Instruments for measuring Aerosol Optical Thickness
Students point a sun photometer at the sun, measure at the red and green and always record the largest voltage reading they obtain on a digital voltmeter connected to the photometer. Pointing to the sun is done manually. The values of AOT will be calculated automatically when entering data through GLOBE data entry page.
Order GLOBE sunphotometer from David Brooks, Institute for Earth Science Research and Education.
The measurement principle is to point the sun and search for the maximum flow. The photometer keeps only the maximum measured and then calculated the optical thickness.
The sun alignment is done manually. It is facilitated by the sighting device located above the display. The calculation of optical depth (detailed in the user manual) use the raw brightness measurements,calibration coefficients, date and the GPS position as well as atmospheric pressure.
For instructions how to use Calitoo sun photometer, download the Users Manual.
Learn more about the device on Calitoo.com website.
See the process of sunphotometer calibration that took place at Canary Islands: