Improved simulation of the polar atmospheric boundary layer by accounting for aerodynamic roughness in the parameterisation of surface scalar exchange ...

• Main Author: Elvidge, Andrew
• Format: Conference Object
• Language: unknown
• Published: GFZ German Research Centre for Geosciences 2023
• Subjects: Sea ice
• Online Access: https://dx.doi.org/10.57757/iugg23-2272; https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018492

<!--!introduction!--> A new, simple parameterisation scheme for scalar (heat and moisture) exchange over sea ice and the marginal ice zone is tested in a numerical weather and climate prediction model. This new “ Blended A87 ” scheme accounts for the influence of aerodynamic roughness on the relationship between momentum and scalar exchange over consolidated sea ice, in line with long-standing theory and recent field observations, and in contrast to the crude schemes currently operational in most models. Using aircraft observations and Met Office Unified Model simulations of cold-air outbreak (CAO) conditions over aerodynamically rough sea ice, we demonstrate striking improvements in model performance when the Blended A87 scheme replaces the model’s operational treatment for surface scalar exchange, provided that the aerodynamic roughness over consolidated ice is appropriately prescribed. The mean biases in surface sensible heat flux, surface latent heat flux, near-surface air temperature and surface ... : The 28th IUGG General Assembly (IUGG2023) (Berlin 2023) ...