Using the Panchromatic band for water column correction to derive water depth and spectral bottom signature: Landsat 8 OLIP bandset used for this work Purple_1, Blue_2, Green_3, PAN_4, Red_5, NIR_6 and SWIR1_7 |
![]() NIR band Note the very strong increase of atmospheric path radiance from west to east ![]() PAN band | ![]() TCC Seatruth USGS's EAARL LIDAR DTM merge_5.tif over Dry Tortugas is overlayed ![]() FCC |
![]() USGS's merge_5.tif LIDAR DTM I have resampled it to 30 resolution, by 6*6 sum aggregation |
Profile RED and Profile Blue Also shows the glint training site in dark blue ![]() Deglinted TCC
![]() Glint regression based on NIR band The atmosphere in this image is quite thick Deglinting efficiently removes this variation in path radiance from West to East: NO NEED FOR ATMOSPHERIC CORRECTION | ![]() Deglinting of Purple, Blue, Green, PAN and RED bands along Profile Red
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Deep water radiance values are derived using the glint regressions. By inspection of a profile of radiances over deep waters at a particular location, I can adjust the deep water radiances according to how I think things might work for the current scene at that location. -Lsw/133.5/095.2/043.1/037.2/023.1/009.6/018.2 -dLsw003.0/003.0/002.0/001.0/000.9/000.0/000.0
Lsw 136.5 98.2 45.1 38.2 24.0 9.6 18.2 This tuning is very sensitive. As it allows to set threshold values at fairly low values, and therefore to extend the effective depth range | Before tuning The result is: Lsw 136.5 98.2 45.1 38.2 24.0 9.6 18.2 |
link to Water volume reflectance Lw Path radiance La The Soil Line for Dry Tortugas National Park surroundings |