Characteristics of one sprite-producing summer thunderstorm

Abstract

Twenty-nine sprites were observed during four years from 2007 to 2010 with one most sprite-productive storm on 1–2 August 2007 which produced 16 sprites. In this paper, the most sprite-productive storm is analyzed by using data from lightning detection network, Doppler radar, MTSAT (Multi-Function Transport Satellite) satellite, TRMM (Tropical Rainfall Measuring Mission), NCEP. The results show that most sprites appeared in groups and in shape of carrot. Most sprites occurred frequently when the cloud top brightness temperature is getting warm and radar reflectivity is becoming weak with characteristics of sharp decrease of negative CGs and slight increase of positive CGs. The parent cloud-to-ground lightning flashes (CGs) were positive and located in region with cloud top brightness temperature of −40 to −60°C and radar reflectivity of 15–35dBZ. The sprite-producing storm was fortunately scanned by TRMM during sprite time period. One orbit data could be used for PR (Precipitation Radar, 2A25) and two orbit data for TMI (TRMM Microwave Imager, 2A12 and 1B11). Results based on TRMM indicated that storm reflectivity with 30dBZ was at about 12km in the convective region and 4km in stratiform region. The precipitation ice mostly located in 6–8km with the largest value of 2.1g/m3, but most cloud ice located between 10 and 14km with no cloud ice below 6km and very few at 6.0–8.0km. The cloud water content located mostly between 4 and 6km. Characteristics of vertical cross sections of radar reflectivity, precipitation ice and cloud ice agree well. Vertical cross sections along convective and stratiform regions show that contents of precipitation ice and cloud ice in convective region were larger than that in stratiform region. But cloud water in stratiform region was larger than that in convective region. The storm evolution could be seen clearly from characteristics of precipitation ice, cloud ice, cloud water and polarization corrected temperature at two different times. The CG distribution agrees well with low values of polarization corrected temperature region, indicating that lightning flashes have close relationship with ice particles. Although this paper is a case study of sprite-producing thunderstorm based on TRMM data, the results provided detailed information of microphysical structure of this sprite-producing storm.