Verification of Optical Depth Retrievals From High Resolution Satellite Imagery

摘要

A new technique has been developed using high resolution satellite imagery to derive aerosol optical depths by measuring the difference of the radiances inside and outside of shaded regions Vincent (2006). This approach has shown promise as a new means of providing aerosol optical depth in regions that have proven difficult using more traditional means. Initial studies have been done primarily over desert/arid environments with some limited work over urban regions. This thesis takes the next step by focusing on the challenges that come along with using this technique in an urban environment and by exploring the relationship of how this technique is affected by different surface types. Four different surface types were examined, dirt, grass, pavement, and other which includes a random sampling of surfaces that are commonly found in urban environments. Three of these surface types act remarkably similar while grass surfaces deviate from the results seen with the other surfaces. Results from all the surfaces show a low bias which was not seen in the earlier study. This low bias can possibly be attributed to the aerosol model used when running the Shadow Method program, urban effects.