HR: 16:30h
AN: B54A-03    [Abstracts]
TI: Processing of Atmospheric Nitrogen by Clouds in a Forest Environment
AU: * Hill, K A
EM: kahill23@purdue.edu
AF: Department of Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 United States
AU: Shepson, P B
EM: pshepson@purdue.edu
AF: Department of Earth and Atmospheric Sciences, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907 United States
AU: Shepson, P B
EM: pshepson@purdue.edu
AF: Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907 United States
AU: Galbavy, E S
EM: esgalbavy@ucdavis.edu
AF: Department of Land, Air and Water Resources, Univeristy of California-Davis, One Shields Avenue, Davis, CA 95616 United States
AU: Anastasio, C
EM: canastasio@ucdavis.edu
AF: Department of Land, Air and Water Resources, Univeristy of California-Davis, One Shields Avenue, Davis, CA 95616 United States
AB: Forest growth is usually limited by nitrogen availability, so an enhancement in nitrogen input to trees can fertilize and boost a forest's ability to take up CO₂, potentially influencing global climate change. Wet deposition by precipitation and fog may account for up to 80-95% of total nitrogen deposition in some locations, while elsewhere wet and dry nitrogen deposition are nearly equal. The role of clouds in processing atmospheric nitrogen before deposition remains to be thoroughly studied. Clouds over forest environments may provide reaction surfaces and act as photochemical reactors for water-soluble nitrogen compounds, thus altering the amounts and species of nitrogen deposited by both wet and dry deposition to the forest. This study investigated the role of clouds and cloud chemistry in the nitrogen cycle in a forest environment through the use of aircraft-based cloud water sampling and cloud water analysis. Cloud water samples were analyzed for inorganic and organic nitrogen content. Cloud water was collected over northern Michigan using a modified Mohnen slotted rod collector. Flights were conducted from June to September 2005 in both stratus and cumulus clouds and at varying altitudes within the cloud fields. The samples were analyzed for nitrate, ammonium, and organic nitrogen concentrations. The results of these analyses as well as variations in the concentrations of each nitrogen species with altitude will be discussed.
DE: 0320 Cloud physics and chemistry
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0469 Nitrogen cycling
SC: Biogeosciences [B]
MN: Fall Meeting 2005