基于AMSR2高频亮温数据的南极海冰速度反演研究

南极海冰范围近年来突变减少，并在2017年达到有卫星观测以来的历史最低，南极海冰变化引起了国际关注。海冰运动是影响南极海冰变化的重要因素，但现有的全南极单源冰速遥感数据空间分辨率（不高于62.5 km）显著偏低，无法辨识精细的海冰运动。使用AMSR2高频波段（89 GHz）亮温可显著提升反演冰速的空间分辨率，但高频波段受大气噪声影响很大，仍缺少专门针对南极高频亮温的大气校正研究。为此，本研究将基于一个先进的辐射传输模型，发展一个考虑冰面发射率时空变化的大气校正方案，并研究高频亮温对大气廓线参数化方案的敏感性，确定合理的参数，以获取更加真实的南极冰面高频亮温初始场；改进南极冰速反演算法，并重构2012年至今、具有较高分辨率（约31.25 km）和精度的南极冰速数据，统计南极海冰运动特征并厘清其在近年突变减少中的作用。本项目将为南极研究提供重要的海冰运动数据，有助于提升对南极海冰变化的认识。

There is an abrupt decrease in the extent of Antarctic sea ice in recent years and reached its historical minimum in 2017 since satellite records. This makes the change in Antarctic sea ice a hot spot for researchers. Sea ice motion plays a key role in the change of Antarctic sea ice. However, the current Antarctic sea ice velocity data sets derived from satellites are unable to distinguish sea ice fine-scale dynamic processes due to their relatively low spatial resolution (no higher than 62.5 km). Using AMSR2 high-frequency brightness temperature data for ice velocity retrieval can improve the resolution of ice velocity effectively. However, the high-frequency brightness temperature is significantly affected by atmospheric noise, but there are few related studies on sea ice motion retrieval. Therefore, this project intends to develop an atmospheric correction method that regarding the spatial variability of sea ice emissivity. We will study the sensitivity of the high-frequency brightness temperature over the Antarctic sea ice surface to the cloud parameterization scheme in the radiative transfer model, and determine the reasonable parameters to obtain more accurate high-frequency brightness temperature; Further, we will develop a sea ice retrieval algorithm that is applicable on corrected high-frequency brightness temperature and acquire the daily sea ice velocity datasets in the Antarctic since 2012, which has a better spatial resolution (about 31.25 km) and higher accuracy. Finally, we will quantitatively investigate the contribution of sea ice motion on the retreat of sea ice extent in the past few years. This project will provide important basic sea ice motion data for Antarctic research and improve the understanding of Antarctic sea ice changes.