Improved Simulation of Diurnal Cycle of Precipitation in the Maritime Continent Due to Rain Induced Surface Heat Flux

Precipitation can induce a surface sensible heat flux, as raindrops are generally cooler than the surface. This precipitation-induced sensible heat flux (Q_P), is often considered negligible and overlooked in models. However, during intense rainfall, Q_P can become significant and may not be negligible over regions such as the Maritime Continent, which receives tremendous amount of rainfall throughout the year. The Maritime Continent also exhibits a distinct diurnal cycle of precipitation that is primarily regulated by the land-sea temperature gradient. The land surface temperature is influenced by surface heat flux. Also, most high-resolution models generally have the diurnal cycle of precipitation peak that occurs too early and is too strong. We hypothesize that Q_P is non-negligible in the MC and by influencing other components of surface heat flux, it may improve the amplitude and phase of the diurnal precipitation peak. To test our conjecture, we conduct two simulations using a regional model during the passage of a Madden-Julian Oscillation (MJO) event in April 2009: Control (without Q_P) and SENS (with Q_P). Our findings highlight that during heavy rainfall events, maximum Q_P can surpass 100 W m^-2, which is comparable to other surface heat flux components. Moreover, the peak precipitation declines and come closer to the observation. The timing of peak precipitation is also improved by incorporating Q_P in the model. The mechanisms of such change in peak precipitation is discussed.