Impact of horizontal resolution on monsoon precipitation for CORDEX-South Asia: A regional earth system model assessment

For the first time for CORDEX-South Asia, a high-resolution regional earth system model (ROM) is adopted to assess impact of horizontal resolution (0.22° and 0.11°) in simulating Indian summer monsoon rainfall (ISMR) underlying spatiotemporal variability. ROM at both resolutions bears close resemblance observations mean precipitation climatology compared other climate models (RCMs) participated CORDEX- South Asia. shows substantial improvement relative ensemble RCMs included While comparing simulations with observations, some systematic wet dry bias over Central India (CI) Northern Western Ghats noticed. In general, wet/dry mainly associated overestimation/underestimation large-scale/convective component. Increasing from 0.22° 0.11° significantly adds value JJAS by reducing western central (WCI) southern peninsular eastern CI. The reduction suppression/enhancement large scale/convective precipitation. This partially due improved representation propagation mesoscale systems such as boreal intraseasonal oscillation (eastward northward). Despite above improvements, bias, particularly WCI, persists. weaker Findlater Jet land-ocean thermal contrast caused warm sea surface temperature (SST) Arabian Sea (AS) suggests that AS moisture transport does not contribute India. possibly favourable atmospheric conditions (atmospheric instability). • A namely implemented characteristics investigated. dynamical thermodynamical processes yield better simulation.