Aerosol optical depth analysis with NOAA GOES and POES in the Western Atlantic

• Main Author: Kuciauskas, Arunas P.
• Other Authors: Durkee, Philip A.
• Published: Monterey California. Naval Postgraduate School 2012
• Online Access: http://hdl.handle.net/10945/5886

Approved for public release; distribution is unlimited. === An aerosol optical depth retrieval algorithm in the visible wavelengths for the NOAA POES AVHRR and GOES -8 visible imager is presented for the cloud free, marine atmosphere. The algorithm combines linearized single-scatter theory with an estimate of surface reflectance. Phase functions are parameterized using an aerosol size distribution model and the ratio of radiance values measured in channels 1 and 2 of the AVHRR. Retrieved satellite aerosol optical depth (AOD) is compared to three land-based sun photometer stations located on islands in the western Atlantic during July and September, 2001. GOES-8 channel 1 (visible wavelength) radiance values were initially calibrated using techniques developed by Rao. Additional corrections to the channel 1 GOES-8 radiances were made by applying a linear offset factor obtained during the experimental time period through comparison with AVHRR radiances. The results for the GOES -derived AOD compare favorably to the AERONET-measured AOD values. For both NOAA and GOES data, the comparison dataset has a correlation coefficient of 0.67 with a standard error of 0.07. For higher AOD cases (d = 0.25), the general trend was for the satellite-derived AOD values to underestimate AERONET-observed conditions. During these higher conditions, the scattering phase function pattern contained within the algorithm deviated from the expected pattern, especially between 140o - 180o. Overall, the more accurate calculations of AOD occurred over scatter angles between 140o - 150o and 170o - 180o.