This is a grant under a Climate Variability and Predictability (CLIVAR) Program pilot project called DRICOMP, for the Drought in Coupled Models Project, which focuses on making initial explorations into the mechanisms of drought as they are represented in the output of global climate models and on attempting to assess the reliability of these models in simulating drought.
The principal investigators will attempt to advance understanding of the genesis of long-term drought over North America, especially the continental United States, by analyzing its concurrent and antecedent links in sea surface temperatures (SST). The observed SST links will serve as the target in core assessments of drought mechanisms in model simulations of 20th century climate. The assessment is critical, as only mechanisms and not events can be validated in coupled climate simulations. The veracity of SST-drought links in 20th century simulations can generate confidence in model-based projections of U.S. drought incidence and intensity in a warming scenario. To facilitate this initial examination of a large number of model simulations and projections, a seasonal precipitation-based drought index will be devised to capture low-frequency hydroclimate variability.
The salient features of the analyses are: Development of precipitation-based drought index; all-season analysis of drought-SST links; evolution-centric depiction of combined SST-drought variability from extended-empirical orthogonal function (EOF) analysis; identification of recurrent modes of SST-drought variability, leading to quantification of basin influences and insights into extreme event occurrence; and examination of North American droughts in a warmer climate.
Broader impacts of these studies are in determining the credibility of Intergovernmental Panel on Climate Change (IPCC)models in simulating the evolution and mechanisms of drought.
