Evaluation of the atmosphere-land-ocean-sea ice interface processes in the Regional Arctic System Model Version 1 (RASM1) using local and globally gridded observations | CU Experts

Abstract. The Regional Arctic System Model version 1 (RASM1) has been developed to provide high-resolution simulations of the Arctic atmosphere-ocean-sea ice-land system. Here, we provide a baseline for the capability of RASM to simulate interface processes by comparing retrospective simulations from RASM1 for 1990–2014 with the Community Earth System Model version 1 (CESM1) and the spread across three recent reanalyses. Evaluations of surface and 2-m air temperature, surface radiative and turbulent fluxes, precipitation, and snow depth in the various models and reanalyses are performed using global and regional datasets and a variety of in situ datasets, including flux towers over land, ship cruises over oceans, and a field experiment over sea ice. These evaluations reveal that RASM1 simulates precipitation that is similar to CESM1, reanalyses, and satellite-gauge combined precipitation datasets over all river basins within the RASM domain. The possible reasons for this result are discussed. Snow depth in RASM is closer to upscaled surface observations over a flatter region than in more mountainous terrain in Alaska. The sea ice interface is well simulated in regards to radiation fluxes which generally fall within observational uncertainty. RASM1 surface temperature and radiation biases are shown to be due to biases in the simulated mean diurnal cycle. Development of RASM2 aims to address these biases.;

Brunke MA; Cassano JJ; Dawson N; DuVivier AK; Gutowski Jr. WJ; Hamman J; Maslowski W; Nijssen B; Reeves Eyre JEJ; Renteria JC

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