Large-Scale Influences on Tropical Cyclogenesis

Suny At Albany, Albany NY

Investigators

Abstract

The objective of this project is to study tropical cyclongenesis and, in particular, what roles different environmental flows play in it. Three research avenues will be pursued. The first one is to examine tropical cyclogenesis in the eastern Pacific using data from the East Pacific Investigation of Climate Processes (EPIC) experiment in which the PI actively participated and the Outgoing Long-wave Radiation (OLR) data from NOAA. The focus will be the relationship between the intertropical convergence zone (ITCZ) and easterly waves before tropical cyclones form. For the second avenue, the PI will attempt to reconcile two paradigms of tropical cyclogenesis in the western Pacific and Gulf of Mexico, namely, the spin-up of vortices in the monsoon trough versus easterly waves interacting with the Madden Julian Oscillation (MJO) as pre-cursors to cyclogenesis. The working hypothesis is that tropical cyclogenesis often occurs under the following circumstances: 1) an active MJO producing a strong monsoon trough with westerlies to its south and 2) upstream waves reach the active MJO, grow in amplitude, and are ultimately the locus of depression formation. In this way, the MJO, monsoon trough, and upstream waves all participate and interact in cyclone formation. The third avenue is to conduct numerical simulations using shallow water and barotropic models to test the working hypothesis, using both idealized background states and those extracted from observational data with MJO signals. Tropical cyclogenesis remains one of the most challenging tasks in weather prediction. Increasing the understanding of how environmental flows affect genesis is important both from the prediction and modeling perspectives. The planned research has the potential of shedding some light in this area and the research will provide good opportunities for graduate studies.