Sun Photometer Measurements
Sun photometers are used to measure aerosol optical depths to
measure the column aerosol optical loading. A sun photometers consists
of a narrow field of view sensor which is pointed at the sun.
Following Beers Law one can write I = Io exp(tau/air mass). Here
tau is the sum of the aerosol and molecular optical depths. The
air mass is one over the cosine of the solar zenith angle and varies
from 1 when the sun is directly overhead to 20 or more when the sun is
on the horizon. I and Io are the solar direct beam at the top and
bottom of the atmosphere. As the aerosol loading increases, more light
is scattered out of the direct solar beam and the sun photometer
measurement decreases. While many sun photometers are hand held, the
more expensive systems are automated and point to the sun
automatically.
Ship Based Sun Photometer Measurements (Microtops Hand Held)
Aircraft Based Sun Photometer Measurements (Microtops Hand Held)
Automated Sun Photometer Measurements (New Work In Progress)
Collaboration With Hawaii West Exploratory Academy