Comparison of Morphological and Physical Parameters of Rain Cells Observed by FY-3G PMR and GPM DPR in Boreal Summer

The Fengyun-3G (FY-3G) satellite, launched on 16 April 2023, carries China’s first spaceborne dual-frequency Precipitation Measurement Radar (PMR). This study aims to evaluate the precipitation detection capabilities of the PMR by comparing its observations of rain cells with those from a Dual-frequency Precipitation Radar (DPR) onboard the Global Precipitation Measurement (GPM) Core Observatory, thereby validating the performance of the new Chinese PMR against an internationally recognized standard. Using rain cell identification and minimum bounding rectangle fitting methods, we analyze the morphological and physical parameters of rain cells observed by both radars during the boreal summer (June–August) of 2024 over tropical (20°S–20°N), subtropical (20°–40°N), and mid-latitude (40°–52°N) regions. The results show good consistency between the two instruments in the distribution patterns of most geometric parameters, including length, width, horizontal shape index, and area. However, systematic differences are found in vertical structure and precipitation intensity: the PMR detects higher echo-top heights and a broader range of rain rates, particularly for convective precipitation, and exhibits larger standard deviations in both geometric and physical parameters due to its wider swath and potentially higher sensitivity. Geographically, both radars consistently reveal that tropical rain cells are predominantly convective, while mid-latitude rain cells are largely stratiform. Moreover, rain cells over land tend to be vertically elongated and horizontally narrow (lanky), whereas those over ocean are vertically compact and horizontally broad (squatty). The spatial distributions of the horizontal shape index and three-dimensional morphological index derived from the PMR and DPR show consistent geographical patterns, with a stronger linear correlation for the three-dimensional index. These findings demonstrate that the FY-3G PMR provides reliable and advanced precipitation observations comparable to the GPM DPR, confirming its capability to deliver high-quality data for global precipitation monitoring and research.