南亚高压在高原建立的路径类型及其分析

Motion Tracks of South Asia High and Its Onset Mechanisms

利用1948—2006年NCEP/NCAR逐日再分析资料分析了南亚高压的移动路径、特征及其触发机制。根据高压的移动情况及其环流等特征发现,南亚高压的移动路径分为东路型,南路型和西路型。对比不同路径的温度场、风场及热源整层积分场等特征,发现不同路径之间存在很大差异。通过SVD分析以及合成分析发现,高原附近热源强弱配置的差异是造成路径差异的可能原因;同时,高原地区热力、动力作用造成的中低纬度的大气长波波型配置对路径的影响也至关重要。

Based on the NCEP/NCAR reanalysis data, the track-types of the South Asia high （SAH） during April to July, and its onset mechanisms over the Tibetan Plateau were investigated. The comparison of pentadly geopotential height and wind fields from April to July shows that the SAH had three types of tracks, i. e. east type（100-105°E）, south type（85-100°E）, and west type（60-85°E）, and moreover their corresponding heat source fields and wind fields were also different from each other. The SVD analysis of atmospheric heat source and 200 hPa geopotential height from April to July, and the composite analysis of wind and temperature fields over the first 15-day of May suggest that the distribution of heat source around the plateau might be related with the track type of SAH, and the pattern of long waves in the mid-low latitudes south of the plateau was also important in determing the track type of SAH.