大气扰动分解技术在副高边缘大暴雨落区精细化分析中的应用

利用欧洲中期天气预报中心（European Centre for Medium-Range Weather Forecasts, ECMWF）再分析资料,基于大气扰动分解技术,对2012年7月华北东部两次副高边缘大暴雨事件进行扰动分析。结果表明：边界层及对流层低层扰动辐合中心与副高边缘大暴雨中心有较好地对应关系;扰动锋区和扰动比湿大值区（4 g·kg^-1）叠加的区域与大暴雨落区相对应,与切变线类暴雨不同,副高边缘暴雨中心并不是出现在冷暖空气対峙扰动（0 ℃线）的位置,而是发生在扰动锋区内的暖区一侧（扰动温度0 ℃以南）;两次过程均存在自南向北的水汽通道,且水汽在输送过程中不断得到抬升,大暴雨落区对应的扰动水汽通量散度中心分别达到-6.8×10^-8g·cm^-2·hPa^-1·s^-1和-11.9×10^-8g·cm^-2·hPa^-1·s^-1,为大暴雨的形成提供了较好地水汽条件。

The application of atmospheric disturbance decomposition technology in the detailed analysis of the heavy rainstorm area at the edge of subtropical high

Based on atmospheric disturbance decomposition technology, ECMWF reanalysis data was used to analyze two heavy rain events on the edge of subtropical high in eastern North China in July 2012. Results show that there is a good correspondence between the anomalous convergence center at the boundary layer or in the lower troposphere and the center of heavy rain on the northwest edge of the subtropical high. The superimposed area between the anomalous front area and the larger anomalous specific humidity (4 g·kg^-1) area corresponds to the rainstorm area. Unlike the rainstorm caused by shear line, the rainstorm center on the edge of the subtropical high does not appear in the position between cold and warm air, where the anomalous temperature is zero, but in the warm side of the anomalous front area(to the south of anomalous temperature zero line). Vapor transported from south to North, and water vapor in the transport process has been continuously lifted. The convergence center of anomalous water vapor flux corresponding to the heavy rain area reaches -6.8×10^-8g·cm^-2·hPa^-1·s^-1 and -11.9×10^-8g·cm^-2·hPa^-1·s^-1, respectively,which provides a favorable condition of water vapor accumulation for the formation of heavy rain.