HR: 09:45h
AN: OS11C-08    [Abstracts]
TI: Measurements and Models of Oceanic $O_2$ and $CO_2$ Fluxes
AU: * Battle, M
EM: mbattle@bowdoin.edu
AF: Bowdoin College, Dept. of Physics and Astronomy 8800 College Station, Brunswick, ME 04011 United States
AU: Fletcher, S M
EM: fletcher@igpp.ucla.edu
AF: University of California, Los Angeles, Institute of Geophysics and Planetary Sciences,, Los Angeles, CA 90095 United States
AU: Bender, M
EM: bender@princeton.edu
AF: Dept. of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544 United States
AU: Keeling, R
EM: rkeeling@ucsd.edu
AF: Scripps Institute of Oceanography, University of California, San Diego, La Jolla, CA 92093 United States
AU: Gruber, N
EM: ngruber@igpp.ucla.edu
AF: University of California, Los Angeles, Institute of Geophysics and Planetary Sciences,, Los Angeles, CA 90095 United States
AU: Tans, P P
EM: pieter.tans@noaa.gov
AF: National Oceanic and Atmospheric Administration, Climate Monitoring and Diagnostics Laboratory, Boulder, CO 80303 United States
AU: Hendricks, M B
EM: mhendric@princeton.edu
AF: Dept. of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544 United States
AU: Ho, D T
EM: david@ldeo.columbia.edu
AF: Dept. of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544 United States
AU: Ho, D T
EM: david@ldeo.columbia.edu
AF: Now at Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964 United States
AU: Simonds, C
EM: csimonds@adamsharkness.com
AF: Bowdoin College, Dept. of Physics and Astronomy 8800 College Station, Brunswick, ME 04011 United States
AU: Simonds, C
EM: csimonds@adamsharkness.com
AF: Now at Adams Harkness, 99 High Street, Boston, MA 02110 United States
AU: Mika, R
EM: rmika@princeton.edu
AF: Dept. of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544 United States
AB: Measurements of atmospheric $O_2$ and $CO_2$ can be combined to create a ``tracer'' referred to as Atmospheric Potential Oxygen (APO) [Stephens {\em et al.} 1998]. APO (defined as $O_2 + 1.1 \times CO_2$) is unaltered by terrestrial photosynthesis and respiration, and influenced only slightly by fossil fuel combustion. Consequently, measurements of $O_2$ and $CO_2$ have the potential to provide unique constraints on models of oceanic circulation and biology, and air-sea gas exchange. We present a 7-year record of $O_2$ and $CO_2$ measurements, combining data from the Princeton University and Scripps Institute of Oceanography $O_2$ flask-sampling networks. These values include both regular land-based observations and shipboard samples collected in the tropical Pacific. We find that the annually averaged North-South gradient in APO exhibits the gross features we expect from the combined influences of ocean processes, fossil fuel combustion and atmospheric transport: an interhemispheric gradient that is slightly higher in the South. Furthermore, the data show a substantial APO peak in the tropics (the so-called ``equatorial bulge'') resulting from large fluxes of both $O_2$ and $CO_2$ from the ocean to the atmosphere due to equatorial upwelling. We then use inversely estimated fluxes of $O_2$ and $N_2$ [Gruber {\em et al.}, 2001, Gloor {\em et al.}, 2001] along with observationally based $CO_2$ fluxes [Takahashi {\em et al.}, 1999] and the TM3 model of atmospheric transport to predict APO values at the locations of our observations. In contrast to earlier work [Stephens {\em et al.}, 1998, Gruber {\em et al.}, 2001], we find that the model generally agrees well with the data, reproducing the pole-to-pole gradient within a few per meg. Furthermore, the observed equatorial bulge is actually somewhat larger than predicted by the model. We find that our comparison metric for APO data-model agreement is particularly sensitive to the choice of atmospheric transport model.
DE: 4808 Chemical tracers
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting