4SM on OLI at Caicos Bank, Bahamas

Optical calibration, bathymetry, water column correction and bottom typing of shallow marine areas, using passive remote sensing imageries
Bathymetry and water column correction

LANDSAT 8 OLIP
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_1, Blue_2, Green_3, PAN_4, Red_5, NIR_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
home

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: La_NIR~=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 K_BLUE/K_GREEN is modeled decreasing 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