Projection of lightning over South/South East Asia using CMIP5 models

Product of Bowen ratio with the sum of precipitation rate and evaporation rate has been used as proxy to evaluate the seasonal and annual spatial distributions of lightning flash rate over South/Southeast Asian region (60-120 degrees E, 0-40 degrees N) with 9 models from the Coupled Model Inter-comparison Project-Phase 5 (CMIP5). The model-simulated mean LFR with each model is positively correlated with the satellite-observed LFR on both seasonal and annual scales. The satellite-observed LFR is correlated with the ensemble mean LFR of the models with a correlation coefficient of 0.93 over the region. The model-simulated LFR has also been used for projection of lightning in the late twenty-first century. Overall, the projected LFR over whole study area shows a 6.75% increase during the (2079-2088) period in high radiative forcing scenario (RCP8.5) as compared to the historic period of (1996-2005). Rise in LFR is also identified using another projected period (2051-2060) and a lower radiative forcing scenario condition (RCP4.5), though lesser in magnitude, as expected. For the projected period (2051-60) in the RCP8.5 case, LFR over the domain shows an increase of 4.3%; whereas for a lower future scenario condition (RCP4.5), it indicates a rise by 5.36% at the end of the twenty-first century. Moreover, results indicate an increase in extreme events of severe convective storms with intense lightning in mountainous dry regions at the end of the twenty-first century. It is suggested that the proxy used here is favourable for projection of LFR in this region and perhaps for the whole tropical area.