HEAVY RAINFALL STRUCTURES AND LIGHTNING ACTIVITIES IN A COLD-FRONT CYCLONEHAPPENED IN HUAI RIVER DERIVED FROM TRMM PR AND LIS OBSERVATIONS

Study has been made on heavy rainfall structures and lightning activities in clod-front cyclone occurred in Huai River reaches observed by TRMMPR and LIS separately in one and halfhour on June 22,2003 when raining season of the year started in the region.Precipitation profile features,lightning locations and its frequencies in this system were investigated and compared with those happened in a mesoscale convective system (MCS) near Wuhan city on July 20,1998.Results indicate that the enhancing process of cold-front cyclone system can be represented well by TBB observed by GOES,ratio of convective rainfall to stratiform rainfall,lightning locations and its occurring frequency.TRMMPR measurements show strong convective rainfall occurred along a narrow and long cold front,especially when the cyclone was deepening and the cold front was enhanced after one and halfhour.On the contrary,alarge area of stratiform rains occurred in a wide warm frontregion although there were several strong convectiverain blocks embedding in the wideregion.Comparing with the averaged convective profile that had the maximum rainfall rate in the lower at mosphere about 3 km~3.5 km in the MCS of 98.7.20,the maximum one in the cold-front cyclone system occurred near the ground surface,which may imply different microphysical processes inside precipitating clouds between the two systems.Results also indicate that many lightning activities can be detected in the narrow cold frontregion due to strong convective rains occur there.But almost no lightning activities happened in the wide warm frontregion although there was several strong convective rain blocks in the region.Furthermore,results show that the higher frequency of lightning occurrences at tends by a lot of icedroplets in the upper precipitating clouds from patterns of precipitation profiles.