Global and regional emissions estimates for N<sub>2</sub>O
We present a comprehensive estimate of nitrous oxide (N<sub>2</sub>O) emissions using observations and models from 1995 to 2008. High-frequency records of tropospheric N<sub>2</sub>O are available from measurements at Cape Grim, Tasmania; Cape Matatula, American Samoa; Ragged...
| Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2014-05-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/14/4617/2014/acp-14-4617-2014.pdf |
| Summary: | We present a comprehensive estimate of nitrous oxide (N<sub>2</sub>O) emissions using
observations and models from 1995 to 2008. High-frequency records of
tropospheric N<sub>2</sub>O are available from measurements at Cape Grim, Tasmania;
Cape Matatula, American Samoa; Ragged Point, Barbados; Mace Head, Ireland;
and at Trinidad Head, California using the Advanced Global Atmospheric Gases
Experiment (AGAGE) instrumentation and calibrations. The Global Monitoring
Division of the National Oceanic and Atmospheric Administration/Earth System
Research Laboratory (NOAA/ESRL) has also collected discrete air samples in
flasks and in situ measurements from remote sites across the globe and
analyzed them for a suite of species including N<sub>2</sub>O. In addition to these
major networks, we include in situ and aircraft measurements from the
National Institute of Environmental Studies (NIES) and flask measurements
from the Tohoku University and Commonwealth Scientific and
Industrial Research Organization (CSIRO) networks. All measurements show
increasing atmospheric mole fractions of N<sub>2</sub>O, with a varying growth rate
of 0.1–0.7% per year, resulting in a 7.4% increase in the background
atmospheric mole fraction between 1979 and 2011. Using existing emission
inventories as well as bottom-up process modeling results, we first create
globally gridded a priori N<sub>2</sub>O emissions over the 37 years since 1975. We
then use the three-dimensional chemical transport model, Model for Ozone and
Related Chemical Tracers version 4 (MOZART v4), and a Bayesian inverse method
to estimate global as well as regional annual emissions for five source
sectors from 13 regions in the world. This is the first time that all of
these measurements from multiple networks have been combined to determine
emissions. Our inversion indicates that global and regional N<sub>2</sub>O emissions
have an increasing trend between 1995 and 2008. Despite large uncertainties,
a significant increase is seen from the Asian agricultural sector in recent
years, most likely due to an increase in the use of nitrogenous fertilizers,
as has been suggested by previous studies. |
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| ISSN: | 1680-7316 1680-7324 |