The Antarctica Plateau: A New Look at Boundary Layer Atmospheric Chemistry
Douglas D. Davis, Georgia Institute of Technology
Within the last decade there has been a growing interest in the atmospheric chemical processes occurring in polar environments. Reflecting this, enhanced levels of halogens have been reported along the coasts of polar regions as well abrupt decreases in the levels of ozone. Further inland, significant concentrations of oxygenated hydrocarbons, especially formaldehyde (CH2O), have been observed along with peroxides and nitrogen oxides. In fact, emissions of the latter species from snow now appear to be the basis for observed highly elevated measured levels of the atmospheres most important oxidizing agent, the hydroxyl radical (OH). Nowhere has this newly discovered polar chemistry had such a widespread impact as now being observed on the Antarctic plateau. Following the first plateau observations at South Pole in 1998, there now have been numerous follow-on studies. These have revealed frequent cases of highly elevated levels of NO (e.g., ~500 pptv) along with corresponding elevated levels of the oxidation products HNO_3 and HO_2 NO_2 occurring in shallow stable boundary layers. More recent airborne observations suggest that during the spring/summer months most if not all of the plateau planetary boundary layer (regional dimensions ~ continental USA) is highly oxidizing, having major photochemical enhancements in both OH and O_3 . To be discussed are some of the latest research results from this unique environment which have provided yet additional surprises.
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