 |
| Titel |
Optimizing global CO emission estimates using a four-dimensional variational data assimilation system and surface network observations |
| VerfasserIn |
P. B. Hooghiemstra, M. C. Krol, J. F. Meirink, P. Bergamaschi, G. R. Werf, P. C. Novelli, I. Aben, T. Röckmann |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 10 ; Nr. 11, no. 10 (2011-05-20), S.4705-4723 |
| Datensatznummer |
250009750
|
| Publikation (Nr.) |
 copernicus.org/acp-11-4705-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| We apply a four-dimensional variational (4D-VAR) data assimilation system to
optimize carbon monoxide (CO) emissions for 2003 and 2004 and to reduce the
uncertainty of emission estimates from individual sources using the chemistry
transport model TM5. The system is designed to assimilate large (satellite)
datasets, but in the current study only a limited amount of surface network
observations from the National Oceanic and Atmospheric Administration Earth
System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) is
used to test the 4D-VAR system. By design, the system is capable to adjust
the emissions in such a way that the posterior simulation reproduces
background CO mixing ratios and large-scale pollution events at background
stations. Uncertainty reduction up to 60 % in yearly emissions is observed
over well-constrained regions and the inferred emissions compare well with
recent studies for 2004. However, with the limited amount of data from the
surface network, the system becomes data sparse resulting in a large solution
space. Sensitivity studies have shown that model uncertainties (e.g.,
vertical distribution of biomass burning emissions and the OH field) and the
prior inventories used, influence the inferred emission estimates. Also,
since the observations only constrain total CO emissions, the 4D-VAR system
has difficulties in separating anthropogenic and biogenic sources in
particular. The inferred emissions are validated with NOAA aircraft data over
North America and the agreement is significantly improved from the prior to
posterior simulation. Validation with the Measurements Of Pollution In The
Troposphere (MOPITT) instrument version 4 (V4) shows a slight improved
agreement over the well-constrained Northern Hemisphere and in the tropics
(except for the African continent). However, the model simulation with
posterior emissions underestimates MOPITT CO total columns on the remote
Southern Hemisphere (SH) by about 10 %. This is caused by a reduction in SH
CO sources mainly due to surface stations on the high southern latitudes. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|