基于CryoSat-2测高数据的南极局部地区DEM的建立与精度评定

南极数字高程模型(DEM)是南极冰盖变化研究的基础数据,在我国南极重点考察地区Dome A及中山站至Dome A考察断面,利用新一代测高卫星CryoSat-2,对常用的几种插值方法如反距离加权、克里金、径向基函数、局部多项式和最近邻点插值方法的插值精度进行交叉比较,结果显示克里金插值方法的精度最高。利用中国第21次南极科学考察队采集的GPS数据,对克里金插值方法生成的两个区域的DEM精度进行验证。结果表明,坡度较小的Dome A区域DEM精度较高,平均高差为1.248 m,标准差为0.51 m;坡度较大的中山站至Dome A断面区域DEM精度较低,平均高程差达到3.87 m,标准差为9.358 m。

DEM Development and Precision Analysis in Two Local Areas of Antarctica,Using CryoSat-2 Altimetry Data

The Antarctic ice sheet plays a major role in studies of global climate change and sea-level rise, and digital elevation models (DEMs) are of great importance in geoscience studies of Antarctica. The interpolation method is one of the key factors to the accuracy of DEM. Five interpolation methods including inverse distance weighted, Kriging, radial basis functions, local polynomial, and Nearest Neighbor methods were used to develop DEMs for the Dome A area and the transect from Zhongshan station to Dome A using CryoSat-2 satellite altimetry data. A cross validation method was applied to evaluate the accuracy;the results indicate that Kriging method is the best of the five methods. Two DEMs for the two areas were generated by the Kriging interpolation method with CryoSat-2 data. The accuracy of two DEMs was assessed by GPS data from the 21st Chinese National Antarctic Research Expedition (CHINARE). The results show that the DEM of Dome A area has higher reliability with a bias of 1.248 m and standard deviation of 0.51 m. While in the steeper area in the Zhongshan station to Dome A transect, the accuracy of the DEM was low, the bias was 3.87 m and the standard deviation was 9.358 m.