CALIBRATION

The Microtops instruments are calibrated at the NASA Goddard Space Flight Center (GSFC) calibration facility via a transfer calibration procedure between the Microtops and the master Cimel sun photometer at GSFC, which has a calibration traceable to a Langley calibration of a Cimel sun photometer on Mauna Loa, Hawaii. In general, the estimated uncertainty of the aerosol optical depth in each channel does not exceed plus or minus 0.02, which is slightly higher than the uncertainty of AERONET field (not master) instruments.

PROCESSING

Once the instrument has returned from deployment, a post-field calibration is performed to determine the change in the measurement sensitivity of the instrument. Calibration coefficients are assumed to change linearly during the deployment period between the pre-field and post-field calibration values. These interpolated calibration values are applied to the field data and processed using the AERONET Version 2 algorithm.

INSTRUMENTATION

Measurement	Image	Manufacturer Information
Microtops II Spectral range: 340 to 1020 nm [info sheet]		Solar Light Company, Inc. (USA) 100 East Glenside Ave. Glenside, PA 19038 USA Phone: 215.517.8700 Fax: 215.517.8747 http://www.solar.com/index.htm
Garman GPSMap 60CSx		GARMIN International, Inc (USA) 1200 E. 151st Street Olathe, KS 66062-3426 USA Phone: 913.397.8200 Fax: 913.397.8282 http://garmin.com Garmin (Europe) Ltd. http://garmin.co.uk Garmin (Asia) Corporation http://garmin.com.tw