The fate of Saharan dust across the Atlantic and implications for a Central American dust barrier

E. Nowottnick; P. Colarco; A. da Silva; D. Hlavka; M. McGill

doi:10.5194/acp-11-8415-2011

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The fate of Saharan dust across the Atlantic and implications for a Central American dust barrier

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The fate of Saharan dust across the Atlantic and implications for a Central American dust barrier

E. Nowottnick, P. Colarco, A. da Silva, D. Hlavka and M. McGill

Atmospheric chemistry and physics, Vol.11(16), pp.8415-8431

2011

DOI: 10.5194/acp-11-8415-2011

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Abstract

Saharan dust was observed over the Caribbean basin during the summer 2007 NASA Tropical Composition, Cloud, and Climate Coupling (TC (super 4) ) field experiment. Airborne Cloud Physics Lidar (CPL) and satellite observations from MODIS suggest a barrier to dust transport across Central America into the eastern Pacific. We use the NASA GEOS-5 atmospheric transport model with online aerosol tracers to perform simulations of the TC (super 4) time period in order to understand the nature of this barrier. Our simulations are driven by the Modern Era Retrospective-Analysis for Research and Applications (MERRA) meteorological analyses. Compared to observations from MODIS and CALIOP, GEOS-5 reproduces the observed location and magnitude of observed dust events, but our baseline simulation does not develop as strong a barrier to dust transport across Central America as observations suggest. Analysis of the dust transport dynamics and loss processes suggest that while both mechanisms play a role in defining the dust transport barrier, loss processes by wet removal of dust are about twice as important as transport. Sensitivity analyses with our model showed that the dust barrier would not exist without convective scavenging over the Caribbean. The best agreement between our model and the observations was obtained when dust wet removal was parameterized to be more aggressive, treating the dust as we do hydrophilic aerosols.

absorption

aerosols

Africa

airborne methods

Atlantic Ocean

atmospheric precipitation

atmospheric transport

Caribbean region

Caribbean Sea

Central America

clastic sediments

climate change

convection

dust

East Pacific

Environmental geology

GEOS-5 model

intertropical convergence zone

La Nina

laser methods

lidar methods

meteorology

MODIS

nonpoint sources

North Atlantic

Pacific Ocean

remote sensing

Sahara

Sahel

satellite methods

sediments

solar radiation

spatial distribution

tracers

transport

winds

Details

Title: Subtitle: The fate of Saharan dust across the Atlantic and implications for a Central American dust barrier
Creators: E. Nowottnick - University of Maryland, College Park
P. Colarco - Goddard Space Flight Center
A. da Silva - Goddard Space Flight Center
D. Hlavka - Goddard Space Flight Center
M. McGill - Goddard Space Flight Center
Resource Type: Journal article
Publication Details: Atmospheric chemistry and physics, Vol.11(16), pp.8415-8431
DOI: 10.5194/acp-11-8415-2011
ISSN: 1680-7316
eISSN: 1680-7324
Publisher: Copernicus
Language: English
Date published: 2011
Academic Unit: Physics and Astronomy; Chemical and Biochemical Engineering
Record Identifier: 9984276454902771

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