HR: 0800h
AN: A51C-0779    [Abstracts]
TI: Global Trends and Distributions of Atmospheric Nitrous Oxide
AU: * Elkins, J W
EM: james.w.elkins@noaa.gov
AF: NOAA/CMDL, 325 Broadway, Boulder, CO 80305-3328 United States
AU: Dutton, G S
EM: geoff.dutton@noaa.gov
AF: CIRES/CU, Campus Box 916, Boulder, CO 80309 United States
AU: Hall, B D
EM: bradley.hall@noaa.gov
AF: NOAA/CMDL, 325 Broadway, Boulder, CO 80305-3328 United States
AU: Butler, J H
EM: james.h.butler@noaa.gov
AF: NOAA/CMDL, 325 Broadway, Boulder, CO 80305-3328 United States
AU: Thompson, T M
EM: thayne.m.thompson@noaa.gov
AF: NOAA/CMDL, 325 Broadway, Boulder, CO 80305-3328 United States
AU: Mondeel, D J
EM: Debra.J.Mondeel@noaa.gov
AF: CIRES/CU, Campus Box 916, Boulder, CO 80309 United States
AU: Dlugokencky, E J
EM: ed.dlugokencky@noaa.gov
AF: NOAA/CMDL, 325 Broadway, Boulder, CO 80305-3328 United States
AB: Atmospheric nitrous oxide (N2O) is a trace gas (2003 global mean = 318 parts-per-billion (ppb)) that is involved in global warming and stratospheric ozone depletion. It is the major source of stratospheric nitric oxide (NO). Tropospheric and stratospheric measurements show that N2O contributes about 1600 Mtons of N2O as nitrogen (N) to the atmosphere. Observed tracer-tracer correlations in the stratosphere suggest that the lifetime of stratospheric N2O is about 125 years. As no other major sink has been identified, this sink represents a total estimated removal of N2O of 13 Mtons (N) per year. Many types of natural (land and water) and man-made sources for atmospheric N2O exist, but there is considerable uncertainty in the magnitudes of these sources. Previously published work has shown that the relative strength of the oceanic source to the natural land source is between 20 and 40%. The tropics appear to be a strong source region. Most studies scale the magnitudes of these sources against the better-known total atmospheric sink. Over the long-term, the atmospheric growth rate or trend of N2O has averaged about 0.75 ppb per year, or about 5 Mtons (N) per year. However, there is considerable year-to-year variability in the global trend, which ranges from 0.27 to 1.4 ppb per year since 1988 when high precision in situ measurements began at CMDL. The growth rate appears to be affected by El Ni¤o Southern Oscillation (ENSO) events. We will present both flask and in situ measurements from the NOAA/CMDL network to examine the uncertainties in the N2O budget. Comparisons of data with other networks including Advanced Global Atmospheric Gas Experiment (AGAGE) and the Carbon Cycle Greenhouse Gas (CCGG) of CMDL will be presented.
UR: http://www.cmdl.noaa.gov/hats
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution--urban and regional (0305)
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting