资源环境科技发展态势分析平台

Multiplatform measurements of the active and passive instruments from A-Train were employed to observationally characterize particle structures over a spectrum of precipitating clouds from shallow cumulus to deep convection. Radar reflectivity profiles were composited as a function of temperature, with particle type superimposed to depict how storm regimes exert different particle habit structures. The deep convective system was found to have a relatively simple structure, which is dominated by randomly oriented ice, followed by snow and rain at the bottom, whereas the shallow cold system consisting high cloud tops with precipitation far below contains various hydrometeors, such as ice plates and drizzles. The deep convective system was further analyzed to demonstrate how the vertical microphysical structure tends to systematically transition from nonprecipitating to precipitating characteristics with differing cloud top buoyancies indicative of the "life stage" of convective development. The analysis offers a link between dynamical characteristics of convective systems and their inner hydrometeors structures.

Plain Language Summary Clouds are composed of liquid water droplets and condensed ice crystals or a mixture of both. Compared to liquid droplets, ice crystals are generally larger in size and, even with the same mass, allow more sunlight to reach the Earth's surface. Ice crystals also grow faster and end up falling as snow or melted rain, shortening the lifetime of a cloud. The phase states of these liquid and ice particles do not only persist over the lifetime of the cloud, but thermodynamic transitions between them often occur. Although these cloud-precipitation and thermodynamic phase processes occur in the vertical direction of the atmosphere, the vertical internal phase compositions of cloud-precipitation systems are still an open question in the atmospheric sciences, resulting in uncertainties in the surface temperature estimations in warmed atmospheres. In our study, we integrated independent measurements from space, analyzed various precipitating clouds from shallow to towering convective systems, and revealed variabilities in the vertical particle constituents among the precipitating cloud regimes. Studying the "static" measurement in a more "dynamical" context, we also show the observational insight of how the vertical structure of deep convective systems changes from "cloud mode" to "precipitation mode" during the course of their development.