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| Titel |
Global chemical regimes for ozone formation in a global on-line chemical weather prediction model (NMMB/BSC-CHEM) |
| VerfasserIn |
Pedro Jiménez-Guerrero, Oriol Jorba, Alba Badia |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056587
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| Zusammenfassung |
| Ozone (O3) production in global chemical models is still an important issue, since O3
chemistry is inherently nonlinear. Moreover, the kinetics of ozone chemistry and its two
main precursors, nitrogen oxides (NOx) and volatile organic compounds (VOC)
represents an important field of uncertainty in atmospheric chemistry. Despite a number
of works have been developed trying to evaluate the chemicals regimes of ozone
formation by using several indicators based on model species, it is still unclear
whether the indicator ratios would show similar behaviour for a wide variety of
conditions.
In this study we examine the sensitivity of summertime ozone for the year 2004, its
precursors, and its production by running a recently developed on-line chemical weather
prediction model at a reasonably high resolution (1x1 degree). The model used,
NMMB/BSC-CHEM, is a new fully on-line chemical weather prediction system for meso to
global scale applications currently under development at Barcelona Supercomputing
Center. The atmospheric driver is the NCEP/NMMB numerical weather prediction
model developed at National Centers for Environmental Prediction (NCEP). A
gas-phase chemical mechanism has been coupled online with NCEP/NMMB. The
chemical mechanism implemented is CB05 coupled with Fast-J photolysis scheme.
The dry deposition scheme follows the deposition velocity analogy for gases, and
scavenging, mixing and wet deposition for grid-clouds and sub-grid clouds are
also considered. The biogenic emissions are computed with the online MEGAN
model. The POET emission inventory provides the anthropogenic emissions for the
simulations.
Diverse photochemical species derived from the air quality model were used as indicators
in order to establish the chemical sensitivity regime existing in different regions of the world.
These indicadors include NOy, NOz, and O3/NOy and O3/NOz ratios. Variations in indicator
behavior are analytically linked to variations in the O3 production efficiency per primary
radical production. H2O2- and HNO3- derived indicators (e.g. H2O2/HNO3, H2O2/NOy or
H2O2/NOz ratios) were also used, albeit they entail higher uncertainties for differencing
recent and aged ozone. Finally, the photochemical age (PA) also performed as a good
indicator to establish ozone chemical regimes since PA is a useful overall measure of where
an air mass is in the aging continuum between fresh NOx emissions at one end (lowest PA
values under 0.2 found for Africa, South America and some emitting areas over
populated areas of Europe, North America and Asia), and a depleted background-like
condition at the other end (values over 0.8 for remote areas from fresh emissions). |
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