Properties and Occurrence of Shallow Isolated Warm Rain Events over the Tropical Ocean as Observed by GPM DPR

Shallow isolated warm rain events are prevalent over the tropical ocean. Location, environmental conditions, and timing may influence the development of these rain events, producing multiple distinct types of rain events with different structure, properties, and impacts. It is important to study the structure and properties of shallow warm rain events as well as quantify any differences in these that may occur so that the effects of such events on the surrounding environment may be correctly represented in models and climatologies of the region. The Global Precipitation Measurement (GPM) mission's core satellite Dual frequency Precipitation Radar (DPR) observes two distinct groups of shallow isolated warm rain based on their near surface radar reflectivity and echo top height. The first has relatively strong (> 20 dBZ) maximum near surface reflectivities, and a wide range in echo top heights, while the second has weaker (< 20 dBZ) maximum near surface reflectivities and a narrower range in echo top heights with a tendency for these to be slightly higher (> 2.25 km). We utilize a database of contiguous DPR raining pixels grouped into precipitation features (PFs), as well as DPR pixel level data and collocated ERA-Interim variables such as 2 m dew point, wind speed, and total column water vapor, in order to determine whether these two groups indeed represent distinct types of shallow isolated warm rain and if so, quantify their structure, occurrence, and the differences in environmental conditions leading to their formation.