 |
| Titel |
Worldwide biogenic soil NOx emissions inferred from OMI NO2 observations |
| VerfasserIn |
G. C. M. Vinken, K. F. Boersma, J. D. Maasakkers, M. Adon, R. V. Martin |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 18 ; Nr. 14, no. 18 (2014-09-30), S.10363-10381 |
| Datensatznummer |
250119073
|
| Publikation (Nr.) |
 copernicus.org/acp-14-10363-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Biogenic NOx emissions from soils are a large natural source
with substantial uncertainties in global bottom-up estimates
(ranging from 4 to 15 Tg N yr−1). We reduce this range
in emission estimates, and present a top-down soil NOx
emission inventory for 2005 based on retrieved tropospheric
NO2 columns from the Ozone Monitoring Instrument (OMI). We
use a state-of-science soil NOx emission inventory
(Hudman et al., 2012) as a priori in the GEOS-Chem chemistry transport
model to identify 11 regions where tropospheric NO2 columns
are dominated by soil NOx emissions. Strong correlations
between soil NOx emissions and simulated NO2 columns
indicate that spatial patterns in simulated NO2 columns in
these regions indeed reflect the underlying soil NOx
emissions. Subsequently, we use a mass-balance approach to
constrain emissions for these 11 regions on all major continents
using OMI observed and GEOS-Chem simulated tropospheric NO2
columns. We find that responses of simulated NO2 columns to
changing NOx emissions are suppressed over low NOx
regions, and account for these non-linearities in our inversion
approach. In general, our approach suggests that emissions need to
be increased in most regions. Our OMI top-down soil NOx
inventory amounts to 10.0 Tg N for 2005 when only
constraining the 11 regions, and 12.9 Tg N when
extrapolating the constraints globally. Substantial regional
differences exist (ranging from −40% to +90%), and
globally our top-down inventory is 4–35% higher than the
GEOS-Chem a priori (9.6 Tg N yr−1). We evaluate
NO2 concentrations simulated with our new OMI top-down
inventory against surface NO2 measurements from monitoring
stations in Africa, the USA and Europe. Although this comparison
is complicated by several factors, we find an encouraging improved
agreement when using the OMI top-down inventory compared to using
the a priori inventory. To our knowledge, this study provides, for
the first time, specific constraints on soil NOx emissions
on all major continents using OMI NO2 columns. Our results
rule out the low end of reported soil NOx emission
estimates, and suggest that global emissions are most likely around
12.9 ± 3.9 Tg N yr−1. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|