New study suggests large organised storms cause rainfall increase

A new study, partly based on satellite data, finds the cause of increasing rainfall in the wettest regions of the tropics: more frequent large and well-organised thunderstorms.

The Australian Research Council Centre of Excellence for Climate System Science (ARCCSS) and NASA have developed a joint research project whose results are published online in "Nature". It reveals that rainfall increases seen in places such as the western Pacific in recent decades are due to large storms happening more frequently.

"The observations showed the increase in rainfall is directly caused by the change in the character of rain events in the tropics rather than a change in the total number of rain events. What we are seeing is more big and organized storms and fewer small and disorganized rain events," said lead author Jackson Tan.

The researchers analysed rainfall data from NASA’s Tropical Rainfall Measuring Mission (from 1998-2009) and from the Global Precipitation Climatology Project (from 1983-2009). These rainfall data were compared to cloud data from the International Satellite Cloud Climatology Project for the period from 1983 to 2009, as NASA informed.