HR: 14:30h
AN: A23A-04    [Abstracts]
TI: Climatic Feedbacks during the 2003 European Heatwave
AU: * Fennessy, M J
EM: fen@cola.iges.org
AF: Center for Ocean-Land-Atmosphere Studies, 4041 Powder Mill Road Suite 302, Calverton, MD 20705-3106 United States
AU: Kinter, J L
EM: kinter@cola.iges.org
AF: Center for Ocean-Land-Atmosphere Studies, 4041 Powder Mill Road Suite 302, Calverton, MD 20705-3106 United States
AB: During the summer of 2003, a record heat wave over Europe occurred, to which the deaths of over 12,000 people in 18 countries were attributed, 10,000 of those in France alone. There were widespread wildfires, and the wildlife in the region was also dramatically affected, with high tolls being taken in the bird and fish populations. The Danube River reached its lowest level in more than a century, and Mediterranean Sea surface temperatures off the coast of Spain reached the highest levels observed in 45 years (32° C). Temperatures across Europe were above normal for most of the summer, but reached their peak during the first 2 weeks of August, when most of the deaths occurred. Ensemble simulations done with a recent version of the Center for Ocean-Land-Atmosphere Studies (COLA) atmospheric general circulation model (AGCM) have been analyzed over the European region. The simulations were forced by weekly mean observed sea-surface temperature (SST) obtained from the U.S. National Centers for Environmental Prediction (NCEP) and were initialized in late 1981. Relative to the 1982-2001 period, the COLA AGCM simulated anomalous warmth over the European region during June, July and August 2003, in response to the observed SST, however the simulated magnitude was smaller than observed. Additional simulations done with climatological SST verified that the simulated warmth was indeed related to SST. A series of simulations in which the observed SST was used only south of 25N or only north of 25N suggest that it was the influence of the local SST rather than remote SST that was an important influence on the heatwave. Analysis of the near real-time calculated global soil wetness provided by NCEP reveals that by early June the soil over much of the European region was anomalously dry, which is consistent with the below normal precipitation observed over the region in the preceding months. The soil wetness anomalies obtained from NCEP were adapted for use in the COLA AGCM and the model was restarted in early June with the resultant anomalies imposed on the soil wetness from the control simulations. Although the model soil wetness was then allowed to evolve as usual, the simulations with the imposed initial soil wetness anomaly enhanced the simulated surface temperature anomaly during June, July and August by 1-2° C. The experiments suggest that both the warm local SST and the dry local soil were important in intensifying the 2003 European heat wave.
DE: 0315 Biosphere/atmosphere interactions
DE: 1833 Hydroclimatology
DE: 1854 Precipitation (3354)
DE: 1866 Soil moisture
DE: 4504 Air/sea interactions (0312)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly