华北地区“7·20”强降水过程扰动能量时空分布特征研究

Temporal and Spatial Distribution Characteristics of Disturbance Energy in “7·20” Precipitation Process in North China

摘要: 本文利用国家气候中心台站降水数据及欧洲中期天气预报中心(ECMWF)再分析格点资料，使用Morlet小波分析、巴特沃斯带通滤波及波包传播诊断方法主要对华北地区“7·20”强降水过程进行扰动能量的分析。结果表明风场扰动能量时空分布特征基本上可以对应华北地区“7·20”强降水过程的发展特征。强降水期间纬向、经向风场的扰动能量不仅代表冷暖空气和水汽的输送，也一定程度上反映了不稳定能量(动能)的输送，经向风场的扰动能量分布与动能的分布有很好的对应关系。强降水落区基本上为风场扰动能量高值区，降水落区主要沿强扰动能量等值线形状分布并沿等值线的分布形状移动，经向风场及纬向风场的扰动能量分布等值线走向可以反映水汽、冷暖空气的输送强弱，风场的扰动能量积累频散特征基本可以代表强降水期间能量的积累释放过程。

Abstract: In this paper, we use the precipitation data of the National Climate Center Station and the reanalysis data from the ECMWF. Morlet wavelet analysis, Butterworth bandpass filter and Wave packet propagation diagnosis method are used to analyze the disturbance energy of the “7·20” precipitation in North China. The results show that the temporal and spatial distribution of wind disturbance energy can basically correspond to the development characteristics of the “7·20” heavy precipitation process in North China. During heavy rainfall, the perturbation energy of zonal and meridional winds not only represents the transport of cold and warm air and water vapor, but also reflects the transport of unstable energy (kinetic energy). The distribution of perturbation energy of meridional wind field has a good corresponding relationship with the distribution of kinetic energy. The strong precipitation fall area is basically the high value area of disturbance energy of the wind field. The precipitation fall area mainly distributes along the contour of the strong disturbance energy contour and moves along the distribution shape of the isoline, and the perturbation energy of the meridional wind field and the zonal wind field. The trend of distribution contours can reflect the strength of water vapor and cold and warm air. The characteristics of dispersion energy accumulation in the wind field can basically represent the process of energy accumulation and release during periods of heavy rainfall.