Simulation of the atmospheric circulation in the Weddell Sea region using the limited-area model REMO

• Published in: Theoretical and Applied Climatology
• Main Author: Birnbaum, Gerit
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2003
• Subjects: Antarc*; Antarctic; Sea ice; Weddell Sea
• Online Access: https://epic.awi.de/id/eprint/4540/; https://doi.org/10.1007/s00704-002-0680-x; https://hdl.handle.net/10013/epic.15115

To analyse the applicability of a limited-area atmosphere model to theSouthern Ocean, a one-year simulation for 1985 is performed using the REgionalMOdel REMO at 55-km horizontal grid-spacing implemented for the Antarcticregions of the Weddell, Bellingshausen and Amundsen Seas. To evaluate theperformance of REMO, a comparison of model results to observations and toreanalysis/analysis data sets is carried out. REMO is initialized and driven atthe lateral and lower boundaries by data of the European Centre forMedium-Range Weather Forecasts (ECMWF) reanalysis (ERA15).Overall, REMO is an appropriate tool for further climate studies in Antarcticregions. It reproduces reasonably well basic spatial patterns and the seasonalcycle of the atmospheric circulation. However, the simulated mean sea levelpressure (MSLP) is predominantly lower than the MSLP provided by observationsand by ERA. Considerable temperature differences in the lower troposphere oversea ice in winter cause discrepancies between the REMO and ERA pressure fieldsin the mid-troposphere too. The precipitation rate P of the REMO simulationagrees qualitatively well with main features of the observed climatologicalspatial distribution described in literature. The seasonal cycle of P in theinner Weddell Sea reflects the Antarctic semi-annual oscillation. Concerningthe forcing fields, the ERA sea ice surface temperatures in winter aregenerally higher than satellite derived surface temperatures. Although thedifferences are 10 to 15 K in the southern Weddell Sea, this deficiency of theERA data hardly influences the mean large-scale circulation.