| Summary: | Colorado State University, Walter Scott, Jr. College of Engineering, Department of Atmospheric Science We compare aspects of the present-day Arctic climate as simulated with the Community Earth System Model (CESM), and its super-parameterized counterpart (SP-CESM). Several observational and reanalysis datasets are used to evaluate important features of the simulated Arctic climates. We find that the present-day climate simulated with SP-CESM has more realistic surface air temperature, sea ice area and thickness, and sea level pressure compared to the conventional CESM. Observations from the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment show that in winter the Arctic exhibits two recurring and very different persistent regimes — one radiatively clear and the other opaquely cloudy. These two regimes affect the surface radiative fluxes and cloud particle phase. We analyze the radiative and microphysical properties of the simulated Arctic clouds and their influence on these regimes in CESM and SP-CESM. We find that SP-CESM is better able to simulate both of the observed regimes.
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