Intraseasonal Variability Associated with Summer Precipitation Over South America Simulated by 14 IPCC AR4 Coupled GCMs
Abstract
This study evaluates the intraseasonal variability associated with summer precipitation over South America in 14 coupled general circulation models (GCMs) participating in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Eight years of each model's twentieth-century climate simulation are analyzed. Two dominant intraseasonal bands associated with summer precipitation over South America are focused on: the 40- and the 22 day band. The results show that in the southern summer (November-April), most of the models underestimate seasonal mean precipitation over central-east Brazil, northeast Brazil, and the South Atlantic convergence zone (SAC2), while the Atlantic intertropical convergence zone (ITCZ) is shifted southward of its observed position. It is found that models with some form of moisture convective trigger tend to produce large variances for the intraseasonal bands.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2009
- Accession Number
- ADA509715
Entities
People
- B. Leibermann
- Jialin Lin
- Jiawei Zhou
- P. Roudy
- T. Qian
- Toshiaki Shinoda
- W. Han
- Yuan Zheng
Organizations
- United States Naval Research Laboratory