Land-Atmosphere interactions in the NARCCAP simulations: A process level approach to understanding model differences

Modeling and observational studies suggest that variations in the state of the land surface, including soil moisture and temperature, can have important implications for local weather and regional climate. This study examines differences in soil moisture memory and land-atmosphere coupling strength across an the ensemble of regional climate model (RCM) simulations produced as part of the North American Regional Climate Change Assessment Program (NARCCAP). The NARCCAP ensemble was produced by forcing 6 different RCMs with the current climate conditions (1971-200) and future climate conditions (2041-2070) from 4 different global climate models (GCMs). The climate response in temperature and precipitation over North America varies significantly across the different ensemble members as well as in the forcing GCMs. The goal of the work presented here is to examine the role that land-surface processes play in each ensemble member. Differences in each models representation of land-atmosphere coupling and soil moisture may provide a process level way to understand the disparate climate responses across the models. Land-atmosphere interactions are expected to play an important role in model difference over the Great Plains region of North America where land-surface moisture feedbacks are known to be large.