Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries
Bathymetry and water column correction
at Caicos Bank, Bahamas 
4018*4149, 30 m pixel size, UTM zone 18, downloaded from USGS
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_1Blue_2Green_3PAN_4Red_5NIR_6 and SWIR1_7

Please refer to Bora Bora and Sanaa
for use of the PANchromatic band 
and for water column correction

scene LC80090452014216LGN00, Aug 4th  2014
work done august 2016
This is summer time in the Bahamas


DTM seatruth  RMSE=0.59 m
ZDTM - Z4SM in centimeters
tide correction applied 0.8m
see legend
Z4SM vs ZDTM regression

tide correction applied 0.8m

Z4SM and ZDTM along profile_green
no tide correction applied
see location of this profile

Z4SM vs ZDTM along profile_green
no tide correction applied
see location of this profile

Data and Deglinting

TOA FCC: raw image
linear enhancement
density of the atmosphere increases dramatically
from NW to SE

TOA TCC: raw image

This is a low-tide image:
no tide correction needed


From NW to SE
accross the whole imge
  • NIR increases from 30 to 60
    • this is a lot of "glint" that mudst be subtracted
  • NIR is as low as 14 under cloud shadow
    • this is a dense atmosphere: LaNIR~=14

Glint regressions are excellent
  • this is a feature of very dense atmospheres

BOA TCC deglinted
linear enhancement

Optical calibration, optimized
16U data are scaled to allow for comfortable screen display

Calibration diagram for the whole scene
for bands Blue, Green, Red and NIR
KBLUE/KGREEN is modeled
from 0.68 (0-6 m) to 0.47 at depth

This is done through four -CP... arguments


Calibration diagram for the whole scene
for bands Coastal, Blue, PAN, and Red

Reflectance (0-1)
of the path radiance Ra for this scene
0.108 0.086 0.056 0.051 0.038 0.024 0.012

Reflectance (0-1)
of the water volume Rw for this scene
0.010 0.007 0.001 0.001 0.0 0.0 0.0


Now ready for Modeling
Smoothing applied
PAN solution applied

BOA TCC water column corrected
scaled 0-250
no enhancement


Retrieved depth


Bottom typing
SAM classified image
This is August 2014

see legend for SAM

ImageB: average bottom brightness
This is August 2014


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