Present and future changes in precipitation characteristics during Indian summer monsoon in CORDEX‐CORE simulations

Abstract

This work examines the changes in precipitation characteristics over the Indian region using the latest high‐resolution CORDEX‐CORE model simulations. Individual RCM (COSMO, RegCM4.7, and REMO) experiments, their ensembles, and all RCM ensembles are examined to evaluate their performance using various statistical metrics. It aims to provide a holistic idea for choosing better models for specific analysis (variability, climatology, temporal evolution, indices, etc.) of precipitation distribution over India. The COSMO model experiments show lesser mean bias and have a high correlation coefficient (>0.8) compared to REMO and RegCM4. Each RCM ensemble performs better than its members in representing the spatial patterns of precipitation. Interestingly, the RCM experiments downscaling the forcings from MPI_ESM GCMs and ERA‐Interim outperforms other RCM experiments in the present day period. The probability distribution function reflects that the mean frequency and the intensity of precipitation are best represented in the RegCM4 ensemble. Further, most RCMs agree to a robust increase in low‐intensity rainfall (>0.1–4 mm⋅day ‑1 ) in the future under the RCP8.5 scenario. The intraseasonal variability in terms of active and break spells are best represented in the RegCM4 ensemble. There exists uncertainty in terms of projection of active phases, while all model experiments agree to the decrease in the break phases in the near future compared to the present day. The projected consecutive dry (wet) days and their spells will decrease (increase) over India. The heavy precipitation events are expected to increase (by 18–32 days) along with its contribution (by 14–48%) towards the total precipitation over entire India indicating a possible increase in flooding events in the future. The present‐day ISM characteristics is well captured in the model ensemble compared to individual experiments. The model ensemble indicates towards a robust increase in low‐intensity rainfall in the future. The very heavy precipitation events and its contribution towards total precipitation are increasing in the future.

Bibliographic Information