Characteristics of Global Light Rain System From GPM/DPR Measurements

Abstract Understanding the microphysical and macrophysical characteristics of global light rain (0.2–2.5 mm/hr) is important for modeling the hydrological cycle and enhancing the cloud‐related parameterization in the numerical weather prediction (NWP) model. To understand the characteristics of light rain systems, this study classified global light rain events using the Global Precipitation Measurement Dual‐frequency Precipitation Radar measurements over the 8–years period. As a result, global light rain systems were identified into four types based on microphysical (mass‐weighted mean diameter ( D m ) and normalized intercept parameter (log N w )) and macrophysical (cloud‐echo‐top height (CETH)) parameters. The four classified types are (a) Type 1: light rain dominant in tropics and mid‐latitude, (b) Type 2: light rain linked to atmospheric deep convection, (c) Type 3: light rain from humid oceanic inflow blocked by topography, and (d) Type 4: light rain associated with subtropical high‐pressure systems. Type 2 shows the largest D m and the smallest log N w , while Type 4 exhibited opposite patterns. Type 3 has the highest CETH and vertically stretching radar reflectivity profiles. Type 1 showed similar distributions of D m and log N w with Type 3 and radar reflectivity with Type 4 but different distributions of hydrometeor phase with Types 3 and 4. To clarify the characteristics of Type 1, a detailed analysis was conducted, showing larger D m and log N w , higher radar reflectivity, and stronger seasonality in tropical regions compared to mid‐latitudes. This study provides valuable insights into geospatial/statistical characteristics of global light rain, which is expected to enhance the accuracy of cloud parameterization in the NWP model.