Dynamical Downscaling Approach for Wintertime Seasonal-Scale Simulation over the Western Himalayas

The performance of RegCM4 for seasonal-scale simulation of winter
circulation and associated precipitation over the Western Himalayas
(WH) is examined. The model simulates the circulation features and precipitation
in three distinct precipitation years reasonably well. It is found
that the RMSE decreases and correlation coefficient increases in the precipitation
simulations with the increase of model horizontal resolutions.
The ETS and POD for the simulated precipitation also indicate that the
performance of model is better at 30 km resolution than at 60 and 90 km
resolutions. This improvement comes due to better representation of orography
in the high-resolution model in which sharp orography gradient in
the domain plays an important role in wintertime precipitation processes.
A comparison of model-simulated precipitation with observed precipitation
at 17 station locations has been carried out. Overall, the results suggest
that 30 km model produced better skill in simulating the precipitation
over the WH and this model is a useful tool for further regional
downscaling studies.