HR: 11:05h
AN: A52A-04 [Abstracts]
TI: On the Seasonal and Annual Variability of Saharan Mineral Dust in the Caribbean
AU: * Doherty, O M
EM: odoherty@ic.sunysb.edu
AF: Stony Brook University
Marine Sciences Research Center, Nicolls Rd, Stony Brook, NY 11794, United States
AU: Riemer, N
EM: nicole.riemer@stonybrook.edu
AF: Stony Brook University
Marine Sciences Research Center, Nicolls Rd, Stony Brook, NY 11794, United States
AU: Hameed, S
EM: sultan.hameed@stonybrook.edu
AF: Stony Brook University
Marine Sciences Research Center, Nicolls Rd, Stony Brook, NY 11794, United States
AB:
Dust plumes originating in North Africa span the tropical Atlantic, depositing their load over large expanses,
including the Caribbean and Gulf of Mexico. Mineral dust aerosols are known to play an important role in the
climate system, affect cloud properties and impact many oceanic biogeochemical cycles. The seasonal and
annual export of mineral dust is highly variable and controlled by large scale circulation patterns. Thus it is
important to identify the key constituents of the large scale circulation that control dust export if we are to
understand the impacts of mineral dust.
In a new approach, we ascribe changes in the large scale circulation to the movement and strength of major
"Centers of Action." We compare the atmospheric variability to variability found in TOMS/NIMBUS-7 and
TOMS/Earth Probe satellite aerosol data over the Caribbean Basin.
We find an increasing trend in the quantity of mineral dust over the Caribbean during the 1980s, with elevated
dust levels extending into the 21st century. Furthermore, the yearly duration of the time in which dust is present in
the Caribbean has been drastically increasing. We show that both increased emissions and changes in
transport patterns contribute to the observed trend.
By use of the "Centers of Action" approach we identify the longitudinal displacement and the pressure of the
Hawaiian High and the longitudinal displacement of the Azores High as key players, with the Hawaiian High
being especially important for intense dust events in the Caribbean.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly