基于GPM双频雷达探测的冬季北半球风暴路径降水特征研究

The northern hemispheric storm tracks occurred in the mid-latitude region of the Pacific and Atlantic. It impacts the global climate through the widespread and systematical transportation of moisture and heat, and angular momentum, and its change also associates with increased extreme cold winter events in recent years. Our survey has shown that many achievements on the studies of storm tracks have been obtained in synoptics, dynamics and climatology. However, the knowledge of precipitation in storm tracks is still limited due to the shortage of effective measurements. In the proposed studies, the characteristics of precipitation and its latent heating in the northern hemispheric storm tracks will be investigated based on measurements of the GPM (Global Precipitation Mission) DPR (Dual-frequency Precipitation Radar) and GMI (GPM Microwave Imager) onboard the satellite that has been successfully launched on Feb. 28, 2014, combining with the reanalysis data. The purposes of the proposal are as following. Firstly, the distribution of rainfall intensity and frequency etc. for precipitation in different properties (rain, snow, or both mixed) and types (convective, stratiform, or others) in storm tracks will be exposed. Secondly, the vertical structures of precipitation and their latent heating structures for these different properties and types will be illustrated. Thirdly, the statistical corresponding relation between the atmospheric parameters and precipitation in vertically inside cyclones will be revealed by creating the three-dimensional structures constituted by precipitation structures, microwave signals and atmospheric parameters. The realization of our proposal will promote our knowledge on precipitation in storm tracks.

北半球风暴路径（也称为风暴轴）发生在中纬度太平洋和大西洋地区，它通过大范围和系统性的水汽、热量及角动量输送来影响全球气候，其变化还与近年来冬季极端寒冷事件增多有关；风暴路径的天气学、动力学及其气候变化的研究已经取得了丰富的成果。然而，因缺乏有效的探测技术手段，我们对北半球风暴路径上的降水特征还缺乏认知。本项目将利用2014年2月28日升空的全球降水测量（GPM）卫星上搭载的双频测雨雷达（DPR）和微波成像仪（GMI）的探测结果，结合再分析资料，研究北半球风暴路径上降水及潜热特征，揭示风暴路径上不同性质（降雨、降雪、混合降水）和不同类型（对流降水、层云降水等）降水的强度和频次等分布特征，揭示它们的垂直结构及相应潜热结构特征，揭示风暴路径上气旋内大气参数垂直结构与降水垂直结构的对应关系，建立包含降水结构、微波信号和大气参数的气旋三维结构物理图像。上述研究将提升我们对风暴路径上降水的物理学认知。

本项目通过利用GPM卫星上搭载的DPR和GMI的探测结果，结合最新的再分析大气参数数据，研究了北半球风暴路径上的降水特征，率先揭示了风暴路径气旋中心区降水的空间分布特征和大气参数分布特征；发现风暴路径大气扰动中心区与降水中心区错位现象；初步揭示了风暴路径气旋引发降水空间位置特点，即降水落区多位于气旋的暖区和大气斜压性最大区域，而不是位于大气扰动中心（低压中心）；初步给出了风暴路径气旋潜热垂直结构。项目还研发了一种卫星云降水参数与模式再分析大气参数进行融合的技术方法，并在申请专利中。上述研究结果提升我们对风暴路径上云和降水的物理学认识。