SEMINAR: MPO Seminar:Prof. John Molinari, TODAY, at 3:00 p.m., Slab Seminar room, S/A 103

[Sandrine Apelbaum <sapelbaum@rsmas.miami.edu>]

MPO Seminar

Prof. John Molinari

SUNY Albany

"Origin and Structure of Large Cyclonic Circulations in the Subtropical Pacific""

 

Room: S/A 103

Date: Wednesday, March 21, at 3:00 p.m. 

Abstract:

Enormous low pressure areas, often called “cyclonic gyres”, develop in the northwest Pacific during boreal summer. The diameter of azimuthally averaged cyclonic flow in the lower troposphere in these disturbances exceeds 4000 km. The gyres are typically cloud-free in the center and on their poleward side, but have convection to their south that covers thousands of km in longitude. Gale-force winds can extend more than 1000 km from the center. Tropical cyclones often form on their edges and move cyclonically around the larger circulation. The seminar will address the formation and structure of these disturbances. Most have their roots in the upstream MJO. This influence is not direct, but acts through MJO modification of the middle latitude upper tropospheric jet over northeast Asia and subsequent anticyclonic wave breaking over the Pacific. These wave breaking events excite subtropical convection and leave behind a region of cyclonic vorticity that forms the seedling for the gyre. The gyres seem to form near the same location northeast of the Philippines, almost always in July or August, and almost always during La Nina events. The interrelationships among the MJO, the midlatitude jet, events in the subtropics, and ENSO will be discussed.

Sandrine Apelbaum

Meteorology and Physical Oceanography 
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149-1098
Tel     (305) 421-4057
Fax     (305) 421-4696

sapelbaum@rsmas.miami.edu