Seasonally resolved ice core records from West Antarctica indicate a sea ice source of sea-salt aerosol and a biomass burning source of ammonium
Pasteris, Daniel R.
McConnell, Joseph R.
Das, Sarah B.
Criscitiello, Alison S.
Evans, Matthew J.
Maselli, Olivia J.
MetadataShow full item record
The sources and transport pathways of aerosol species in Antarctica remain uncertain, partly due to limited seasonally resolved data from the harsh environment. Here, we examine the seasonal cycles of major ions in three high-accumulation West Antarctic ice cores for new information regarding the origin of aerosol species. A new method for continuous acidity measurement in ice cores is exploited to provide a comprehensive, charge-balance approach to assessing the major non-sea-salt (nss) species. The average nss-anion composition is 41% sulfate (SO42−), 36% nitrate (NO3−), 15% excess-chloride (ExCl−), and 8% methanesulfonic acid (MSA). Approximately 2% of the acid-anion content is neutralized by ammonium (NH4+), and the remainder is balanced by the acidity (Acy ≈ H+ − HCO3−). The annual cycle of NO3− shows a primary peak in summer and a secondary peak in late winter/spring that are consistent with previous air and snow studies in Antarctica. The origin of these peaks remains uncertain, however, and is an area of active research. A high correlation between NH4+ and black carbon (BC) suggests that a major source of NH4+ is midlatitude biomass burning rather than marine biomass decay, as previously assumed. The annual peak in excess chloride (ExCl−) coincides with the late-winter maximum in sea ice extent. Wintertime ExCl− is correlated with offshore sea ice concentrations and inversely correlated with temperature from nearby Byrd station. These observations suggest that the winter peak in ExCl− is an expression of fractionated sea-salt aerosol and that sea ice is therefore a major source of sea-salt aerosol in the region.
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Atmospheres 119 (2014): 9168–9182, doi:10.1002/2013JD020720.
Showing items related by title, author, creator and subject.
Accounting for biological and physical sources of acoustic backscatter improves estimates of zooplankton biomass Warren, Joseph D.; Wiebe, Peter H. (2007-09-26)In order to convert measurements of backscattered acoustic energy to estimates of abundance and taxonomic information about the zooplankton community, all of the scattering processes in the water column need to be identified ...
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 (American Meteorological Society, 2014-02-01)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, ...
Spatial and isotopic niche partitioning during winter in chinstrap and Adélie penguins from the South Shetland Islands Hinke, Jefferson T.; Polito, Michael J.; Goebel, Michael E.; Jarvis, Sharon; Reiss, Christian S.; Thorrold, Simon R.; Trivelpiece, Wayne Z.; Watters, George M. (Ecological Society of America, 2015-07-29)Closely related species with similar ecological requirements should exhibit segregation along spatial, temporal, or trophic niche axes to limit the degree of competitive overlap. For migratory marine organisms like seabirds, ...