Characteristics of lightning and radar reflectivity in continental and oceanic thunderstorms

Radar data provide valuable information about storm development, track, and intensity, with the ability to provide indirect estimates of rainfall rates. However, radar data are not available or are very limited over most parts of the world, including oceans, mountains, and regions with sparse or no radar networks. Accurate, timely lightning data provide supplemental information about convective activity and can be used as a proxy for radar reflectivity. Moreover, data from global lightning detection networks can be used for rainfall estimation and data assimilation into NWP models over data-sparse regions.

In this study, lightning and radar data over the continental U.S. and adjacent ocean areas were collected and analyzed. The lightning data were obtained from Vaisala's National Lightning Detection Network (NLDN) and Global Lightning Dataset (GLD360) and the radar data from the National Weather Service NEXRAD. Preliminary results show a strong log-normal correlation between the lightning rates and reflectivity values. Other storm properties such as vertical reflectivity and temperature profiles were also investigated. Although the oceanic storms in this study were in the vicinity of land, some interesting differences were discovered between the storms over the land and ocean. Understanding the relationships among lightning, reflectivity, and rainfall rates will enable the development of enhanced radar proxy capabilities, as well as rainfall estimation techniques, particularly in regions where radar data are not readily available.