南亚高压强度与邻近地区垂直速度的相互依赖关系

利用ERA-Interim 1979—2018年6—8月的再分析资料，通过相关分析、信息流、合成分析等方法研究了南亚高压强度与其邻近地区垂直速度的相互依赖关系.结果表明：南亚高压在上对流层-下平流层区域具有上冷下暖的热力结构，冷、暖中心分别在70 hPa和250 hPa，以这两层的温度异常建立的温差指数可以反映南亚高压的强度.在不同时间尺度上，南亚高压强度与其邻近地区垂直速度的相互依赖关系是不同的.在月时间尺度上，南亚高压强度通过动力作用影响邻近地区的垂直速度，南亚高压增强（减弱）时，其东部地区的上升运动和西部地区的下沉运动同步增强（减弱）；在日时间尺度上，南亚高压中部的垂直速度通过热力强迫影响南亚高压强度，南亚高压中部地区上升运动增强（减弱）时，南亚高压增强（减弱）且位置偏西（偏东）.

The interdependent relationship between the intensity of the South Asia High and the vertical velocity in its adjacent region

Using ERA-Interim reanalysis data in June, July and August (JJA) from 1979 to 2018, the interdependent relationship between the intensity of the South Asia High (SAH) and vertical velocity in its adjacent region was studied by correlation analysis, information flow and composite analysis. The results show that a thermal structure with upper cold anomaly and lower warm anomaly is located at upper troposphere-lower stratosphere (UTLS) region in the SAH. The cold and warm centers are situated at 70 hPa and 250 hPa respectively. The temperature difference index based on the temperature anomalies in these two layers can reflect the intensity of the SAH. The interdependent relationship between the intensity of the SAH and vertical velocity is variable on different time scale. On monthly time scale, the intensity of the SAH influences the vertical velocity in its adjacent areas through dynamic effect. When the SAH increases (decreases), the upwelling in the East and the subsidence in the West are strengthened (weakened) simultaneously. On daily time scale, the vertical velocity in the central region of the SAH affects the intensity of the SAH by thermal forcing. When the ascending motion in the central region of the SAH increases (decreases), the SAH is strengthened (weakened) and migrates westward (eastward).