Simulating Multi-Season Past Droughts
Abstract

Abstract Author: Ian Ferguson

Abstract Title: 20th Century Drought Characteristics in Coupled Climate Simulations

Abstract: Coupled general circulation models (CGCMs) have many potential applications in drought research; however, simulated drought characteristics have not been thoroughly evaluated. Here we evaluate key precipitation and drought characteristics in 20th century simulations from 15 CGCMs from the IPCC’s Fourth Assessment Report. We find no significant difference between simulated and observed distributions of drought duration and severity over most land regions. However, models tend to overestimate duration and severity over India and Asia, Southern Africa, Brazil, and the US Great Plains and West Coast; models tend to underestimate duration and severity over central Australia, Indonesia, northern Africa, and high northern latitudes. Biases in duration and severity generally coincide with biases in the autocorrelation and low frequency variability of simulated precipitation anomalies, which may stem from errors in simulated SST variability. Results are discussed with respect to the use of CGCMs in drought research.