As of 2021,
4SM now implements a simplified LUT process,
as introduced by Hedley et al, 2009


home
 
 
Landsat 8 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























calibration Blue, Green, Red and NIR
OII water type of Jerlov in Straits of Florida

 


calibration Blue, PAN, Red and NIR
Panchromatic band under nice control

 

 
Work in progress
Optical calibration  for several 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 (Straight 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 national Park inland 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 applies down to ~2 m
  • This ROI exhibits Coastal C5+0.4 water type of Jerlov. Depths in his ROI do not exceed 2 m

                 Mask_4 turquoise ROI       
                              
  • This ROI exhibits Coastal C7 water type of Jerlov.
  • Depths in his ROI do not exceed 2 m

             Mask_5 blue ROI                 
                       6 5 3 2   ==>>0.63                         
  • It is very clear that Kblue=Kgreen=0.278
    • Blue ROI exhibits Oceanic OIII+0.5 water type
  • Depths in his ROI do not exceed 2 m

Mask_6 red ROI
  • It is very 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 very 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


?????

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
  • This is quite a strong finfing
    • with unquestionable evidence
  • Purple ROI exhibits Oceanic OII water type


 
 
 
 
 
 
 
 
 
 



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