PNNL

Abstract

In this study, the regional WRF-Chem model is updated for improved simulations of short-lived pollutants (aerosols, ozone) in the Arctic. Specifically, we include in WRF-Chem 3.5.1 (SAPRC-99 gas phase chemistry, MOSAIC aerosols) (1) a correction to the sedimentation of aerosols, (2) dimethylsulfide (DMS) oceanic emissions and chemistry, (3) an improved representation of the dry deposition of trace gases over seasonal snow, (4) a dependence on snow and ice cover of UV-albedo for photolysis calculations. We also (5) correct the representation of surface temperatures over melting ice in the Noah Land Surface Model and (6) couple and test further the recent KF-CuP (Kain-Fritsch + Cumulus Potential) cumulus parameterization including aerosol-cumulus-chemistry interactions in WRF-Chem. The updated version of the model is used to perform simulations of aerosols and ozone at the quasi-hemispheric scale, which are evaluated against surface black carbon (BC), surface ozone and surface sulfate measurements in the Arctic, and airborne BC measurements. This evaluation shows significant improvements in terms of seasonal aerosol cycles at the surface, root mean square errors (RMSE) for surface ozone and aerosols,