fk_20200307

Investigating a LUT approach using Landsat 8 data

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Landsat 8 at Florida Bay
scene acquired March 7th 2020, courtesy of USGS
work done march 2021
see NOAA chart 11452
see NOAA chart 11433
see NOAA chart 11451

**The Data: several challenges**

Florida Bay East tide ~0.4 m; FloridaBay West tide ~0.6 m

shallow silty(?) waters of Gulf of Mexico

inland fresh waters flowing from Everglades Park over Florida Bay

possibly confined waters in isolated Florida Bay marine lakes

clear oceanic waters in Straight of Florida?
TCC	FCC
Glint regressions	TCC deglinted, TOA

**Optical calibration over the full image**
Full image calibration Blue, Green, Red and NIR OII water type of Jerlov in Straits of Florida	Full image calibration Blue, PAN, Red and NIR Panchromatic band under nice control

**Optical calibration for eight ROIs**

Gulf waters probably do not achieve bottom detection:

possibly silty waters

Straits of Florida exhibits Oceanic OII water type of Jerlov

Eastern Florida Bay exhibits Oceanic OII water type of Jerlov?

sparse seagrass, very bright bottoms

Central Florida Bay is under influence of Everglades Park fresh waters

up to Coastal C7 water type of Jerlov: see Orange and Turquoise ROIs

abundant seagrass beds
ROIs The above calibration applies to the clearest waters in the whole image. This is likely to be located along the outer reefs: Straits of Florida. The Florida Bay remarkably harbours a number of confined and very shallow marine "lakes" which possibly host less clear waters, under the influence of the Everglades waters.	Mask_3 orange ROI Following the BPL assumption: Kgreen/Kred =0.733/1.199=0.61 Kblue /Kred =1.027/1.199=0.86 Kblue /Kgreen=0.86/0.61=1.40 This ROI exhibits Coastal C5+0.4 water type This applies down to ~2 m Depths in his ROI do not exceed ~2 m
Mask_4 turquoise ROI Turquoise ROI exhibits Coastal C7 water type Depths in his ROI do not exceed ~2 m	Mask_5 blue ROI It is very clear that Kblue=Kgreen=0.278 Blue ROI exhibits Oceanic OIII water type Depths in this ROI do not exceed ~2 m
Mask_6 red ROI It is clear that Kblue=Kgreen=0.278 Red ROI exhibits Oceanic OIII+0.5 water type Depths in his ROI do not exceed~ 2 m	Mask_7 green ROI It is clear that Kblue=Kgreen=0.278 Green ROI exhibits Oceanic OIII+0.5 water type Depths in this ROI do not exceed 1.2 m
Mask_8 white ROI It is very clear that Kblue=Kgreen=0.278 Depths in his ROI do not exceed~ 2 m	Mask_10 purple ROI Kblue/Kred =0.124/0.823=0.151 Kgreen/Kred =0.124/0.823=0.239 Kblue/Kgreen=0.151/0.239=0.632 Evidence here is unquestionable Purple ROI exhibits Oceanic OII water type Depths in this ROI exceed 25 m

**LUT results V3**
LUT: map of the ratio Kblue/Kgreen	LUT: SDB see legend
LUT: Corrected reflectance UGB TCC UltraBlue, Green, Blue RGB