The lightning Imaging Sensor (LIS) on TRMM can detect the distribution and variability of total lightning (cloud-to-cloud and cloud-to-ground lightning) that occurs in the tropical regions of the globe. The lightning storms can be defined by counting the total number of observed flashes within the precipitation systems.
There are two ways to rank these lightning storms. One is to use the total number of flashes within a precipitation system from TRMM snapshots, which is our current method. This method is likely to give a high rank to a system with large size. For example, a MCS with several convective cells connected by stratiform raining regions with little lightning activity may have more flashes than a stand alone supercell, though the supercell may have much higher flash rates per unit area. Another way is to use the flash rate defined by dividing the total number of flashes with view time of the precipitation system by TRMM. In the future, we would implement the second method as well.
Thunderstorms over different regions
Apparently, lightning storms over Central Africa have much more flashes than the rare lightning events over tropical oceans. So it is important to separate lightning events for different regions. Currently our plan is to show the top 10 (or more) thunderstorms for each 10x10 degree box globally. The result will come out soon...
Thunderstorms in different seasons
Currently the plan is to show the top 10 (or more) lightning storm cases for each 10x10 degree box globally for four different seasons (DJF, MAM, JJA, SON). The result will come out soon...