On the relationships between lightning frequency and thundercloud parameters of regional precipitation systems

Abstract

Seasonal variations on lightning activity of precipitation systems over south China and Taiwan before and after the onset of Mei-Yu have been observed by the lightning imager sensor (LIS) on board the Tropical Rainfall Measuring Mission (TRMM) satellite. Lightning storms before Mei-Yu onset show higher probability of lightning, higher flash rate, and larger radar reflectivity in the mixed-phase region than the Mei-Yu regime. However, the probability of lightning occurrence with the same threshold of maximum radar reflectivity or ice scattering signature is similar for land systems before and during Mei-Yu season. Oceanic systems show slightly lower probability of lightning even with the same thresholds. Relationships between a set of TRMM-observed parameters and LIS lightning frequency are further examined. For lightning systems over land, the total area of radar echo above 35 dBZ has a closer relationship with lightning flash rate at the temperature between-5°C and-15°C than other parameters. Area of lower radar reflectivity at colder temperature, e.g., area of 20 dBZ at-40°C, is also highly correlated with lightning frequency. The highest correlation between area of specific radar reflectivity and lightning frequency is found at lower temperatures when the oceanic lightning systems are examined. Copyright 2010 by the American Geophysical Union.