Winter clouds vertical structure of Yichang detected by millimeter-wave cloud radar

As an important part of the ground-based vertical observation systems, the millimeter-wave cloud radar (referred to as the cloud radar) can be used to observe cloud vertical structures and obtain cloud macro/micro-physical parameters. It is significant to analyze the detecting ability of the newly-built cloud radar for the data applications. In this study, the cloud radar observations at Three Gorges National Climatological Observatory from November 2022 to January 2023 are utilized. To reveal the vertical cloud structures in winter, the cloud base height (CBH), cloud top height (CTH), and radar reflectivity factor are compared with the measurements from the aerosol lidar observation instrument, FY-4A satellite, and the DSG5 precipitation phenomenon instrument, respectively. The results show that: (1) Under non-precipitation conditions, the cloud radar is well consistent with aerosol lidar observation instruments in detecting high and medium CBH, with correlation coefficients of 0.8 and 0.74, respectively. The correlation coefficient between the CTH detected by cloud radar and FY-4A is 0.57. Under weak-precipitation conditions, the reflectivity factor correlation coefficient between the cloud radar and precipitation phenomenon instrument is 0.66. (2) The occurrence frequency in winter shows a bimodal distribution in the Yichang region, with main peaks below 3 km. The cloud occurrence begins to increase in the afternoon, with the maximum values of non-precipitating clouds occurring in the evening (21:00—22:00) and the maximum values of precipitation clouds appearing at dusk (18:00—20:00). (3) Both the CBH and CTH exhibit bimodal distributions in the vertical distributions, with the main peak in the middle and lower layers of the troposphere. The elevation of the cloud base from evening to midnight indicates a decrease in precipitation. (4) The maximum radar reflectivity factor of non-precipitating clouds in winter is 20 dBz and mainly occurs in the afternoon. The maximum value of precipitating clouds exceeds 30 dBz and mainly occurs in the noon and dusk. Larger reflectivity factors in the low layers correspond to larger ground precipitation.