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. The system is specifically designed to provide uninterrupted
monitoring of momentum, heat, water vapor, and carbon dioxide fluxes. Walker
Branch watershed flux studies have recently been extended in an exploration of
the flux contributions of the forest floor and the trees themselves. Experience
gained in this effort will be important for anticipated surface-layer model
testing and evaluation studies (under NOAA/GEWEX/GCIP). At Research Triangle
Park, and in cooperation with Oak Ridge, a separate portable flux-measuring
system was developed, this time designed for direct measurement of trace gas
fluxes but relying on measurement of the standard micrometeorological quantities
for quality assurance. The system provides for direct eddy correlation
measurements of sulfur dioxide, ozone, and carbon dioxide fluxes, and of nitric
acid by filter pack gradient analysis, as well as the important components of
the surface energy budget. The Mobile Flux Platform, and GPS. Ron Dobosy (dobosy@atdd.noaa.gov)
During 1994, the use of new Global Positioning System (GPS) technology was
evaluated, and the newest available GPS systems were adopted. The systems
developed for aircraft eddy flux use have now been fitted to one of NOAA's two
Twin Otter aircraft. Large-Area Exchange Tim Crawford (crawford@atdd.noaa.gov)
The Oak Ridge group has frequently deployed both tower and aircraft eddy
correlation systems during studies of areal fluxes over a heterogenous surfaces,
in real-world studies of how well flat-earth formulations apply in real
situations. Analysis of tower eddy correlation fluxes of heat and moisture
displayed differences in the fluxes among alfalfa, corn, and wheat crops; during
daytime, transpiration rates differed by 20% to 50%. Measurements of momentum,
heat, and moisture fluxes from the ATDD Long-EZ research airplane were analyzed
to quantify spatial variabilities in the fluxes. Carbon Dioxide. Tilden Meyers (meyers@atdd.noaa.gov)
Continuous eddy correlation measurement of CO2 flux over the Walker Branch (Oak
Ridge) forest have continued since 1993. The eddy flux measurement of CO2
exchange is now a mature technology. (See discussion above -- "Tower
Studies".) Air-surface exchange has been studied extensively in classical
investigations that focus on revealing the processes involved. Winston Luke (winston.luke@noaa.gov)
The importance of accurate air-surface flux formulation in numerical models is
now widely acknowledged. Atmospheric Loadings to Coastal Ecosystems Regulatory
strategies that fail to recognize that part of the problem arises from
atmospheric deposition will not work as expected. The ARL Role Measurement and
modeling of atmospheric deposition are long-standing ARL specialties. east
coast, from Maine to Florida. ARL is leading a large part of the integrated
research effort focusing on this issue. Leadership of the Chesapeake Bay Air
Subcommittee Contact -- richard.valigura@noaa.gov The Chesapeake Bay Program (CBP)
is a multi-agency program of targeted scientific research and integrated
assessment, which has been instrumental in alerting policy makers to the need to
couple air and water issues in their decision-making processes. Characterizing
the East and Gulf Coast Atmospheric Resource Contact -- bruce.hicks@noaa.gov It
is clear that emissions from the "airshed" that serves as a regional
origin of air pollutants affecting the Chesapeake Bay also influence other
coastal ecosystems. east coast estuarine and coastal ecosystems would benefit as
well. Research Grade Monitoring of Deposition in the Coastal Zone Contact --
richard.artz@noaa.gov The atmospheric deposition that affects east coast
ecosystems is very poorly measured. For dry deposition, there are very few data
points. The NOAA Atmospheric Integrated Research Monitoring Network (AIRMoN) has
constituted a framework for exploring methods for quantifying the actual
deposition loadings to the Chesapeake Bay watershed. ARL is currently operating
several AIRMoN stations in the watershed -- State College, PA, is a long-term
site where both wet and dry deposition are being studied. Modeling Deposition to
the Coastal Zone at Regional Scales Contact -- rdennis@hpcc.epa.gov The Regional
Acid Deposition Model (RADM) has been adopted as the modeling workhorse of the
east coast estuarine regulatory community. The results indicate that grid sizes
*2 km may be necessary to resolve the effects of the Bay on atmospheric dry
deposition (but not wet). Estimating Air-Water Exchange of Nitric Acid in
Coastal Areas Contact -- richard.valigura@noaa.gov A project was successfully
undertaken which, i) developed and evaluated an iterative bulk exchange model to
estimate air-water exchange of heat, water and momentum from buoy data, and ii)
used the model outputs to estimate air-water transfer rates of nitric acid
(HNO3). Natural emissions of Oxidant precursors: Validation of techniques and
Assessment (NOVA) Contact -- winston.luke@noaa.gov Historically, NOx emissions
from soils have been estimated using chamber, or enclosure, techniques, whereby
the measured rate of increase of [NO] within the chamber used to derive an
estimate of the NO emission flux from the underlying soil surface. Mercury
Deposition Contact -- meyers@atdd.noaa.gov ARL researchers at Oak Ridge (a
collaboration between ATDD and Oak Ridge National Laboratory) have been working
on techniques to measure the deposition of mercury directly. More recently,
field studies have been conducted in southern Florida, where mercury originating
from sugar farming practices is suspected to be affecting coastal ecosystem
viability. Research Plans Linkages within NOAA The ARL coastal studies program
is strongly linked with the NOAA Chesapeake Bay Office of the National Marine
Fisheries Service. The work is also tied to the NOAA Coastal Ocean Program, and
to coastal activities of the National Ocean Service. The Chesapeake Bay Air
Subcommittee (led by ARL) serves as an interface with all federal agencies
involved in related research (EPA, DOD, DOE, DOI, DOA, NASA, Smithsonian) as
well as with the air and water environmental components of each of the states in
the Chesapeake Bay region (Delaware, New York, Pennsylvania, Maryland, Virginia,
District of Columbia, West Virginia). The NPS Air Resources Division synthesizes
information acquired through the NPS air quality research and monitoring
programs, disseminates the information to park personnel and managers, and works
with park personnel to develop air quality related interpretive goals, themes,
projects and activities. NPS interpretive programs serve to educate the park
visitor about air resource by: Describing statutory authorities which help the
NPS protect air resources. In 1983, barely a half dozen parks were using air
quality information in interpretive/educational programs.