 |
| Titel |
Ozone and NOx chemistry in the eastern US: evaluation of CMAQ/CB05 with satellite (OMI) data |
| VerfasserIn |
T. P. Canty, L. Hembeck, T. P. Vinciguerra, D. C. Anderson, D. L. Goldberg, S. F. Carpenter, D. J. Allen, C. P. Loughner, R. J. Salawitch, R. R. Dickerson |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 19 ; Nr. 15, no. 19 (2015-10-02), S.10965-10982 |
| Datensatznummer |
250120071
|
| Publikation (Nr.) |
 copernicus.org/acp-15-10965-2015.pdf |
|
|
|
|
|
| Zusammenfassung |
| Regulatory air quality models, such as the Community Multiscale Air Quality model (CMAQ), are used by federal and state agencies
to guide policy decisions that determine how to best achieve adherence with National Ambient Air Quality Standards for surface
ozone. We use observations of ozone and its important precursor NO2 to test the representation of the photochemistry and
emission of ozone precursors within CMAQ. Observations of tropospheric column NO2 from the Ozone Monitoring Instrument
(OMI), retrieved by two independent groups, show that the model overestimates urban NO2 and underestimates rural
NO2 under all conditions examined for July and August 2011 in the US Northeast. The overestimate of the urban to rural
ratio of tropospheric column NO2 for this baseline run of CMAQ (CB05 mechanism, mobile NOx emissions from the
National Emissions Inventory; isoprene emissions from MEGAN v2.04) suggests this model may underestimate the importance of
interstate transport of NOx. This CMAQ simulation leads to a considerable overestimate of the 2-month average of 8 h
daily maximum surface ozone in the US Northeast, as well as an overestimate of 8 h ozone at AQS sites during days when the
state of Maryland experienced NAAQS exceedances. We have implemented three changes within CMAQ motivated by OMI NO2 as
well as aircraft observations obtained in July 2011 during the NASA DISCOVER-AQ campaign: (a) the modeled lifetime of organic
nitrates within CB05 has been reduced by a factor of 10, (b) emissions of NOx from mobile sources has been reduced by
a factor of 2, and (c) isoprene emissions have been reduced by using MEGAN v2.10 rather than v2.04. Compared to the baseline
simulation, the CMAQ run using all three of these changes leads to considerably better simulation of column NO2 in
both urban and rural areas, better agreement with the 2-month average of daily 8 h maximum ozone in the US Northeast, fewer
number of false positives of an ozone exceedance throughout the domain, as well as an unbiased simulation of surface ozone at
ground-based AQS sites in Maryland that experienced an ozone exceedance during July and August 2007. These modifications to CMAQ
may provide a framework for use in studies focused on achieving future adherence to specific air quality standards for surface
ozone by reducing emission of NOx from various anthropogenic sectors. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|