基于机载冰雷达探测和三维各向异性耦合冰盖模式的东南极伊丽莎白公主地冰下水热环境研究

冰下水热环境特征主导了冰盖在大尺度上的动力学行为，从而在预测冰盖对海平面变化的影响方面扮演了重要的角色。目前由于观测数据的缺少和限制，我们对东南极伊丽莎白公主地的了解很少，特别是对该地区的冰下水热环境缺乏基本的认识。本研究基于CHINARE32次(2015/2016)以来对东南极伊丽莎白公主地进行的多次机载冰雷达探测所获取的航空冰雷达数据，以及今后南极考察获得的冰雷达图像，对冰下回波信号和内部等时层进行提取；计算冰面高程、冰厚,获得冰下地形高程；通过回波信号和内部等时层信息提取的冰晶组构信息，形成伊丽莎白公主地冰盖表面和冰下环境的基础数据集。然后基于数据集改进基于ELMER/ICE的三维各向异性耦合模式，进行参数化方案重建，定量计算该地区的内部温度分布、速度分布。与冰雷达数据结合诊断冰下水热环境异常区域，给出冰下暖冰/冷冰分布区、复结冰分布区、冰下湖分布和潜在的冰下水系分布。

Subglacial conditions dominate a large extent the dynamical behavior of ice sheets, and hence play an important role in predicting the contribution of t ice sheets to sea level changes. At present，as a result of the lack of geophysical data，little is known about local and large-scale subglacial conditions of Princess Elizabeth Land in the East Antarctic ice sheet, and the subglacial temperature and hydrology are poorly understood. In this study, we use the ice radar data, from airborne radio echo sounding in Princess Elizabeth Land of the East Antarctic ice sheet, since CHINARE 32 (2015/2016), to collect reflectors and internal isochrones. Using the reflectors, we calculate ice surface elevation, ice thickness and subglacial topography, and infer ice crystal fabric structure from the internal isochrones. Applying the data, we construct the dataset of the ice surface and subglacial conditions covering Princess Elizabeth Land. Then，we utilize the observed ice anisotropic fabric in a three-dimensional, thermomechanically coupled full-Stokes model to simulate subglacial temperature and hydrology, improving the ELMER/ICE model. We also reconstruct the parameterization scheme of the model, and simulate the temperature and velocity fields. Finally, combining with the radar dataset and the simulated result ,we diagnose the area with abnormal hydrothermal condition and distinguish the area of warm /cold ice, refreeze on ice，subglacial lakes, and subglacial water systems.