an overall change rate of (-10.6±6.2) Gt·a^-1. There were a few exceptions in some areas: change rate of mass reached (17.9±0.5) Gt·a^-1 in Kamb Ice Stream, (-3.4±0.4) Gt·a^-1 in Moeller Ice Stream, and (-3.7±0.5) Gt·a^-1 in some areas of Thwaites Glacier, respectively.