Impact of swell on simulations using a regional atmospheric climate model
2009 (English)In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 61, no 4, 527-538 p.Article in journal (Refereed) Published
When long, fast swell waves travel in approximately the same direction as the wind, the surface stress is reduced compared to under wind sea conditions. Using measurements from the Östergarnsholm site in the Baltic Sea, new expressions of the roughness length were developed for wind sea and swell. These new expressions were implemented in the RCA3 regional climate model covering Europe. A three-year simulation and two case studies using the wave field from the ECMWF reanalysis (ERA-40) were analysed using the improved formulations. Wind-following swell led to a significant reduction of mean wind stress and of heat fluxes. The mean surface layer wind speed was redistributed horizontally and the marine boundary layer cooled and dried slightly. This cooling was most pronounced over North Sea and the Norwegian Sea (almost 0.2°C annually on average) while the drying was most pronounced over the Mediterranean Sea (almost 0.4 g kg1). Somewhat less convective precipitation and low-level cloudiness over the sea areas were also indicated, in particular over the Mediterranean Sea. The impact on the atmosphere, however, is significantly locally greater in time and space.
Place, publisher, year, edition, pages
2009. Vol. 61, no 4, 527-538 p.
Earth and Related Environmental Sciences
Research subject Meteorology
IdentifiersURN: urn:nbn:se:uu:diva-115545DOI: 10.1111/j.1600-0870.2009.00403.xISI: 000267833000007OAI: oai:DiVA.org:uu-115545DiVA: diva2:295526