HR: 17:15h
AN: A14C-05    [Abstracts]
TI: Towards an Understanding of Atmospheric Methanol
AU: * Millet, D B
EM: dbm@io.harvard.edu
AF: Harvard University, 29 Oxford St, Cambridge, MA 02138,
AU: Jacob, D J
EM: djj@io.harvard.edu
AF: Harvard University, 29 Oxford St, Cambridge, MA 02138,
AU: de Gouw, J
EM: Joost.deGouw@noaa.gov
AF: NOAA-ESRL, 325 Broadway, Boulder, CO 80305,
AU: Warneke, C
EM: carsten.warneke@noaa.gov
AF: NOAA-ESRL, 325 Broadway, Boulder, CO 80305,
AU: Holloway, J S
EM: john.s.holloway@noaa.gov
AF: NOAA-ESRL, 325 Broadway, Boulder, CO 80305,
AU: Blake, D R
EM: drblake@uci.edu
AF: UC Irvine, 570 Rowland Hall, Irvine, CA 92697,
AU: Karl, T
EM: tomkarl@ucar.edu
AF: NCAR, P.O. Box 3000, Boulder, CO 80307,
AU: Campos, T
EM: campos@ucar.edu
AF: NCAR, P.O. Box 3000, Boulder, CO 80307,
AU: Singh, H B
EM: Hanwant.B.Singh@nasa.gov
AF: NASA-Ames, MS 245-5, Moffett Field, CA 94035,
AU: Diskin, G S
EM: g.s.diskin@larc.nasa.gov
AF: NASA-Langley, MS 483, Hampton, VA 23681,
AB: Methanol, the most abundant non-methane organic gas in the atmosphere, is an important global source of tropospheric CO and formaldehyde, and plays a significant role in the tropical HOx and ozone budgets. The atmospheric methanol budget is highly uncertain, with estimates of the global source ranging from 75 to 490 Tg/yr. New measurements from recent field experiments (INTEX-B, MILAGRO, TEXAQS-II, INTEX-A, and ICARTT) provide quantitative constraints on methanol sources and sinks. Here we use a 3D model of atmospheric chemistry (GEOS-Chem) to interpret these datasets and their implications for the global methanol budget. We find that emissions from terrestrial plants (thought to be the main source) are overestimated by 40-50%; the discrepancy appears specific to certain plant functional types (broadleaf trees and crops). Recent measurements in the surface ocean imply a large in situ biotic source, so that methanol emissions from the ocean biosphere are comparable in magnitude to those from terrestrial ecosystems. The oceans are also a large gross sink for atmospheric methanol (similar to oxidation by OH). Even with the plant growth source decreased by 40-50% according to these new constraints, we find that methanol emissions from the terrestrial biosphere still dominate over those from urban and industrial sources, in contrast to other recent studies.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting