HR: 10:30h
AN: A22A-01    [Abstracts]
TI: Simulation of 20th Century Climate Change in the GFDL Coupled Models
AU: * Delworth, T L
EM: tom.delworth@noaa.gov
AF: GFDL/NOAA, PO Box 308 Princeton University, Princeton, NJ 08542 United States
AU: Knutson, T R
EM: tom.knutson@noaa.gov
AF: GFDL/NOAA, PO Box 308 Princeton University, Princeton, NJ 08542 United States
AU: Lu, J
EM: jian.lu@noaa.gov
AF: UCAR Visiting Scientist/GFDL, PO Box 308 Princeton University, Princeton, NJ 08542 United States
AB: Ensembles of simulations for the 20th century have recently been conducted at GFDL as part of the 2007 IPCC process. The simulations were conducted with two new climate models recently developed at GFDL. The new models (CM2.0 and CM2.1) consist of recently developed atmospheric, oceanic, sea ice, and land component models, and do not use flux adjustments. The models simulate current climate in a realistic manner, including a substantially improved simulation of ENSO relative to previous models. Several aspects of 20th century climate change are examined. In the first we assess to what degree trends in surface air temperature simulated in the model are consistent with observations, and to what extent they are attributable to anthropogenic forcings. These assessments are done on both a global and regional basis. In addition, we examine simulations of the Sahelian drought in the latter half of the 20th century. Drought over the Sahel emerges in these coupled model simulations as a response to anthropogenic forcing, and is inconsistent with internal variability as estimated from the coupled model. The simulated drought has approximately half the amplitude of the observed drought. Diagnostics relevant to the simulated Sahelian drought are presented, including the relationship between the drought and global SST patterns.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
DE: 1635 Oceans (4203)
DE: 1812 Drought
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly