SEMINAR: MPO Seminar: Dr. Lisa Murphy, TODAY, at 3:00 p.m., Slab Seminar room, S/A 103

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

MPO Seminar

Dr. Lisa Murphy

Title" Changes in atmospheric dust in response to Heinrich events"

Date: Wednesday, January 30, at 3:00 p.m.

Room: Slab Seminar Room, S/A 103 

abstract:

Heinrich Events (HE) are generally thought to be triggered by increased ice discharge in the high latitude North Atlantic at glacial periods, which resulted in large fresh water forcing that weakened the Atlantic Meridional Overturning Circulation (AMOC). These events are strongly expressed in paleoclimate records throughout the Atlantic basin, and throughout much of the tropics. Recent proxy data suggest HE were much dustier than the LGM with widespread tropical drought. We use a state-of-the-art global climate model coupled to a dust source, transport and deposition model to examine the response of atmospheric dust to changes in climate associated with HE. We find that atmospheric dynamical changes have a bigger effect on dust mobilization than hydrological changes associated with a reduction in AMOC. Although Europe is colder and drier during HE, glaciogenic dust sources over are weakened due to weaker winds associated with a southward shift in the Northern Hemisphere (NH) midtropospheric jets. In contrast dust emissions from the Central US are intensified throughout the year, which results in more deposition over the Western North Atlantic.  Although a southward shift in the ITCZ in response to an AMOC shutdown creates drier conditions over North Africa, gustiness is decreased in summer, leading to less emission and deposition over the North Tropical Atlantic. 

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