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Original Paper Issue
On the Inconsistency of Cloud Liquid Water between Reanalyses and Satellite Observations over East Asia
Journal of Meteorological Research 2025, 39(4): 1025-1038
Published: 17 May 2025
Abstract Collect

Cloud water plays an important role in the global atmospheric water cycle and weather modification, but cloud is one of the most uncertain parameters in the study of weather and climate. The cloud water products from different data sources may have considerable discrepancies. In this study, the total cloud liquid water (termed as cloud liquid water path, LWP) obtained from satellite observations [Advanced Himawari Imager (AHI) and Advanced Microwave Scanning Radiometer (AMSR)] and three sets of modern reanalysis data (ERA5, JRA-55, and MERRA-2) are compared and analyzed. Moreover, characteristics of vertical distributions of cloud liquid water content (LWC) in different regions over East Asia are analyzed by using the profile data from the reanalyses. The main findings are as follows: (1) in extensive warm marine clouds, AHI and AMSR have a good agreement (with the correlation coefficient larger than 0.7) but with an overestimation from AHI; (2) under warm cloud conditions, the LWP in ERA5 shows a significant positive bias (about 0.065 kg m−2) over land, while MERRA-2 is closer to the satellite product compared with ERA5 and JRA-55; and (3) Southwest China (SW) is the area with most abundant LWC. The LWC is mainly concentrated in the middle and lower troposphere in the study area, and the LWC in ERA5 is higher than that in MERRA-2 and JRA-55. Overall, satellite observations and reanalyses exhibit significant inconsistency for cloud LWP, which needs further investigation and understanding.

Original Paper Issue
Analysis of a Hail Process in Foshan, Guangdong Province Using an Advanced Phased-Array Radar System and Development of a New Early Warning Index
Journal of Meteorological Research 2025, 39(1): 41-58
Published: 12 December 2024
Abstract Collect

Dual-Doppler radar detection and wind-field retrieval techniques are crucial for capturing small-scale structures within convective systems. The spatiotemporal resolution of radar data is a key factor influencing the accuracy of wind-field observations. Recently, an advanced X-band phased-array weather radar system was deployed in Foshan, Guangdong Province, China, comprising a central collaborative control unit and multiple networked phased-array radar front-ends. These radar front-ends work together to scan a common area, achieving a maximum data time difference of 5 s and a volume scan interval of 30 s, thereby providing three-dimensional wind-field data with higher spatiotemporal resolution and greater accuracy than achieved using traditional methods. This study utilized the X-band phased-array weather radar system to analyze the development of a substantial hailstorm that occurred over Foshan on 26 March 2022. Analysis indicated that hail cloud activity intensified considerably after 1442 local time, with the maximum reflectivity factor exceeding 60 dBZ above the altitude of the −20°C level, and reflectivity continued to increase over the subsequent 12 min. More precise information on the flow-field structure of the storm was obtained by examining the X-band radar data. The temporal and vertical variations in the maximum reflectivity factor, updraft velocity, vertical wind shear, and horizontal wind speed within a hailstorm cloud were scrutinized. The results show that the altitude, intensity, and range of the main updraft area increased as the storm core ascended. Concurrently, the vertical wind shear at mid‒lower levels of the storm became more pronounced as the altitude of the strong radar echo center increased prior to the peak of the updraft. Therefore, a new hail warning index was developed by using the vertical wind shear, and the index can be used to issue warnings up to 12 min earlier than achievable using traditional methods detecting increases in hailstorm intensity.

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