Simulating the impact of the large-scale circulation on the 2-m temperature and precipitation climatology

摘要: The impact of the simulated large-scale atmospheric circulation on regional climate is examined using Weather Research and Forecasting (WRF) model as a model. purpose to understand potential need for interior grid nudging dynamical downscaling global (GCM) output air quality applications under changing climate. In this study we downscale NCEP-Department Energy Atmospheric Model Intercomparison Project (AMIP-II) Reanalysis three continuous 20-year WRF simulations: one simulation without two different methods. biases in 2-m temperature precipitation are unreasonably large with respect North American Regional (NARR) over eastern half contiguous United States (CONUS) during summer when concerns most relevant. This examines how these differences arise from errors predicting circulation. It demonstrated that Bermuda high, which strongly influences much CONUS summer, poorly nudging. particular, summers high was west (1993) east (2003) its climatological position chosen illustrate problems anomalies. For both summers, fails simulate placement upper-level anticyclonic cyclonic displacement impacts lower atmosphere moisture transport precipitable water, affecting convective environment precipitation. Using improves aloft transport/precipitable water anomalies, thereby improving results demonstrate constraining RCM features driving fields overall accuracy climate, suggest absence such constraint, will likely misrepresent important shifts future