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The University of Denver’s Aerosol Research Group has
collected aerosol measurements from aircraft platforms in both the
stratosphere and the troposphere. These data are analyzed to help
answer questions about the chemical and physical properties of the
atmosphere. Examples of such data analysis include:
Determination of Aerosol Extinction:
Aerosol concentration and
size distribution data collected with the DU instruments are used to
determine total aerosol surface area in the stratosphere. MIE Theory
calculations are applied to the surface area measurements to determine
aerosol extinction coefficients.
Satellites are currently
applied to measure aerosol extinction in the atmosphere. Aerosol
surface areas are derived from the data collected by these satellites.
The DU aerosol surface area data and calculated aerosol extinctions are
used to validate the information estimated from satellites.
Evaluation Chemistry of Rocket Plumes in the
Stratosphere:
The DU aerosol group has
collected aerosol concentration and size distribution data in several
missions during which rocket plumes have been encountered. The data
collected in these plumes are used to assess the dynamics and chemistry of
rocket emissions in the stratosphere. From the aerosol chemical,
size and concentration data collected, the rate of particle growth and
dispersion in the plumes may be predicted, and the extent of heterogeneous
chemistry can be estimated using the measurements and photochemical
models.
Understanding Heterogeneous Carbon Chemistry in
the Stratosphere:
During a 1997 test flight
for the POLARIS expedition off the California coast, an extraordinary
plume of elevated condensation nuclei (CN) concentration was encountered
in the lower stratosphere. The source of these particles is
estimated to be a liquid-fueled rocket launched in central Asia 12 days
prior to the encounter. Relatively strong correlations between the
concentration of the CN with the concentrations of NO were observed in the
plume. Photochemical models have been applied to explain the
chemistry in the plume. Although many uncertainties about the chemistry of
the plume exist, modeling results suggest that heterogeneous carbon
chemistry had been occurring in the plume.
Evaluation of Particle Growth in Power Plant
Plumes:
The DU group, with NOAA
Aeronomy Laboratory, has collected data in the southern United States,
specifically through urban and power plant plumes. With aerosol
concentration and size distribution data, the rate of particle formation
in these plumes. Eventually, these data will be used to help
determine the parameters that affect particle growth in the troposphere.
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