南极普里兹湾固定冰的分布及生消过程研究

Landfast sea ice (fast ice) is stationary sea ice attached to coastal features such as the shoreline and grounded icebergs. It is a preeminent feature of the Antarctic coastal zone and an important interface between the ice sheet and pack ice/ocean. In recent years, the interannual variability in thickness, extent, morphology and persistence of the polar fast ice increased markedly, indicating that fast ice may be a sensitive indicator of climate change and is also closely associated with coastal polynyas. Coastal polynyas have far-reaching consequences in terms of Antarctic Bottom Water formation and hence global thermohaline circulation..In this study, we will present the first continuous, high spatiotemporal resolution time series of landfast sea ice extent in Prydz Bay, Antarctica. The time series was derived from satellite images of different visible/infrared, microwave sensors. To better understand the response and feedbacks of fast ice to large scale weather/ocean processes, spatial distribution and seasonal, annual, interannual variability of fast ice will be analyzed. Meanwhile, the role of fast ice in the formation of coastal polynyas adjacent to fast ice and glacier tongues will be investigated. Combined with the in situ observation and numerical models, the annual cycle and mass balance of fast ice and the driving role of large scale atmosphere/ocean processes will be explored.

固定冰是附着于沿岸特征如海岸线、冰架前沿或接地冰山并保持不动的海冰，它是南极沿岸的一个显著特征。固定冰范围的变动是气候变动的敏感指示器并与沿岸冰间湖密切相关，沿岸冰间湖对南极底层水AABW形成有着深远的影响，从而影响到全球热盐循环。.利用可见光/红外与微波波段卫星图像，本项目将构建南极普里兹湾高时空分辨率长时间序列连续的固定冰范围数据集，综合分析南极普里兹湾固定冰空间分布、季节、年、年际变动特征及其与南大洋海冰变动间的差异，深入研究固定冰范围变动对相邻冰间湖的影响及其对大尺度天气/海洋过程的响应与反馈机制。并结合观测数据与数值模拟，深入了解固定冰的生消与物质平衡变动过程，探寻大尺度天气和海洋过程对固定冰生消的驱动机理。

本项目依托中国南极科学考察与国际合作在戴维斯站附近固定冰上布放了一套海冰温度链浮标，获取了固定冰冰温剖面数据；收集了南极普里兹湾多套海冰物质平衡浮标与温度链浮标历史观测数据及相关气象观测资料，在此基础上分析了普里兹湾一年固定冰的季节变动特征；并结合一维海冰热力学模式HIGHTSI，探讨了太阳辐射通量、冰上积雪与冰下海洋热通量在固定冰生长与融化过程中的作用。评估了卫星遥感资料在构建海冰长时间观测记录上的可行性，改进了固定冰提取算法，生成了20年的连续的南极普里兹湾固定冰数据集，得到了普里兹湾固定冰空间分布及其季节与年际变动特征，并探讨大尺度环流模态对固定冰变动的影响。