Aerosol optical thickness in conjunction with an atmospheric model can provide estimates of atmospheric effects on transmitted and reflected solar radiation. These effects can then be used to correct aircraft and satellite radiometric data. In FIFE, three sunphotometers were used to track the sun through a range of airmasses during the period of February 6, 1987 through October 31, 1989. The Aerosol Optical Thickness from GSFC Data Set were analyzed using the Langley technique. Rayleigh optical depth was subtracted, and aerosol, ozone, and water vapor abundance's simultaneously measured. In retrieving ozone a Junge aerosol model was assumed, thus the natural log of aerosol optical depth was linear with wavelength (Bruegge et al. 1992). This approach allows measurement of aerosol, but is limited by the accuracy of the ozone data.