HR: 0800h
AN: H51B-0461    [Abstracts]
TI: Linking Atmospheric Deposition to Air Mass Chemistry at a Coastal Rural Site
AU: * McDowell, W H
EM: bill.mcdowell@unh.edu
AF: Department of Natural Resources, 215 James Hall 56 College Rd., Durham, NH 03824, United States
AU: Daley, M L
EM: michelle.daley@unh.edu
AF: Department of Natural Resources, 215 James Hall 56 College Rd., Durham, NH 03824, United States
AU: Sive, B C
EM: bcs@ccrc.sr.unh.edu
AF: Climate Change Research Center, Institute for the Study of Earth, Oceans, and Space Morse Hall, Durham, NH 03824, United States
AU: Talbot, R W
EM: robert.talbot@unh.edu
AF: Climate Change Research Center, Institute for the Study of Earth, Oceans, and Space Morse Hall, Durham, NH 03824, United States
AB: Atmospheric deposition often provides a large part of the total nitrogen and organic matter entering surface waters, but the relationship between deposition and air mass chemistry is not well understood for many constituents. Wet deposition (WD) samples were collected at the Thompson Farm atmospheric observatory in coastal New Hampshire in conjunction with the AIRMAP program from November 2003 to January 2007. Samples were analyzed for DOC, TDN, DON, NO₃, NH₄, PO₄, Cl, SO₄, Oxalate, Na, K, Mg, Ca and SiO₂. DOC and Cl were the dominant constituents in wet deposition and inorganic nitrogen species dominated wet N deposition. Constituents in wet deposition were compared to various metrics of average daily atmospheric chemistry (AC) occurring on the day of the wet deposition event using canonical correlation analysis (CCA) to infer sources of wet deposition. Atmospheric chemistry metrics included continuous measures of air quality, aerosols and various volatile organic compounds (VOCs). Three WD canonical variates (CVs) were significantly related (p<0.05) to three AC CVs and together could explain 62% of the variation in WD constituents. The AC CV loaded with VOCs mostly of biogenic origin explained 20.4% of the variation in the first WD CV loaded with DOC, TDN and NH₄. The AC CV loaded with parameters representing urban or 2° processed air explained 30.8% of the variation in the second WD CV loaded with TDN, NH₄, NO₃ and SO₄. The AC CV representing a mixture of ocean, urban and biogenic sources explained 11.0% of the variation in the third WD CV loaded with Na and Cl. Our results suggest that interaction with urban/processed air masses drives temporal variation in wet deposition of most solutes, but DOC deposition is driven more by biogenic sources.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
DE: 1854 Precipitation (3354)
SC: Hydrology [H]
MN: 2007 Fall Meeting