Evaluation of Atmospheric Boundary Layer Parameterizations to Estimate Energy and Mass Transport in the Arctic using the WRF Model

The Arctic is experiencing great environmental changes in response to atmospheric warming. Under changing and emerging climatic conditions, it is important to understand processes governing transport of energy and gases in the Arctic atmospheric boundary layer so as to reliably estimate these exchanges. Using numerical models, the transport of moisture, ozone, and other chemical species is computed using boundary layer parameterizations. Most of the commonly used boundary layer parameterizations have been developed for use in mid-latitude or tropical regions, where significantly different conditions predominate compared to the Arctic. Using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), we evaluate three widely used boundary layer schemes and compare their results to observations taken from CHACHA (CHemistry in the Arctic: Clouds, Halogens, And Aerosols) field campaign that took place in Utqiaġvik, Alaska during February to March 2022. We also implement and evaluate the performance of a new boundary layer parameterization based on prognostic equations for the heat flux and temperature variance. WRF-Chem outputs for vertical variations of wind speed, moisture, and ozone are contrasted with upper air sounding and aircraft measurements made over the tundra and the Beaufort Sea. Results show discrepancies among the different boundary layer parameterizations. The magnitude of discrepancies between model outputs and observations, and reasons for dissimilar results will be presented and discussed. In addition, recommendations on a modified atmospheric boundary layer parameterization for application to weakly and strongly stable conditions in the Arctic will be presented.