Changes to Madden-Julian Oscillation Winds and Convection in a Future Warmer Climate

Colorado State University, Fort Collins CO

Investigators

Abstract

The Madden-Julian oscillation is a phenomenon of slowly eastward moving large-scale tropical convection system thousands of miles across over the equatorial Indian Ocean and Pacific. It affects the formation of hurricanes and tropical storms by interacting with disturbances over Gulf of Mexico, Caribbean Sea, and tropical Atlantic Ocean. The Madden-Julian oscillation is also capable of producing alternating high and low pressure patterns over the north Pacific Ocean and the United States, responsible for heavy rainfall events, droughts, cold air outbreaks, and other extreme weather events that affect lives and property. Such long-distance impacts of the Madden-Julian oscillation provide useful forecast skill for extreme weather over the U.S. up to a few weeks in advance. This project will explore if the Madden-Julian oscillation connections to the United States may potentially weaken or shift geographically in a warmer climate, which would have substantial implications for forecasts and for society. This project will support a graduate student and a postdoctoral researcher. Undergraduate students will also be involved in this research through a summer internship program conducted at Colorado State University. This project will use a set of climate model simulations to analyze how the Madden-Julian oscillation and its connections to the United States may change in a future warmer climate. Idealized models with reduced complexity will be used to identify and understand the underlying mechanisms responsible for these changes. Foci will be how changes in the stratification of the tropical atmosphere, and the position and strength of jet streams affect the ability of the Madden-Julian oscillation to impact weather in mid-latitudes. Whether the impacts of El Nino on United States weather may change in a warmer climate will also be examined. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.