Impact of recent model improvements on GISS GCM predictions of climate change. Final technical report, September 15, 1992--September 14, 1994

摘要

The response of the 8 x 10(degree) horizontal resolution version of Model 2 to the forcing of globally observed SST (1980--1986) was evaluated. The simulations showed a realistic interannual variability of interhemispheric gradients of layer mean temperatures in response to observed SST gradients, but modeled near-surface winds over the Atlantic Ocean were much weaker than observed, a symptom of the Model 2 planetary boundary layer (PBL). In addition, the interannual variability of peak-season rainfall rates over Northeast Brazil (Nordeste) from the experiment was considerably smaller than the observed, although the observed negative association between seasonal Nordeste rainfall and interhemispheric Atlantic SST differences was weakly present. Preliminary experiments at 4 x 5(degree) resolution incorporating two of the new model parameterizations show more variability of the simulated Nordeste rainfall in response to the SST forcing, but only slight improvement in the correlation with observations.