基于多源数据的西北印度洋涡旋时空分布及大气响应

Spatial and Temporal Distribution of Eddies and Their Atmospheric Responses in the Northwest Indian Ocean Based on Multiple Datasets

【目的】基于多数据集研究西北印度洋涡旋的统计分布规律及其大气响应。【方法】通过高度计数据以及漂流浮标数据对西北印度洋从1993-2012年以来中尺度涡旋进行探测识别及统计分析。【结果】用高度计数据共探测到84551个中尺度涡旋,其中气旋涡44120个,反气旋涡40431个。其数量大概是海洋浮标探测到的涡旋数量的20倍,且涡旋大小、涡旋生命时长均比海洋漂流浮标探测到的要大。由高度计探测到的中尺度涡旋没有明显季节以及年度变化趋势,但由海洋漂流浮标探测到的中尺度以及次中尺度涡旋则表现出一定的季节性变化趋势。另外,通过比对探测到的涡旋与其上空大气场发现,反气旋涡上空对应正的风应力旋度异常,气旋涡上空对应负的风应力旋度异常。【结论】西北印度洋的次中尺度涡旋应该存在季节性变化趋势;反气旋涡使上空风速加快,而气旋涡则使上空风速减慢。

【Objective】To explore the statistical distribution and atmospheric responses of eddies in the northwest Indian Ocean through multiple datasets.【Method】Using altimeter data sets and ocean buoys,mesoscale eddies in the northwest Indian Ocean from 1993 to 2012 are detected,identified and statistically analyzed.【Result】Using altimeter data sets,a total of 84551 mesoscale eddies have been detected,including 44120 cyclonic eddies and 40431 anticyclonic eddies.the number of eddies detected from altimeter data is about 20 times that detected by ocean buoys.The size and lifetime of eddies detected from altimeter data are also larger than those detected by ocean buoys.The mesoscale eddies detected from altimeter data show no obvious annual or seasonal variation,while the mesoscale along with submesoscale eddies detected from ocean buoys show some seasonal variations.Moreover,by analyzing the interaction between the mesoscale eddies and the upper atmosphere,positive wind stress curl anomaly over the anticyclonic eddies and the corresponding negative wind stress curl anomaly over the cyclonic eddies are found.【Conclusion】To sum up,we deduce that submesoscale eddies in the northwest Indian Ocean have seasonal variations.And anticyclone eddies will speed up the wind above,while the cyclone eddies will slow down the wind above.