Concept information
Preferred term
ISCAT
Definition
- Research Objectives of the Investigation of Sulfur Chemistry in Antarctic Troposphere (ISCAT): During this four-year study at Amundsen-Scott South Pole Station, we will examine the sulfur chemistry of the Antarctic atmosphere. The study involves two field seasons, the first of which was completed in 1998-1999. This field season (2000-2001) will be the second and last for this project. The study, which includes 10 principal and senior investigators at five institutions, with seven additional contributing investigators, has two broad-based goals: to improve substantially our current understanding of the oxidation chemistry of bioorganic sulfur in the polar environment, and to improve the climatic interpretation of sulfur-based signals in Antarctic ice-core records. The South Pole was selected because the atmospheric boundary layer at this site presents a homogeneous and relatively simple environment from which to unravel the photochemically driven oxidation chemistry of dimethyl sulfide. Atmospheric sulfur chemistry is an important component in climate change issues because both naturally (i.e., from volcanic emissions and oceanic phytoplankton production) and anthropogenically emitted sulfur compounds form minute particles in the atmosphere--the so-called aerosols--that reflect solar radiation, produce atmospheric haze and acid rain, and affect ozone depletion. Sulfate particles in the atmosphere may also act as condensation nuclei for water vapor and enhance global cloudiness. On the millennial time scale, the variability and natural background level of atmospheric aerosols can be reconstructed from the preserved paleorecords of sulfur oxidation products in ice cores. It is necessary, however, to understand how the physical and chemi! cal environment of the oxidation process affects the relative concentrations of the oxidation products that become buried in the ice. This study requires simultaneous observations of a wide-ranging suite of sulfur species, such as DMS and its oxidation products, sulfur dioxide, dimethyl sulfoxide, dimethyl sulfone, methane sulfonic acid, and sulfuric acid, as well as photochemically important compounds such as carbon monoxide, nitrous oxide, water vapor, and non-methane hydrocarbons. Secondary objectives will be: to examine interior Antarctic air samples for other significant DMS oxidation products, such as sulfurous acid and methane sulfonic acid; and to assess the local variation in hydroxyl and perhydroxyl radicals, a measure of the oxidizing power of the atmosphere. This study will provide, for the first time, a quantitative picture of exactly which atmospheric sulfur compounds are advected into the Antarctic interior and a detailed picture of the sulfur chemistry that is active in the Antarctic atmosphere. Contact Information: Dr. Douglas Davis, Principal Investigator Georgia Institute of Technology School of Earth and Atmospheric Sciences 221 Bobby Dodd Way Atlanta, GA 30332-0340 Phone: 404-894-4008 Fax: 404-894-1993 Email: douglas.davis@eas.gatech.edu For more information, link to "http://rpsc.raytheon.com/science/SciPlanSummaries/sps00/00_OO_270_O.htm" [Summary provided by Raytheon] (en)
Broader concept
- G - I (en)
URI
https://gcmd.earthdata.nasa.gov/kms/concept/5428112b-5938-4065-ad13-72c9c2637cc1
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