Tropical Pacific Influence on the Source and Transport of Marine Aerosols to West Antarctica
Author(s)
Criscitiello, Alison S.; Das, Sarah B.; Karnauskas, Kristopher B.; Evans, Matthew J.; Frey, Karen E.; Joughin, Ian; Steig, Eric J.; McConnell, Joseph R.; Medley, Brooke; ... Show more Show less
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The climate of West Antarctica is strongly influenced by remote forcing from the tropical Pacific. For example, recent surface warming over West Antarctica reflects atmospheric circulation changes over the Amundsen Sea, driven by an atmospheric Rossby wave response to tropical sea surface temperature (SST) anomalies. Here, it is demonstrated that tropical Pacific SST anomalies also influence the source and transport of marine-derived aerosols to the West Antarctic Ice Sheet. Using records from four firn cores collected along the Amundsen coast of West Antarctica, the relationship between sea ice–modulated chemical species and large-scale atmospheric variability in the tropical Pacific from 1979 to 2010 is investigated. Significant correlations are found between marine biogenic aerosols and sea salts, and SST and sea level pressure in the tropical Pacific. In particular, La Niña–like conditions generate an atmospheric Rossby wave response that influences atmospheric circulation over Pine Island Bay. Seasonal regression of atmospheric fields on methanesulfonic acid (MSA) reveals a reduction in onshore wind velocities in summer at Pine Island Bay, consistent with enhanced katabatic flow, polynya opening, and coastal dimethyl sulfide production. Seasonal regression of atmospheric fields on chloride (Cl[superscript −]) reveals an intensification in onshore wind velocities in winter, consistent with sea salt transport from offshore source regions. Both the source and transport of marine aerosols to West Antarctica are found to be modulated by similar atmospheric dynamics in response to remote forcing. Finally, the regional ice-core array suggests that there is both a temporally and a spatially varying response to remote tropical forcing.
Date issued
2014-02Department
Joint Program in Oceanography/Applied Ocean Science and Engineering; Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate; Woods Hole Oceanographic InstitutionJournal
Journal of Climate
Publisher
American Meteorological Society
Citation
Criscitiello, Alison S., Sarah B. Das, Kristopher B. Karnauskas, Matthew J. Evans, Karen E. Frey, Ian Joughin, Eric J. Steig, Joseph R. McConnell, and Brooke Medley. “Tropical Pacific Influence on the Source and Transport of Marine Aerosols to West Antarctica.” J. Climate 27, no. 3 (February 2014): 1343–1363. © 2014 American Meteorological Society
Version: Final published version
ISSN
0894-8755
1520-0442