A New Method for Retrieving Liquid and Ice Water Contents in 2023 Typhoon Khanun From FY-3G Precipitation Measurement Radar

FengYun-3G satellite was launched in April 2023, carrying onboard a precipitation measurement radar (PMR). In this study, FY-3G PMR data at Ku and Ka bands are assessed for retrieving cloud hydrometeor contents. A novel algorithm is developed to simultaneously retrieve the liquid and ice water contents (IWCs) and solid particle shapes at varying heights. For Typhoon Khanun, the hydrometeor content retrieved using this algorithm is close to the ERA5 rainwater and snow water at its developing and mature stages. The results show that the PMR minimum detectable reflectivity factor at Ku and Ka bands exceeds the design specifications, with values of 10 and 6 dBz, respectively. Furthermore, PMR signals primarily originate from the backscatter of larger particles, including rain, hail, and graupel. Using a prior relationship between the reflectivity and hydrometeor content at different temperatures, IWC and liquid water content (LWC) are retrieved and validated. It is found that Typhoon Khanun during the mature stage, compared to the development stage, IWC decreases while LWC increases. Moreover, based on Ku and Ka retrieval result, the most frequent shapes of typhoon solid particles are large column aggregate, Evans snow aggregate, gem graupel, and six-bullet rosette. Graupel particles are mainly concentrated in areas with high values of hydrometeor content. In some areas with high values of hydrometeors, large column aggregate is more prevalent, while Evans snow aggregate is mainly distributed in the areas with low values of hydrometeors.