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

Abstract

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. Snow depth in RASM is closer to upscaled surface observations over a flatter region than in more mountainous terrain in Alaska. The sea ice–atmosphere interface is well simulated in regards to radiation fluxes, which generally fall within observational uncertainty. RASM1 monthly mean surface temperature and radiation biases are shown to be due to biases in the simulated mean diurnal cycle. At some locations, a minimal monthly mean bias is shown to be due to the compensation of roughly equal but opposite biases between daytime and nighttime, whereas this is not the case at locations where the monthly mean bias is higher in magnitude. These biases are derived from errors in the diurnal cycle of the energy balance (radiative and turbulent flux) components. Therefore, the key to advancing the simulation of SAT and the surface energy budget would be to improve the representation of the diurnal cycle of radiative and turbulent fluxes. The development of RASM2 aims to address these biases. Still, an advantage of RASM1 is that it captures the interannual and interdecadal variability in the climate of the Arctic region, which global models like CESM cannot do.

Hidden Production: On the Importance of Pelagic Phytoplankton Blooms Beneath Arctic Sea Ice

“…The model resolution is 50 km for WRF and VIC, and 1/12°(9 km) for POP, CICE, and mBGC. RASM has been developed over the past decade, and each component, as well as the fully coupled system, has been evaluated substantially (Brunke et al, 2018;Cassano et al, 2017;DuVivier et al, 2016;Hamman et al, 2016Hamman et al, , 2017Jin et al, 2018;A. Roberts et al, 2015;A.…”

“…The model resolution is 50 km for WRF and VIC, and 1/12° (9 km) for POP, CICE, and mBGC. RASM has been developed over the past decade, and each component, as well as the fully coupled system, has been evaluated substantially (Brunke et al, 2018; Cassano et al, 2017; DuVivier et al, 2016; Hamman et al, 2016, 2017; Jin et al, 2018; A. Roberts et al, 2015; A. F. Roberts et al, 2018). The most recent components added to this system model are ocean and sea ice biogeochemistry (mBGC), which were added in 2013 and 2016, respectively (Jeffery et al, 2020; Jin et al, 2018).…”

Investigation of Under‐Ice Phytoplankton Growth in the Fully‐Coupled, High‐Resolution Regional Arctic System Model

“…The model resolution is 50 km for WRF and VIC, and 1/12° (approximately 9 km) for POP and CICE. RASM has been demonstrated to correspond well with observations in its representation of the upper‐ocean physical dynamics (DuVivier et al., 2016; Hamman et al., 2017; Roberts et al., 2015), arctic climate (Cassano et al., 2017; Hamman et al., 2017) and processes across the coupled atmosphere–land–ocean–sea ice interface (Brunke et al., 2018).…”

On the circulation, water mass distribution, and nutrient concentrations of the western Chukchi Sea

“…We utilize results from the Regional Arctic System Model (RASM) to assess the circulation and water mass characteristics in the Chukchi Sea. RASM has been developed over the past decade and each component, as well as the fully-coupled system, has been thoroughly evaluated (Brunke et al, 2018;Cassano et al, 2017;Clement Kinney et al, 2020;DuVivier et al, 2016;Hamman et al, 2016Hamman et al, , 2017Jin et al, 2018;Roberts et al, 2015;Roberts et al, 2018). RASM is a high-resolution atmosphereice-ocean-land regional model with a domain encompassing the entire marine cryosphere of the Northern Hemisphere, including the major inflow and outflow pathways, with extensions into the North Pacific and Atlantic oceans.…”