Atmospheric emissions and trends of nitrous oxide deduced from 10 years of ALE–GAGE data

Abstract

We present and interpret long‐term measurements of the chemically and radiatively important trace gas nitrous oxide (N2O) obtained during the Atmospheric Lifetime Experiment (ALE) and its successor the Global Atmospheric Gases Experiment (GAGE). The ALE/GAGE data for N2O comprise over 110,000 individual calibrated real‐time air analyses carried out over a 10‐year (July 1978–June 1988) time period. These measurements indicate that the average concentration in the northern hemisphere is persistently 0.75±0.16 ppbv higher than in the southern hemisphere and that the global average linear trend in N2O lies in the range from 0.25 to 0.31% yr−1, with the latter result contingent on certain assumptions about the long‐term stability of the calibration gases used in the experiment. Interpretation of the data, using inverse theory and a 9‐box (grid) model of the global atmosphere, indicates that the N2O surface emissions into the 90°N–30°N, 30°N–0°, 0°–30°S, and 30°S–90°S semihemispheres account for about 22–34, 32–39, 20–29 and 11–15% of the global total emissions, respectively. The measured trends and latitudinal distributions are consistent with the hypothesis that stratospheric photodissociation is the major atmospheric sink for N2O, but they do not support the hypothesis that the temporal N2O increase is caused solely by increases in anthropogenic N2O emissions associated with fossil fuel combustion. Instead, the cause for the N2O trend appears to be a combination of a growing tropical source (probably resulting from tropical land disturbance) and a growing northern mid‐latitude source (probably resulting from a combination of fertilizer use and fossil fuel combustion). The exact combination of these sources which best fits the data depends on the assumed tropospheric‐stratospheric exchange rates for N2O in the northern hemisphere relative to the southern hemisphere. Accepting a theoretically‐calculated N2O lifetime of 166±16 years due to stratospheric destruction only, we deduce from the ALE/GAGE data a 10‐year average global N2O emission rate of (20.5±2.4) × 1012 g N2O yr−1, but with significant year‐to‐year variations in emissions associated perhaps with year‐to‐year variations in tropical land disturbance.

Emissions, Concentrations, & Temperature: A Time Series Analysis

“…Endogenous Variables Identities ECO 2 Anthropogenic carbon emissions (Houghton and Hackler, 1999;Marland and Rotty, 1984) GLOBL Global Surface Temperature (Nicholls et al, 1994;Parker et al, 1998) RF (prefix) Radiative Forcing CO 2 , CH 9 , CFC 11 , CFC 12 , N 2 O (Shine et al, 1991;Kattenberg et al, 1996) ECH 4 Anthropogenic methane emissions (Kaufmann and Stern, 1996) CO 2 Atmospheric concentrations (Keeling and Whorf, 1994;Etheridge et al, 1996;) SOX (Wigley and Raper, 1992) CFC Atmospheric concentration of CFC's (Prather et al, 1987;Elkins et al, 1994) CH 4 Atmospheric concentrations (Etheridge et al, 1994;Khalil and Rasmussen, 1994;Dlugokenchy et al, 1994) N 2 O Atmospheric concentration of N 2 O (Prinn et al, 1990(Prinn et al, , 1995Machida et al, 1995) SOX Anthropogenic sulfur emissions (ASL, 1997) SUN Solar irradiance (Lean et al, 1995) SOI Southern Oscillation Index (Allen et al, 1991) NAO Northern Atlantic Oscillation Index (Hurrel, 1995) RFSS Radiative forcing of stratospheric sulfates in the northern hemisphere (appendix N) or southern hemisphere (appendix S) and latitude (appendix) (Sato et al, 1993) their atmospheric concentrations contain a stochastic trend. Traditionally, analyses of the temperature record avoid the assumption of stochastic trends because these trends are characterized by their long-term memory -the effects of innovations do not fade over time.…”

Atmospheric constraints on 2004 emissions of methane and nitrous oxide in North America from atmospheric measurements and a receptor-oriented modeling framework

“…Many global-scale studies have investigated emissions of methane and nitrous oxide (Prinn et al 1990;Chen and Prinn 2006;Hirsch et al 2006;Houweling et al 2006;Bergamaschi et al 2007;Nevison et al 2007;Huang et al 2008). These studies help immensely to improve understanding of emissions at large spatial and temporal scales (continental and annual).…”

Nitric and nitrous oxide emissions following fertilizer application to agricultural soil: Biotic and abiotic mechanisms and kinetics

“…The release of NO from agricultural soil can also result in losses of 5-10% of applied fertilizer nitrogen (N) [Shepherd et al, 1991;Veldkamp and Keller, 1997a, b]. Nitrous oxide (N20) accounts for an estimated 5 % of the total anthropogenic greenhouse effect [Rodhe, 1990] and is increasing in the atmosphere at about 0.25 % yr -1 [Prinn et al, 1990]. The oxidation of N20 to NO in the stratosphere promotes 03 destruction [Crutzen, 1981].…”