Future wind climate in the Baltic Sea region
Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
The purpose with this work is to analyze the wind field in the Baltic Sea region using three atmosphere-ocean general circulation models (AOGCM). The AOGCMs: ECHAM5, CCSM3 and HadCM3 have been downscaled with a regional climate model RCA3 and two 30-yr climate periods have been compared and analyzed: 1961-1990 and 2071-2100 representing present and future climate. The climate scenarios used in this work are based on the Special Report on Emission Scenario (SRES). Climate scenario A1B has three runs from ECHAM5 and one each from HadCM3 and CCSM3, A2 and B1 one run each for ECHAM5. The 1961-1990 period has also been compared to the
re-analysis data from ERA-40. The Baltic Sea region is focused with special interest in five specific basins: Bothnian Bay, Bothnian Sea, Eastern Gotland basin, Bornholm basin and Kattegat. For present wind climate most interesting result is in Bothnian Bay where all AOGCMs exceed ERA-40 with 22-48% for seasonal mean wind speed during December-February (DJF). CCSM3 estimates in Bornholm basin and Kattegat during DJF a 26-33% overestimation that is more than 14% more than the other AOGCMs for those two basins. In simulated future wind climate there is an overall wind speed increase in the Baltic Sea region. Also here, Bothnian Bay shows interesting results by an increase from the reference period in the seasonal mean wind speed in DJF and March-May (MAM) from ECHAM5 by 19-29% and 28% from HadCM3 in MAM. The higher wind speed simulated in Bothnian Bay might be a cause from the AOGCMs ability to simulate ice. Other similar studies explained that the increase in northern Baltic Sea might be a cause from the different models ability to simulate sea ice.
If the ice cover is underestimated or have been lost in the runs, it can in combination with an increase in the SST lead to changes in the stability in the lower-most atmosphere. This may lead to increased wind speed close to the surface. The A2 and B1 scenario for ECHAM5 show no particular difference from the A1B scenario for future wind climate. The increased mean wind speed over a 30-year period is clear over the Baltic Sea region but not over the land areas around it.
Place, publisher, year, edition, pages
2010. , 45 p.
Examensarbete vid Institutionen för geovetenskaper, ISSN 1650-6553
Wind climate in Baltic Sea, wind climate, global circulation models, Baltic Sea
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:uu:diva-132004OAI: oai:DiVA.org:uu-132004DiVA: diva2:356504
UppsokPhysics, Chemistry, Mathematics
Rutgersson, AnnaCarlsson, Björn