AEROSOL PHYSICOCHEMISTRY:
P3 AIRCRAFT MEASUREMENTS FOR TRACE-P
[University of Hawaii, Honolulu, Hawaii]
P.I. Antony
D. Clarke; 808-956-6215; tclarke@soest.hawaii.edu
Co P.I. Vladimir
Kapustin; 808-956-7777; kapustin@soest.hawaii.edu
We propose a suite
of aerosol physio-chemical and optical measurements aboard the
NASA P-3 aircraft during TRACE-P designed to provide fundamental
information on their influence on air mass properties emerging
from the Asian Continent. Deliberate efforts will be made to link aerosol size, mass,
volatile composition and surface area to variations in gas phase
species associated with combustion sources, natural sources (eg.
dust) and unperturbed air masses. We will identify variations in
aerosol microphysics/ composition/optical properties and the related
structure of aerosol fields. The comparison of our measured in-situ
properties to remotely sensed (satellite) and modeled aerosol properties
during TRACE-P will also provide a foundation for interpreting
satellite and model data over spatial and temporal scales beyond
those characterized during TRACE-P. Combined
with the TRACE-P flight strategy we expect this to allow estimates
of fluxes of aerosol and gas phase constituents leaving the Asian
continent during TRACE-P and their link to gas phase species.
Our aerosol measurement
system is able to characterize aerosol concentrations and properties
over all size ranges of primary interest to processes in atmospheric
chemistry and aerosol physics (ie. 0.003 to 20 μm). These
include processes ranging from aerosol nucleation and evolution
of the size distribution to mass burdens and aerosol radiative
effects. A combination
of instruments is necessary since this represents a factor of 2000
in diameter and ten+ orders of magnitude in particle mass. Size-distributions
will be established with a combination of laser optical particle
spectrometer, aerodynamic particle sizer (APS), forward scattering
spectrometer probe (FSSP), a radial differential mobility analyzer
(RDMA) and several condensation nuclei counters. Thermal
analysis (volatility) of size distributions allow inference of
aerosol physicochemistry and can distinguish air masses and aerosol
with continental vs. "clean" characteristics. This will
also provide the state of mixing of aerosol components including
soot, dust, sea-salt, sulfates etc. needed for isolating their
contribution to aerosol properties. A
forward scattering spectrometer probe (FSSP) and Gerber probe will
also be used to size larger ambient particles including cloud water
droplets (will yield liquid water content).
Continuous nephelometer
measurements of total and submicrometer scattering coefficients
(their difference identifies coarse dust contributions to total)
will help link aerosol microphysics to size resolved chemical and
optical properties. This will enable direct comparison to satellite
products (radiance, optical depth) and model products (mass concentrations
of dust, soot, sulfate etc, optical depth). In
this way, satellite (AVHRR, SeaWiFS) and chemical transport model products
can be used to extend TRACEP observations, using observed relationships,
over greater temporal and spatial scales.
Final data will reside
in the TRACE-P archive and value-added data products will appear
on our HiGEAR website (Hawaii Group for Environmental Aerosol Research)
[http://pali.soest.hawaii.edu/].
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