ATMOSPHERIC CORRECTION OF LANDSAT THERMAL INFRARED DATA: A CALCULATOR BASED ON NORTH AMERICAN REGIONAL REANALYSIS (NARR) DATA

摘要

In order to utilize Landsat thermal infrared data, we must account for atmospheric effects. Atmospheric correction applications currently available for this purpose either do not allow the user to specify atmospheric profiles for the desired time and location of the Landsat overpass and/or do not cover the entire Landsat operational period. To address these problems, we have developed an atmospheric correction application for the thermal infrared bands of Landsat-5 TM and Landsat-7 ETM+ that is applicable to North America and based on the MODerate spectral resolution atmospheric TRANsmittance algorithm and computer model (MODTRAN). Specifically, we have designed Interactive Data Language (IDL) programs to extract the desired atmospheric data from the North American Regional Reanalysis (NARR) data based on user inputs of latitude, longitude, elevation, and Landsat overpass time. The application reformats the atmospheric data and adds it to tape 5 inputs used in execution of MODTRAN. The application uses the MODTRAN tape 7 outputs to calculate atmospheric transmission, upwelling radiation and downwelling radiation parameters. We have compared our application with the online Atmospheric Correction Parameter Calculator (ATMCORR) that has been available to the public since 2003 (http://atmcorr.gsfc.nasa.gov). Comparisons using the two applications' normal atmospheric data types (NARR, NCEP) showed that parameter variances coincided with differences in the lowest portion of the atmospheric profile, indicating that the different methods used to handle this part of the profile may be the principle cause of variation between the applications.