Exploring methods for routine atmospheric corrections for the red, near-infrared, and thermal bands of NOAA-14 AVHRR images

Includes bibliographical references (pages [74]-77)Radiances sensed by radiometers boarded on satellites are altered by transmitting through the atmosphere. Accurate correction for atmospheric degradation is currently based on modeling the physical behavior o f radiation as it passes through the atmosphere. An important limitation for the physical model is the requirement for detailed meteorological information pertaining to atmospheric humidity and the concentrations of atmospheric particles. Such data may be difficult to obtain in the necessary detail and may apply only to a few points during intensive field experiments. Routine application o f such a model is not now practicable. The objective o f this research is to develop (1 ) a simplified approach for atmospheric corrections for reflectances by using the unique spectral signature of the clear water pixel in satellite images and (2) a simplified method for retrieving land surface temperature from satellite radiances at the thermal bands. Under various clear-sky conditions, a radiative transfer model is used to generate the functional relationships between the atmospheric radiation properties such as scattering coefficient and the radiation caused by the atmosphere above the water body. The parameters, which are used to compute surface radiances, are evaluated with water vapor density and surface air temperature by using the radiative transfer model. Satellite view and solar zenith angles are also considered in developing algorithms. The applications o f the ABSTRACT algorithms to clear days show that the algorithms provide reasonable estimations of reflectances and Normalized Difference Vegetation Index (NDVI) values compared with the physically based atmospheric radiative transfer model and a good approximation o f surface temperature compared with observation. Although the algorithms are based on the characteristics o f the spectral bands on the National Oceanographic and Atmospheric Administration (NOAA-14) Advanced Very High Resolution Radiometer (AVHRR) sensor, the approaches may by applied to other satellite data.M.S. (Master of Science