2002 Annual

Tuesday, 15 January 2002: 2:30 PM
Comparisons of cloud-to-ground lightning flash data with NEXRAD inferences on rainfall as functions of longitude and latitude
Thomas A. Seliga, Volpe National Transportation Systems Center, Cambridge, MA; and D. A. Hazen and C. Schauland
Poster PDF (449.9 kB)
Lightning flash data from the National Lightning Detection Network (NLDN) are used to examine the occurrence and transport of thunderstorms throughout the CONUS during the warm precipitation season of May through September of 1997. The analysis is compared with results of storm behavior from radar-based rainfall rates derived from a mosaic of NEXRAD data for the same period. Hovmoller diagrams of lightning cloud-to-ground flash rates are obtained for 15-minute time intervals and 0.2o latitude and longitude range intervals, spanning the same portion of the CONUS considered by other authors. The results of the comparison often show a high degree of correlation in time and space between flash density and NEXRAD-derived precipitation intensity. Occasions where the correlation is weak appear related to conditions when the precipitation events are non-convective. Thus, the inter-comparison of lightning and rainfall Hovmoller diagrams appears to provide an effective means of obtaining quantitative climatological measures of convection versus non-convection precipitation over the country. The results also appear highly relevant to aviation weather forecasting, since, similar to the NEXRAD rainfall results, the lightning activity often exhibits a high degree of coherency over extended time periods as thunderstorms transit longitudinally across the country. The diagrams appear useful as a new, valuable tool for assisting meteorologists in the forecasting and nowcasting of storms that impact enroute and terminal operations.

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