Investigating the GPM Dual‐frequency Precipitation Radar signatures of low‐level precipitation enhancement
Investigating the GPM Dual‐frequency Precipitation Radar signatures of low‐level precipitation enhancement
复制标题
DOI：
10.1002/qj.3611
复制
发表时间：
2019-08
影响因子：
8.9
通讯作者：
Leonardo Porcacchia;P. Kirstetter;V. Maggioni;S. Tanelli
中科院分区：
文献类型：
--
作者：
Leonardo Porcacchia;P. Kirstetter;V. Maggioni;S. Tanelli
高强度降水对世界上几个地区构成威胁，因为这与自然灾害（如洪水和山体滑坡）的风险有关。这项工作的重点是发生在云暖层中的低层降水增强，并已被观察到与碰撞合并（CC）有关，导致热带和温带地区的山洪暴发和极端降雨事件。具体而言，降水增强（称为CC主导降水）的信号是在2014年6月至2018年5月期间从美国中部/东部（CONUS）的全球降水测量（GPM）核心使命双频降水雷达（DPR）的观测中进行研究的。CC主导降水的分类方案，为双极化S波段雷达测量和应用在以前的工作中的X波段雷达观测在复杂的地形，被用作基准。该方案在这里应用于GPM地面验证数据集，该数据集将CONUS的地基雷达观测与星载DPR检索相匹配。记录了CC主导降水的发生，并研究了Ku和Ka波段CC主导降水的相应特征。与不受CC支配的剖面相比，CC主导剖面显示出显着的特征，例如，液体层中Ku和Ka波段反射率的特征垂直斜率，较低的冻结层高度和较浅的冰层，这些都与驱动特殊CC微物理的环境条件有关。这项工作的目的是改进卫星定量降水估计，特别是GPM检索，针对CC的发展，在降水列。
High‐intensity precipitation represents a threat for several regions of the world because of the related risk of natural disasters (e.g. floods and landslides). This work focuses on low‐level precipitation enhancement that occurs in the cloud warm layer and has been observed in relation to collision‐coalescence (CC) leading to flash floods and extreme rainfall events in tropical and temperate latitudes. Specifically, signatures of precipitation enhancement (referred to as CC‐dominant precipitation) are investigated in the observations from the Global Precipitation Measurement (GPM) core mission Dual‐frequency Precipitation Radar (DPR) over the central/eastern Contiguous United States (CONUS) during June 2014–May 2018. A classification scheme for CC‐dominant precipitation, developed for dual‐polarization S‐band radar measurements and applied in a previous work to X‐band radar observations in complex terrain, is used as a benchmark. The scheme is here applied to the GPM ground validation dataset that matches ground‐based radar observations across CONUS to space‐borne DPR retrievals. The occurrence of CC‐dominant precipitation is documented and the corresponding signatures of CC‐dominant precipitation at Ku‐ and Ka‐band are studied. CC‐dominant profiles show distinguishing features when compared to profiles not dominated by CC, e.g. characteristic vertical slopes of reflectivity at Ku‐ and Ka‐band in the liquid layer, lower freezing‐level height, and shallower ice layer, which are linked to environmental conditions driving the peculiar CC microphysics. This work aims at improving satellite quantitative precipitation estimation, particularly GPM retrievals, by targeting CC development in precipitation columns.