基于多源遥感数据与冰流物理模型的南极冰架冰川系统动态变化及其稳定性研究

The flow dynamics and mass balance of the Antarctic Ice Sheet are intricately linked to the global climate change and sea level rise. The dynamics of the ice shelf-glacial systems play significant roles in controlling the mass balance state of the Antarctic Ice Sheet, and the flow velocity fields of outlet glaciers and ice streams dictate the ice discharge rate from the ice sheet into the ocean system. The stability of the peripheral ice shelves is important to restrain and stabilize the ice discharge of the upstream outlet glaciers. It is crucial to quantitatively investigate the interrelationships between ice shelves and outlet glaciers. The previous studies regarding the flow dynamics of the outlet glaciers and ice shelves are limited to some specific sites over a few time periods. This research aims to derive the long-term time series ice velocity fields for the Larsen ice shelf-glacial system in Antarctic Peninsula and the Totten ice-shelf-glacial system in East Antarctica over the past half century, by integrating multi-source satellite images (including historical declassified intelligence satellite photographs, optical satellite images and radar satellite images) and utilizing the image-matching based feature tracking method. Based on the derived ice velocity time series, this research will analyze the spatio-temporal variability in ice flow patterns and identify the acceleration, deceleration and stable time periods for the different ice shelf-glacier systems. The relations between the flow velocity variations and the morphologic and structural changes of ice shelves will be analyzed. Besides, this research will build physically based ice flow models using the finite element numerical modeling method to 1) investigate the responsive mechanisms of tributary outlet glaciers to the dynamic changes of ice shelf thinning, ice shelf front retreat, mechanical weakening and disintegration; and 2) examine the relationship of the flow velocity fields with the internal stress structure, ice rheology and stability of ice shelves. The algorithms, software tools, and data products will benefit the cryosphere and glaciological research community and help polar scientists to conduct quantitative analysis and modeling of the Antarctic Ice Sheet.

南极冰盖的动态变化与物质平衡过程与全球气候变化以及海平面上升息息相关，冰架-冰川系统是南极冰盖的重要组成部分，流动速度是度量冰川动态变化以及物质平衡过程的重要参数。定量分析与模拟冰架-冰川的动态耦合机制对预测南极冰盖未来演化有着重要的意义。针对现有对于冰架-冰川系统流动变化的长期研究的空缺，本项目拟选择位于南极半岛的拉森冰架冰川系统以及位于东南极的托腾冰架冰川系统为研究区，以多源遥感数据（包括早期卫星解密影像、光学卫星影像以及雷达卫星影像）为基础，通过基于影像匹配的特征追踪法提取研究区在半个世纪以来的长时间序列冰流速度场；分析冰流速时空变化特征及其与冰架形态结构演变的相关性；建立基于数值模拟方法的冰流物理模型来研究冰架内部应力结构变化以及注出冰川对冰架变化的动态响应机制。项目预期成果将为研究南极冰川动态变化过程以及预测南极冰架稳定性提供重要的数据与理论支持。

南极冰盖的动态变化与物质平衡过程与全球气候变化以及海平面上升息息相关，冰架-冰川系统是南极冰盖的重要组成部分，流动速度是度量冰川动态变化以及物质平衡过程的重要参数。定量分析与模拟冰架-冰川的动态耦合机制对预测南极冰盖未来演化有着重要的意义。本项目基于多源遥感数据和影像匹配的特征追踪法提取了Getz冰架和拉森冰架长时间序列冰流速度场，分析了冰流速时空变化特征及其与冰架形态结构演变的相关性。进一步基于修正等高线法开展了南极伯德冰川高程误差校正及精度分析，基于多种卫星雷达测高数据开发了一系列湖泊水位估算的方法，提出了一种基于隐马尔可夫随机场的积雪时空建模技术和利用间灯光数据定量探测极区积雪的方法，为南极冰雪分析提供了重要的环境变量。利用多源遥感数据和冰盖-海平面系统模型探究了冰架前缘几何特征以及由冰裂隙引发的破坏对冰架动态变化过程的影响。项目成果将为研究南极冰川动态变化过程以及预测南极冰架稳定性提供重要的数据与理论支持。