Understanding the drivers of near-surface winds in Adelie land, East Antarctica
Near-surface winds play a crucial role in the climate of Antarctica, but accurately quantifying and understanding their drivers is complex. They result from the contribution of two distinct families of drivers: large-scale pressure gradient, and surface-induced pressure gradients known as katabatic...
| Main Authors: | , , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Copernicus Publications
2023
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| Subjects: | |
| Online Access: | https://doi.org/10.5194/egusphere-2023-2045 https://noa.gwlb.de/receive/cop_mods_00069077 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00067479/egusphere-2023-2045.pdf https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2045/egusphere-2023-2045.pdf |
| Summary: | Near-surface winds play a crucial role in the climate of Antarctica, but accurately quantifying and understanding their drivers is complex. They result from the contribution of two distinct families of drivers: large-scale pressure gradient, and surface-induced pressure gradients known as katabatic and thermal wind. The extrapolation of vertical potential temperature above the boundary layer down to the surface enables us to separate and quantify the contribution of these different pressure gradients in the momentum budget equations. Using this method applied to outputs of the regional atmospheric model MAR at a 3-hourly resolution, we find that the seasonal and spatial variability of near-surface winds in Adélie Land is dominated by surface processes. On the other hand, high temporal variability (3-hourly) is mainly controlled by large-scale variability everywhere in Antarctica, except in the coastal area. In these coastal regions, although the katabatic acceleration surpasses all other accelerations in magnitude, none of the katabatic nor large-scale accelerations can be identified as primary drivers of near-surface winds variability. Strong wind speed events in coastal Antarctica are driven by both katabatic and large-scale accelerations, as well as the angle between them. |
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