基于Elmer/Ice冰盖模式的南极Gamburtsev山脉Lambert冰流区域的数值模拟研究

NUMERICAL SIMULATIONS OF EAST ANTARCTIC ICE SHEET BASED ON THE ELMER/ICE MODEL

在全球变暖的背景下,东南极冰盖显著地出现降雪增多冰厚增大的现象,然而由于有关东南极冰盖的观测数据相对缺乏,因而很难对东南极冰盖大范围的冰盖动力学、热力学状态细节进行整体性评估。Dome A到中山站断面是横穿南极冰盖计划的核心断面之一。该断面穿越的兰伯特(Lambert)冰川上游、甘布尔采夫(Gamburtsev)冰下山脉和Dome A区域是南极科学研究的热点区域,因此具有重要的研究价值。本研究使用已多次在南极冰盖有过成功模拟应用的三维有限元冰盖模式Elmer/Ice,对该区域的内部温度场和速度场进行了模拟,得到了冰盖的流速场和温度场数据,并将模拟数据与传统估测数据进行了对比,发现两者在总体趋势上吻合。研究表明,该研究区域冰盖的底部温度大部分达到了压力熔点,只有少部分靠近内陆的冰盖底部未达到;在冰盖内陆区域,水平速度场非常小,在靠近冰架区域时,水平速度场突然增大,而垂直速度场只有在冰下地形发生显著波动时,出现显著变化。在此基础上,对Elmer/Ice冰盖模式的应用前景和需改进的方面进行了探讨。

Within the context of global warming, the thickness of the East Antarctic ice sheet has increased according to recent observations. However, the lack of observations means it is difficult to perform detailed research on the dynamics and thermodynamics of the ice sheet. The section from Dome A to the Zhongshan station, which is an important section of the International Trans-Antarctic Scientific Expedition, includes many important research sites, e.g., the upstream of the Lambert Glacier, the Gamburtsev Mountains, and Dome A. This study used a three-dimensional finite element model to obtain the inland velocity and temperature fields of the ice sheet. It was found that the modeled and observational data were identical. The bottom temperature of most parts of the ice sheet within this area has reached the pressure melting point. The velocity of the inland ice sheet is small. Near the ice shelf, the horizontal velocity increases abruptly, while the vertical velocity changes only where the bottom morphology changes rapidly. The prospects for further application of the Elmer/Ice model and areas requiring improvement are discussed.