 |
| Titel |
Development and applications of newly-developed photochemical/dynamic ship-plume model |
| VerfasserIn |
Chul H. Song, Hyun S. Kim, Rea S. Park |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038317
|
|
|
|
|
|
| Zusammenfassung |
| A photochemical/dynamic ship-plume model, which can consider the ship-plume dynamics
and ship-plume chemistry, simultaneously, was developed to gain a better understanding of
atmospheric impact of ship emissions. The model performance was then evaluated
by a comparison with the observation data measured on a NOAA WP-3D flight
during the Intercontinental Transport and Chemical Transformation 2002 (ITCT
2K2) airborne field campaign. The simulation conditions and parameters, such
as meteorological conditions, emission rates, and background gas and particulate
species concentrations, were obtained directly and/or inferred indirectly from the
ITCT 2K2 observation data. The model-predicted concentrations showed good
agreement with the observed concentrations of five ambient species (NOx, NOy, ozone,
HNO3, and H2SO4) at the eight plume transects by the WP-3D flight with strong
correlations around the 1:1 line (0.64-¤R-¤0.85). In addition, a set of tests were
carried out to approximate the magnitude of the reaction probability of HNO3 onto
sea-salt particles in the model-observation comparison framework. These results
suggest that the reaction probability of HNO3 onto sea-salt particles may be in
the order of 0.05-0.1. The equivalent NOx lifetime throughout the “entire plume”
was also estimated from photochemical/dynamic ship-plume modeling. The NOx
lifetimes estimated throughout the entire ship plume ranged from 2.64 hrs to 3.76 hrs
under stable to neutral stability conditions. The short NOx lifetime over the entire
ship plume clearly shows that the ship-plume chemistry shortens the NOx lifetime
considerably. Moreover, numerical analysis was carried out to exam the detailed
sources (and/or source contributions) of the elevated levels of HCHO in the ship
corridors. From the multiple simulations, CH4 oxidation by elevated levels of OH
radicals is found to be mainly responsible for the elevated levels of HCHO in the ship
corridors. More than ~90% of HCHO within the entire ship plumes is produced by this
atmospheric chemical process, except for very near the ship stacks where the main
source of the elevated HCHO levels would be primary HCHO from ships (due to
deactivation of CH4 oxidation from the depletion of OH radicals). Therefore, the
ship-plume chemistry model should be used to model the changes in ship-plume chemical
compositions and better evaluate the atmospheric impact of ocean-going ship emissions. |
|
|
|
|
|
|