Evaluating surface variables simulated by NARCCAP over the Great Lakes Region and implications of climate change

The Great Lakes Region is an important resource for water usages and plays a significant role in the U.S. economy. This area might be susceptible to global warming. In response to the effect of the possible climate change, well-informed decisions depend on accurate regional assessments by climate models such as Global Circulation Models (GCMs) or Regional Climate Models (RCMs). We studied the reliability of the RCM simulation results from the North American Regional Climate Change Assessment Program (NARCCAP), by comparing historical runs with simulations from their host GCMs and gridded observations (truth data) from the Global Land Data Assimilation System (GLDAS). Surface variables such as surface air temperature, latent heat, sensible heat, soil moisture, and runoff were examined. The comparisons showed that, the RCMs exhibited better simulated primary surface features than GCMs partly because it can better represent lake and shoreline areas. The monthly climatology of latent heat and skin air temperature simulated by RCMs were close to the truth data, large biases were identified for sensible heat and runoff values. Projected changes of evapotranspiration and runoff for the mid-21st century over the Great Lake Region are mostly combined results of changed ratio of snow to total precipitation, different onset time of spring melting, and temperature change in summer.