Development of the Regional Arctic Climate System Model (RACM) --- Performance of the VIC land surface model in coupled simulations

Intensified warming of the Arctic region is expected to affect not only global climate but also to change the climate and hydrology of the continental land areas. Understanding the functioning of the Arctic climate system is important both because of its contribution to, and response from global change. To address these issues, a state-of- the-art Regional Arctic Climate system Model (RACM) is being constructed which includes high-resolution atmosphere, ocean, sea ice, and land hydrology components. As part of the RACM development, we have successfully coupled the macroscale Variable Infiltration Capacity (VIC) hydrology model with the Weather Research and Forecasting (WRF) regional climate model through the new Community Climate System Model (CCSM) flux coupling architecture CPL7. At present, the WRF/VIC coupled system has been run over the Arctic region in the wr50a grid for more than 3 months with ocean and sea ice conditions prescribed (“data model”) and is ready for long-time simulations. The ability of the WRF/VIC in RACM to reproduce hydrological processes is evaluated by comparing model simulations with gridded precipitation and temperature observations. We also compare surface runoff, snow water equivalent, latent heat, surface temperature and first layer soil temperature from WRF/VIC, WRF (Noah) and NCEP/NCAR reanalysis 2 data with observations for 2003. These efforts will later be expanded to form the foundation for evaluations of complex interactions and feedbacks among the components of the Arctic climate system, with particular focus on the land areas.