南大洋太平洋扇区中尺度涡旋的统计特性及其变化

中尺度涡旋在南大洋海洋动力学中具有重要地位，其对气候变化的响应表现也引起了海洋学家与气候学家的广泛关注。本文利用涡动动能与涡旋自动探测技术两种方法对南大洋太平洋扇区的涡旋特性及其变化进行了分析。与前人结果相一致的是，高值的涡动动能主要集中在南极极锋海区，并且自西向东逐渐减弱。在过去的20年里，涡动动能在太平洋扇区的显著增强也集中在中西部海域，这里也是南极绕极流斜压性较强的海域。涡旋统计特性揭示了涡动动能的空间分布及其年际变化主要归因于涡旋振幅与旋转速度，而并非涡旋个数或者涡旋半径。这些结果进一步确认了对应于南半球环状模正位相的绕极西风异常改变了南大洋的涡旋特性，从而表现出涡旋活跃性增强。

Eddy properties in the Pacific sector of the Southern Ocean from satellite altimetry data

Mesoscale eddies play a key role in the ocean dynamics of the Southern Ocean, and eddy response to the climate changes has also been widely noted. Both eddy kinetic energy (EKE) and eddy detection algorithm are used to study the eddy properties in the Pacific sector of the Southern Ocean. Consistent with previous works, the maps of the EKE illustrate that higher energy confines to the Antarctic Polar Frontal Zone (APFZ) and decreases progressively from west to east. It also shows that the most significant increase in the EKE occurs in the western and central parts of the Pacific sector, where the baroclinicity of the Antarctic Circumpolar Current (ACC) is much stronger. Statistical eddy properties reveal that both of the spatial pattern and interannual variation of the EKE are primarily due to the eddy amplitude and the eddy rotational speed, rather than the eddy number or the eddy radius. In general, these results furtherly confirm that anomalous westerly wind forcing associated with the positive Southern Annular Mode (SAM) index enhances the Southern Ocean eddy activity by strengthening the eddy properties.