Fig. 6: Diurnal cycle of precipitation over the sea and land.

Mean diurnal cycle of the precipitation rate (mm hr⁻¹) from observations and simulations, averaged over (a) sea and (b) land. The green solid line represents TRMM precipitation. The orange, blue, black, and red solid lines indicate precipitation from the very-low-aerosol, low-aerosol, control, and high-aerosol runs, respectively, while the dashed lines represent precipitation from the low-aerosol-norad (blue), control-norad (black), and high-aerosol-norad (red) runs. ‘norad’ denotes simulations in which direct aerosol radiative effects are excluded. The abscissa denotes local standard time (LST), corresponding to UTC + 8 h. Mean diurnal cycle of the TRMM precipitation rate (mm hr⁻¹;) for different levels of MERRA-2 AOD over (c) sea and (d) land during October to January in the ENSO-neutral years 2001, 2003, 2012, and 2013. The diurnal cycles for high- and low-AOD conditions (corresponding to upper 5% and lower 5% AOD days, respectively) are represented by red and blue lines, respectively. Among the high-AOD cases, two different subsets with peaks at ~17:00 LST and ~23:00 LST are also shown as dotted and solid orange lines. Their respective AOD means are nearly the same, with the former comprising two-thirds of the population and the latter one-third. Notably, for high-AOD cases, the 23:00 LST peak coexists with the conventional 17:00 LST peak.