Climate Change Studies Using Coupled Model: Land Surface Perspective

Community Climate System Model (CCSM3), a coupled model developed by National Center for Atmospheric Research (NCAR) containing atmosphere, ocean, sea-ice and land processes, simulation have been analysed for suitability in the Indian Monsoon region. A long control run of CCSM3 with constant forcing at every year has been done and the model climatology has been generated using 20 years of simulation. Atmospheric component of the model has been able to capture the large scale phenomena, however, regional monsoon variability not fully captured by the model simulation. A suitable modification in the flux coupler and the convective parameterization process in regional scale certainly improve the atmospheric part of the climate system. Another major component of the climate model is the representation of Land Surface Processes (LSP). A successful inclusion of LSP in climate model must address the issues related to the regional scale variation of the properties of LSP. A proper understanding of land surface processes is very crucial for climate simulations using numerical models. To understand the LSP-monsoon coupling, the offline Community Land Model (CLM), taken from CCSM3 land component, simulation forced with three hourly atmospheric boundary conditions have also been analyzed and compared with the CLM version of coupled CCSM mode. The distribution of surface heat flux in CCSM coupled mode shows some discrepancies compared to the offline CLM. Both the simulation results are compared with existing climatological features and assessment to improve CCSM3 for the regional climate change studies is made.