An examination of the relationship between lightning and rainfall over oceanic regions using the global lightning dataset (GLD360) and the tropical rainfall measuring mission precipitation radar (TRRM PR)

Abstract

Data from a precipitation radar (PR) on board NASA's Tropical Rainfall Measuring Mission (TRMM) satellite and data from Vaisala's network of groundbased, long-range lightning detection sensors (Global Lightning Dataset, GLD360) are used to examine the relationship between convective precipitation and lightning over the ocean. Data from May 2011 to February 2012 are analyzed across the North Atlantic Ocean, the Northeast Pacific Ocean, and the Northwest Pacific Ocean. The stroke density and maximum current of lightning strokes detected by GLD360 are compared to reflectivity observed by the TRMM PR. When the reflectivity is binned according to the stroke density and maximum current, the relationship between lightning and rainfall is found to be log-normal. Lightning occurring over each of the three ocean basins is associated with maximum reflectivity near 2 km altitude within a narrow range of values (45--50 dBZ). The reflectivity associated with stroke density and maximum current was shown to be 1--4 dBZ higher in winter than in summer. The maximum reflectivity above the freezing level is found to be larger for larger stroke density.