HR: 0830h
AN: C41C-0978    [PDF]
TI: The IGAC Air-Ice Chemical Interactions (AICI) Task and the IPY
AU: Wolff, E W
EM: ewwo@bas.ac.uk
AF: British Antarctic Survey, High Cross Madingley Road, cambridge, CB3 0ET United Kingdom
AU: * Shepson, P B
EM: pshepson@purdue.edu
AF: Purdue University, Department of Chemistry 560 Oval Dr., West Lafayette, IN 47907 United States
AB: The new structure of IGBP focuses on study of the three main compartments (land, ocean, and atmosphere) and the exchanges and interactions between them. The cryosphere - ice, snow and permafrost - occurs in all three of these compartments. It forms a large proportion of the surface separating the land and ocean from the atmosphere: a seasonal maximum of 40% of land is covered by snow or ice, while several percent of the ocean is sea-ice covered. Recent observations in the Arctic and in Antarctica indicate that the snowpack is photochemically active, producing and emitting to the atmosphere a variety of photochemically active compounds such as HCHO and other carbonyl compounds, NOx, HONO, molecular halogens, and alkyl halides, which can significantly impact the composition of the overlying atmosphere. It is known that ozone can be photochemically destroyed within the snowpack, and in the overlying atmosphere as a result of photochemistry involving halogen species generated within and emitted from the snowpack. Because global change will result in changes to snow cover, and because these processes are currently ill-defined and thus difficult to predict with accuracy, an international coordinated effort regarding the role of ice and snow in atmospheric composition is needed. We have created the Air-Ice Chemical Interactions (AICI) project, as a new task within the IGBP IGAC Project. In this paper, we will discuss AICI, its structure, function, and future plans, in relation to the following scientific questions: \begin{itemize}\item{How will changing amounts of sea ice, snow cover, and atmospheric ice alter atmospheric chemistry and composition and are there important feedbacks to climate?}\item{What are the present regional emissions and losses over snow, ice and sea ice, and how could they alter with changing climate?}\end{itemize} Until now, our knowledge of polar tropospheric chemistry has been limited to a few, mainly coastal sites. The IPY offers an opportunity for a coordinated effort to determine the spatial and seasonal structure of the phenomena that have been observed. This could be done through concerted observations at manned stations, from airborne platforms, and using a network of autonomous sensors deployed throughout the Arctic and Antarctic.
DE: 0368 Troposphere--constituent transport and chemistry
DE: 1030 Geochemical cycles (0330)
DE: 1610 Atmosphere (0315, 0325)
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2003 Fall Meeting