基于GPM/DPR数据的北疆地区降雪云宏观结构和微物理特征分析

Analysis of Macro Structure and Microphysical Characteristics of Snow Clouds in Northern Xinjiang Based on GPM/DPR Data

利用GPM/DPR双频降水雷达资料、FY-2E卫星资料和地面降水实况,对新疆北部四次成熟期降雪过程的红外亮温、水平分布和垂直结构特征进行了分析。结果表明:降雪云团的云顶亮温集中在210~245 K,降雪云主要为层状云,中云对降水率贡献最大,近地面降水率多分布于0.5~2.0 mm·h^(-1),回波顶高主要集中在3.0~4.5 km范围内,回波顶高与近地表降水率强弱变化存在正相关;雷达反射率因子(Z)范围在22~35 dBz,强回波中心高度主要分布在1.25~4.50 km;质量加权平均直径(D_(m))为1.01~1.25 mm和粒子数浓度(dB N_(w))为32~36的配置贡献的降水最多,对应的高度范围为2.19~2.50 km和2.13~2.67 km;近地表由碰撞-聚并过程产生的大粒子较多,近地表附近D_(m)达到了2.33~3.00 mm,Z和D_(m)朝地面几乎恒定或稍有增加,Z和D_(m)数值大小与地表降水量变化呈正相关特征。

Based on GPM/DPR dual-frequency precipitation radar,FY-2E satellite and surface precipitation data,the infrared brightness temperature,horizontal distribution and vertical structure characteristics of the four snowfall processes during mature period in northern Xinjiang are analyzed.The results show that the cloud top brightness temperature of the snowfall is concentrated at 210-245 K,and the snowfall clouds are mainly stratiform clouds.The middle clouds contribute the most to the precipitation intensity,and the near-surface precipitation rate is mostly distributed between 0.5-2.0 mm·h^(-1).The echo top height in areas with high precipitation rate is mainly concentrated in the range of 3.0-4.5 km,and there is a positive correlation between the echo top height and the variation of near-surface precipitation rate.The range of radar reflectivity factor(Z)is between 22-35 dBz,and the height of the strong echo center is mainly distributed in 1.25-4.50 km.The configuration with mass weighted average diameter(D_(m))of 1.01-1.25 mm and particle number concentration(dB N_(w))of 32-36 contributes the most precipitation,and the corresponding heights are 2.19-2.50 km and 2.13-2.67 km.Near the surface,there are more large particles produced by the collision-convergence process,and the D_(m) reaches 2.33-3.00 mm near surface.Toward the surface,Z and D m are almost constant or slightly increase,and the values of Z and D_(m) are positively correlated to the variation of surface rainfall.