Intercomparisons on the Vertical Profiles of Cloud Microphysical Properties From CloudSat Retrievals Over the North China Plain

Vertical profiles of cloud microphysical properties importantly determine the lifetime and precipitation rate of clouds. The 94-GHz cloud profiling radar (CPR) onboard the CloudSat satellite can measure the vertical profile of radar reflectivity, from which the microphysical properties of cloud can be retrieved. The retrievals bear variations due to various assumptions and auxiliary products used. This study targets on the mid-latitude clouds in the northern hemisphere, and intercompares the CloudSat products describing the vertical profiles of cloud microphysics and evaluate the uncertainties for each retrieval algorithm, with further evaluation by aircraft in-situ observations over the North China Plain region during 2013-2017. For those retrieval products performing phase apportion, the ambient temperature-based linear apportioning on mixed-phase clouds can produce reasonable estimation on ice water content, apart from the heavily precipitating clouds. The retrieved liquid water content constrained by cloud optical depth well matched in-situ observations, however its effective size is overestimated (hereby underestimating the number concentration of water droplets) because of the influence of larger precipitating hydrometeors on size distribution. The CPR-only retrieval can well produce the effective diameter and number concentration of ice for deep convection clouds, but using additional lidar constraint underestimates the effective diameter due to the intense attenuation by thick clouds. The analysis here suggests the appropriate parameters from various products for different cloud types, and provides guidance for future development of retrieval algorithms on vertical profiles of cloud microphysical properties.Plain Language Summary Vertical profiles of cloud microphysical properties play an important role in the cloud lifetime and precipitation rate. The 94-GHz cloud profiling radar (CPR) onboard the CloudSat satellite can retrieve the vertical profile of cloud microphysical properties based on measured radar reflectivity. However, the retrievals bear variations due to different assumptions and auxiliary products used. By comparing various CloudSat products and aircraft in-situ measurements over the North China Plain, our results demonstrate that radar retrievals constrained by cloud optical depth can well produce liquid water content but overestimate its effective diameter. For the temperature-based linear apportioning products, the mixed-phase clouds can produce reasonable estimation on ice water content, apart from the heavily precipitating clouds. These indicate the appropriate cloud microphysical parameters under certain circumstances using different retrieval algorithms and measurement constraints should be specific for cloud types.

Automated summary

Vertical profiles of cloud microphysical properties are crucial for cloud lifetime and precipitation rate. CloudSat CPR can retrieve these properties by measuring radar reflectivity. This study compares CloudSat products and aircraft in-situ measurements over North China Plain, finding that temperature-based linear apportioning of mixed-phase clouds provides reasonable estimation of ice water content. The liquid water content retrieved from cloud optical depth matches in-situ observations well, but its effective size is overestimated. The appropriate parameters for different cloud types and retrieval algorithms should be considered.