Dynamics and Transport in the Tropospheric Equatorial Westerly Ducts

Johns Hopkins University, Baltimore MD

Investigators

Abstract

The project will investigate the dynamical interactions and tracer transports between the tropics and midlatitudes, especially during Northern winter. The equatorial upper troposphere is occupied by a belt of easterlies during much of the year, except winter, when westerly winds are present over the central/eastern oceans. The easterlies are an effective barrier for equatorward propagating stationary Rossby waves, and the wintertime "westerly duct" thus presents an opening that allows vigorous tropical-extratropical interaction. Dr. Waugh will conduct a dynamically oriented analysis of meteorological fields and water vapor observations to understand how tropical-extratropical interactions through this conduit impact tropical convection, and the upper tropospheric distribution of water vapor (a major component in global warming), ozone, and trace gases. These trace substances exert a profound control on the earth's climate, directly through radiative impacts, and indirectly, through the altered balanced circulation. Dr. Waugh will use a range of dynamical and transport models to provide context for his observational findings.