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