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Air Quality & Dispersion Today, the air quality aspect of ARL research is by
far the dominant theme, but distinctions among the themes remain somewhat vague.
For example, the models developed for emergency response purposes are among
those used for air quality prediction. The Air Quality and Dispersion theme is
one of the strongest ties that binds ARL's components together. ARL is not
heavily involved in the pure science of the business. Instead, ARL focusses on
the need to assemble integrated understanding and models from all available
sources, to develop the capability to predict changes in air quality that will
follow changes in emissions, or that will occur as a result of meteorological
factors. ARL air quality research extends to studies of atmospheric deposition
essentially the coupling between the atmospheric pollutant environment and the
surface below.
ARL now operates the only research-grade deposition monitoring
network in the nation: AIRMoN (the Atmospheric Integrated Research Monitoring
Network). Programs. Air Quality and Deposition Modeling Air quality models have
demanded this kind of coupling for a considerable time. As a result, there are
now well-developed descriptions of PBL processes in use in air quality models.
ARL research products are now receiving a wider audience, within the mesoscale
modeling community at large. It is recognized that modern models are invariably
data assimilative, and that modern monitoring programs require coupled modeling
activities for data interpretation. Model development programs are supported by
a vigorous physical modeling program, located at Research Triangle Park, NC.
ARL
operates one of the nation's major fluid modeling facilities, at which studies
are conducted on the effects of mountains, buildings, and other surface
obstacles on atmospheric flow patterns. Integrated Monitoring, and AIRMoN The
Atmospheric Integrated Research Monitoring Network is an atmospheric component
to the overall national integrated monitoring initiative that is currently
evolving. AIRMoN has two principal components: wet and dry deposition. ARL
presently focuses its research attention on the measurement of precipitation
chemistry with fine time resolution (AIRMoN-wet), the development of systems
for measuring deposition, both wet and dry, the measurement of dry deposition
using micrometeorological methods (AIRMoN-dry), the development of techniques
for assessing air-surface exchange in areas (such as specific watersheds) where
intensive studies are not feasible, and the extension of local measurements
and knowledge to describe areal average exchange in numerical models. Aerosols
and visibility ARL specializes in the geochemical cycling of atmospheric
aerosols, particularly the particulate component.
Research groups in ARL
concentrate on (a) the injection of dust and soil particles into the atmosphere,
(b) the transport of particles through the atmosphere, © the production of
aerosol particles in the air by chemical reactions, (d) the scavenging of
airborne particles by clouds and their subsequent deposition in precipitation,
(e) the dry deposition of particles as air moves across different landscapes,
and (f) the assembly of numerical models. Specific topics include the
injection of dust and soil particles into the atmosphere, the long-range
transport of particles through the atmosphere, the production of aerosol
particles in the air by chemical reactions, the scavenging of airborne
particles by clouds and their subsequent deposition in precipitation, and the
dry deposition of particles as air moves across different landscapes.
International ARL serves as the leader of the U.S. multi-agency effort to impose
formalized and uniform quality assurance programs on the many national air
quality and deposition monitoring networks that are operational around the
globe. How are ozone concentrations calculated with Hysplit? Ozone is then
calculated from the photostationary state equation. The IER solution is used in
the operational Hysplit ozone calculation. The pollutant particles are tracked
and air concentrations for each species are computed each advection time step
following the usual lagrangian approaches. At the conclusion of the advection
step the GRS differential equations are solved on the concentration grid (Eulerian
solution), and the change of concentration of each pollutant species is applied
to the pollutant mass on the particles that contributed concentration to each
grid cell. -Eulerian chemistry solution on the grid dc/dt = {Equations 1 - 7} 1)
ROC + hv -* RP + ROC Nitric oxide-ozone titration reaction 5) RP + RP -* RP k5 =
10200 Sink for nitrogen dioxide to stable gaseous nitrates What is the
Integrated Empirical Rate Model? Time Integrated on the particle (Lagrangian):
Algebraic solution on the grid (Eulerian): Smog product = ozone produced and
oxidized nitric oxide Photostationary state balances formation and destruction
of ozone Definition of NOx Air-Surface Exchange Heat, Momentum, Water, and CO2
Transfer at the Earth Surface Presently, ARL focuses its attention on the
development of systems for measuring fluxes at specific locations, and the
extension of local measurements and understanding to describe areal average
exchange in numerical models. Improving NOAA's prediction capabilities requires
this understanding. ARL's internal model developments are arranged to be in
close association with the field work. Tower Studies. Dennis Baldocchi (baldocchi@atdd.noaa.gov)
Three ARL groups (Oak Ridge, Research Triangle Park, and Silver Spring) are
currently working with portable eddy flux systems, based upon original ARL
developments.
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