RAPID: Drought Risk and Low-frequency Hydroclimatic Variability in CMIP5 Simulations

University Of Arizona, Tucson AZ

Investigators

Abstract

This is one of 16 Rapid Response (RAPID) projects funded as the result of a Dear Colleague Letter (NSF 11-006) encouraging diagnostic analyses of climate model simulations prepared for the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Research conducted in these projects is expected to lead to more detailed model intercomparisons, better understanding of robust model behaviors, and better understanding and quantification of uncertainty in future climate simulations. This project considers the extent to which model simulations prepared for AR5 are capable of reproducing the low-frequency hydroclimate variability found in the instrumented and paleo-proxy records. The earlier generation of models used in the IPCC Fourth Assessment Report (AR4) was found to be deficient in capturing low-frequency hydroclimate variability, and this deficiency could mean that future projections from the models underestimate the risk of prolonged drought in regions including the US southwest. Research conducted here seeks to determine if the current generation of models produces more realistic low-frequency hydroclimate variance. In addition, methods are developed to rescale drought projections from the models to produce observationally corrected estimates of future drought risk. The broader impact of the project lies in its support of the IPCC AR5, which is intended to provide information on climate change and its consequences to decision makers worldwide. Hydroclimate variability and change are of great societal interest given their large impacts on people, agriculture, and ecosystems. This is particularly true in southwestern North America, a focus region for the research.