From: Chris Cantrell
Organization: NCAR
Research Area: MICROPHYSICS AND RADIATION
Mission Scenario:
Radiative Balance of Ultraviolet and Visible Radiation in the Presence
of Clouds and Aerosols
There have been several attempts to understand the scattering,
absorption and transmission of radiation from 400 to 5000 nm in the
presence of clouds and aerosols, including the so-called "anomalous"
cloud absorption. The problems in the past have been possibly linked
to the use of improper instrumentation for this purpose. A
high-altitude aircraft coupled with a low-altitude aircraft
identically instrumented with upward- and downward viewing
spectroradiometer instruments outfitted with flat-plate (irradiance)
and hemispherical (actinic flux) collectors could go a long way toward
solving this problem. Additional instrumentation to quantify the
cloud and aerosol microphysical properties would be beneficial. A few
basic chemical measurements are also necessary including ozone and
water vapor, since photon path length enhancements due to multiple
scattering may explain some of the phenomena and absorption of light
in these cases could be very important.
The two aircraft would flight in tandem one above the other, with the
lower aircraft flying just below a cloud desk or aerosol layer. The
upper aircraft would fly above and within the clouds or aerosols. The
measurements between the two aircraft would be linked through
side-by-side flights. If the two aircraft have greatly different
cruise speeds, then looping flight patterns of the faster aircraft may
be required. Flights on the "sides" of clouds will also be necessary
to construct a fully closed radiation budget. It is desirable to
perform these flights at a variety of solar zenith angles (from 0 to
near 90 degrees).
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