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/].