Subtropical Gyres: Formation, Dynamics, and Climatology

Suny At Albany, Albany NY

Investigators

Abstract

This is a project to study subtropical gyres, which are lower-tropospheric cyclones occurring between 12N and 30N in northern summer, especially in the western North Pacific. They are larger than tropical cyclones (TCs), and sometimes contain TCs that form within them and propagate cyclonically around them. The work will investigate the origin, climatology, structure, and dynamics of the gyres, and study their spatial and temporal distribution and their contribution to precipitation and TC genesis. The project begins by determining an appropriate set of criteria to define subtropical gyres, so that an automated process can be used to create a record of them, to be used to determine their spatial and seasonal distribution, typical size and duration, and variations associated with El Nino and events and the Madden-Julian Oscillation. Next, the research will focus on the structure, evolution, and dynamics of subtropical gyres. In addition to the observational record, the research will use simulations from the Weather Research and Forecasting (WRF) model to examine the contributions of various physical mechanisms to gyre evolution, including the surface wind response to diabatic heating associated with convection within the gyre, and the subsequent enhancement of surface heat exchange on the western side of the gyre. Research on subtropical gyres has societal value given the association of the gyres with TC formation. Typhoons forming within subtropical gyres pose a threat to the coastal regions of East and Southeast Asia, and the work performed under this award may contribute to better understanding and prediction of these storms. In addition, the project supports a graduate student and thus contributes to the next generation of researchers in this scientific area.