1 - NO NEED for field data, nor for atmospheric correction
2 - this is demonstrated in this website, using a variety of hyper/multi spectral data
 
Requirements are
1 - homogeneous water body and atmosphere
2 - some coverage of optically deep water
3 - some coverage of dry land
 
Problems are
1 - the precision on estimated depth is found wanting, because the noise-equivalent change in radiance  of accessible data is too high for shallow water column correction work 
2 - radiance data should be preprocessed by the provider at level 1 in order to improve S/N ratio
3 - exponential decay: the deeper/darker the bottom, the poorer the performances
 
So
I keep digging
until suitable data
become available
 
 

TCC raw linear enhancement
Hamelin Pool
is located at the SE of Shark Bay in western Australia

 

TCC deglinted histeq enhancement



 
 
Blue band deglinted

 
* There is abundant negative bottom contrast in band ETM_1
* Not easy to settle for a Lsw
blue   value



 

Green band deglinted

 
* A body of turbid waters is seen pouring out of SharkBay

* Red band deglinted bottom detection is only observed in a ~300 m wide strip along the water line: the bottom of Hamelin Pool shows no bottom detection in the Red band 

 
 
computed depth Z

 



 
  • Modeling in the salt ponds is not appropriate, as deep water radiance may not be estimated
  • Freycinet Basin appears to be extremely complex, while Hamelin Pool and Lharidon Basin are quite simple
  • We obtain a maximum computed depth ~=7.5 m in Hamelin Pool where the bottom is brightest, whereas hydrography shows a MaxDepth ~=8 m (though at another location!)
  • Tide height: the tide height relative to the hydrographic data is not known. The offset in Fig. 7 might simply be caused by the M=0 factor in Bierwirth's method, instead of giving a measure of the tide height.
 
Final Z= CoefZ*Computed Z + TideHeight
where TideHeight and CoefZ
may only be obtained using seatruth 





 

TCC of water column corrected bottom reflectance

 
* No enhancement: radiances are BOA: this is a "low tide view"
* The dark diatom ooze area is well visible in the southern part of Hamelin Pool

 

average bottom reflectance B

 
* The processing of darkest areas required the introduction of special conditions in 4SM code
* These areas at a depth of 2-5 m have a quasi-null reflectance in the blue band: depth results are all the more questionable

 

Calibration diagram
for the whole image

Very clear waters
  • Waters appear to be stratified
    • water type ~ OII  +0.34 0-5 m
    • water type ~ OIB+0.69 at depth

 


 

Calibration diagram
for HamelinPool/LharidonBasin

Very clear waters
  • Waters appear to be stratified at Hamelin Pool
  • water type ~OII+0.49 0-4 m
  • water type ~ OII+0.27 at depth
  • Waters in Hamelin Pool are hypersaline
  • though fresher waters seem to be sligthly denser/cooler/clearer than hypersaline waters above
 
 
nice -20 4SM.4.01 -Process/14_JAN_2011 -OriginNPA
-DB/L71115078_07820000812/31_1S_0_0/4_1/5541_5297/662.745000_-2796.315000/1_1
-Mis/Australia/SharkBay/Landsat/ETM/USGS/UTM_49_008/0.030_-0.030/12_AUG_2000
-LS/0255.0/255.0/255.0/255.0
-WLM/513.9/600.7/692.0/898.0
-WLm/441.3/519.4/630.6/771.6
-cWL/0.450/0.650/0.350/0.500
-M/@000001/00002/00003/00004
-CP/101.87/073.26/022.96/010.00_mask_2
-CP/075.71/036.47/017.16/010.00_10.00m
-CP/066.89/029.63/017.13/010.00_22.00m
-dLsw004.0/001.0/00000/00000
-Lm/0001.0/000.2/002.5/255.0
-LsM/155.5/175.4/248.8/210.3
-Lsw/51.85/26.86/17.13/10.00
-Lw/0006.5/001.5/000.0/000.0_1.1 .3 06
-KK1_2_0.4456/Knir4.500/Bm400_BG500_GR600_RN700 /mask_2
-Z/MSL0.00/zplus/cSL1.18/ZMax0.00/cdZ1.00/PAN_1_4/sIG_0w0/N_1/cZ1.000 1
-B/tclNe5.00/LBref200_100/Bmin0/cLM1 .1
-deglint/vRbaD/DegTol1.00/F1/L4/GlintM15.0/FN/mDEGLINT1
-extract/v/rawBDH/NIRband4/NIRmax5.0/mBPL2/mSOIL21/FullBDH
-calibrate/v/BDSNpZG/BDh_12_13_14
-Model /mask_2 -Smooth/5/D/Smart+
nice -20 4SM.4.01 -Process/14_JAN_2011 -OriginNPA
-DB/L71115078_07820000812/31_1S_0_0/4_1/5541_5297/662.745000_-2796.315000/1_1
-Mis/Australia/SharkBay/Landsat/ETM/USGS/UTM_49_008/0.030_-0.030/12_AUG_2000
-LS/0255.0/255.0/255.0/255.0
-WLM/513.9/600.7/692.0/898.0
-WLm/441.3/519.4/630.6/771.6
-cWL/0.450/0.650/0.350/0.500
-M/@000001/00002/00003/00004
-CP/101.87/073.26/022.96/010.00_mask_2
-CP/075.71/036.47/017.16/010.00_10.00m
-CP/066.89/029.63/017.13/010.00_22.00m
-dLsw004.0/001.0/00000/00000
-Lm/0001.0/000.2/002.5/255.0
-LsM/155.5/175.4/248.8/210.3
-Lsw/51.85/26.86/17.13/10.00
-Lw/0006.5/001.5/000.0/000.0_1.1 .3 06
-KK1_2_0.4456/Knir4.500/Bm400_BG500_GR600_RN700 /mask_2
-Z/MSL0.00/zplus/cSL1.18/ZMax0.00/cdZ1.00/PAN_1_4/sIG_0w0/N_1/cZ1.000 1
-B/tclNe5.00/LBref200_100/Bmin0/cLM1 .1
-deglint/vRbaD/DegTol1.00/F1/L4/GlintM15.0/FN/mDEGLINT1
-extract/v/rawBDH/NIRband4/NIRmax5.0/mBPL2/mSOIL21/FullBDH
-calibrate/v/BDSNpZG/BDh_12_13_14
-Model /mask_2 -Smooth/5/D/Smart+