Climatology of precipitation and lightning over the Pacific coast of southern Mexico retrieved from Tropical Rainfall Measuring Mission satellite products and World Wide Lightning Location Network data

摘要

Tropical Rainfall Measuring Mission (TRMM) satellite products for the period 1998-2009 are used to elaborate the climatology of vertical hydrometeor profiles and diurnal evolution of rainfall over the Pacific coast of southern Mexico. Precipitation characteristics are compared with those of lightning strokes, registered by the World Wide Lightning Location Network (WWLLN). The WWLLN data are verified against a climatological product (High-Resolution Monthly Climatology, HRMC) obtained from merged data sets of the TRMM Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) of the MicroLab-1 satellite. The TRMM 2A12 data set reveals that summer precipitation over the study region is a result of mixed phase processes, whereas during winter and spring, there is a significant contribution of warm precipitation over land. Diurnal evolution of rainfall retrieved from the 3B42 TRMM product and lightning registered by the WWLLN follows the sea-land breeze cycle measured by Baumgardner et al. (2006; Evolution of anthropogenic aerosols in the coastal town of Salina Cruz, Mexico: part I particle dynamics and land-sea interactions, Science of the Total Environment, 367, pp. 288-301). The spatial distribution of lightning is similar to that of rainfall; however, over the seaside coastal region, a phase shift is observed between these two variables, with the maximum lightning activity occurring about 3 hours before the precipitation peak. Monthly distribution of flashes is monomodal over land and bimodal over the ocean. Over the ocean, the evolution of monthly rainfall during summer is contrary to that of lightning activity: the months with highest precipitation (June and September) correspond to those with the lowest number of lightning strokes, whereas during the mid-summer drought, an increase in electrical activity is observed. An explanation for this phenomenon, related to the wind circulation and its effect on the concentration of aerosol particles, is proposed.