Review of Recent Climate Conditions and Forecasts
Abstract

Abstract Author: Gerald Meehl

Abstract Title: Mechanisms of drought in present and future climate

Abstract: Long control runs, 20th century, and 21st century climate model simulations are analyzed to study mechanisms that produce persistent precipitation deficits and enhanced risk of drought over North America. As noted in previous studies, a combination of slowly varying SST anomalies in the tropical Pacific and Atlantic contribute to drought over North America in the model, with cooler than normal SST anomalies in the tropical Pacific and warmer than normal SST anomalies in the tropical Atlantic both playing a role. For future climate, the average climate change signal is one of enhanced risk of drought over western North America, although this occurs with warmer base SSTs in the both the tropical Pacific and Atlantic. We address the question of how these changes in base state SSTs in a future warmer climate affect the mechanisms that appear to produce drought over North America in present-day climate.