A 1401*1006 EO1-ALI 6 bands 16-bits image of Salar de Coipasa, Bolivia. January 26th, 2003
A 597*1554 EO1-Hyperion 26 bands 16-bits image of Salar de Coipasa, Bolivia.  June 5th, 2004

image EO1A0010732003026110PZ, courtesy of USGS_Glovis; this image subset is 42 km across , pixel size 30 m
Salar de Coipasa is a slat flat located in the Atacama desert in Bolivia, at an altitude of ~3700 m.

It provides the opportunity to investigate the linearity of the linearized simplified radiative transfer
at extremely shallow depths over a uniform and very bright bottom, just like Tarawa atoll.
Because depths hardly exceed ~ one meter, the deep water radiances may not be estimated for the visible bands.
This is not too much of a problem though, as the Lw term is mostly important at depth over dark bottoms;
non vegetated desert land and cloud shadows allow for a fairly good estimate of atmospheric path radiance.

 



 
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
 

 ALI
Hyperion


home




 


A 1401*1006 EO1-ALI 6 bands 16-bits image of Salar de Coipasa

 
Band
1 2 3 4 5 6
Colour blue blue green red nir nir
WL in nanometers 443.0 482.5 577.0 660.0 790.0 867.5


Raw image, true color composite
 


Raw image, false color composite
 



Bottom reflectance, true color composite
 

 

<== Bottom reflectance

 

  • <== The scene is seen "as if there was no water"
  • The bottom of the salar is said to be lined with a layer of pink algae (Wikipedia) on which flamingoes feed.
  • We see here that this appears to be limited to the north-east part of the moat.
  • The transition from bright bottoms to darker bottoms is absolutely not related to depth.
  • The darkening of the bottoms is likely to be related to
    • river discharge, bringing nutrients and sediments
    • and subsequent development of a pink algal mat, high in red, low in blue
  • rather than any kind of depth or water stratification effect

Computed depth
 

Average bottom brightness
 

image WZ

Green: almost all shallow pixels are modeled based on the NIR band at 867 nm
Purple: only a few darkest/deepest (?) spots are modeled based on the NIR band at 790 nm


 
 

Black line

  • This line runs along the fairly sharp transition from uniform and very bright bottoms towards darker bottoms closer to the river mouth
    • without any correlation with computed depth!!

Calibration_diagram_6_5_4_2 full image

Calibration_diagram_6_5_4_1 full image

Calibration_diagram_5_4_3_1 full image

Calibration_diagram_4_3_2_1 full image

  •   Optical water type ~C1+0.26 in a low water situation
  • Wavelengths used are 482.5, 660.0, 790.0, 867.5 nm
  • Calibration appears to be quite reliable, in spite of the fact that the water is probably a saturated brine
  • Depths do not seem to exceed
    • ~0.7 m over the brightest bottoms
    • ~1.3 m over the darkest bottoms in the moat
  • Linearity: please note that the linearized data for all bands fully confirm that the simplified radiatice transfer model is really linear over the whole NIR depth range, as already seen in

Calibration diagram for the Blue/Red pair


#Salar de Coipasa  Salar de Coipasa  Salar de Coipasa  Salar de Coipasa  Salar de Coipasa  3,656 meters above the mean sea level
#/home3/ymorel/4SM/compile.sh;
#rm *gli *cal
#rm 4sm.def
#nice -20  4SM.3.21 -Process/14_JAN_2010 -Origin/USGS                           
-DB//0037_0_6_0/6_38/1401_1006/557.355_7885.995/1_1                           
-Mis/Andes/Salar_de_Coipasa/EO1/ALI/USGS/UTM_19_008/0.030_0.030/26_JAN_2003               
-MakePIX /FILE/8/Z20                                           
-import/data*/dbnc_0_1_0_0/R1751_L3221/import_555.900_7941.900                        
-M@0000001/@0002/00003/00004/00005/00006                               
-LS0009999/09999/09999/09999/09999/09999                               
@SCL/00722/00830/01232/01727/02159/02018                               
-SCL/00706/00832/01235/01714/02294/02280_new                               
-Lsw/042.7/033.7/023.9/019.6/013.2/009.8_new                               
-La/0039.6/030.7/020.9/017.6/013.2/009.8_new                               
-LsM/200.0/200.0/200.0/200.0/200.0/200.0_new                               
-Lm/0001.0/001.0/001.0/001.0/000.2/000.9_new                               
@deglint/vRba/DegTol1.00/F2/L6/GlintM95.0/FN/mDEGLINT1                           
-AutoCAL/Print_3_4/mapBPL/MakeNewMask/getGlint/glintM50.0/clouds                   
-smooth/5/D/Smart+ @-DN878/977/5BrightBeach @-DN1216/264/5Lsw
 

#exit


#Following is the full CommandLine=====mBPL=2==================================
#/home3/ymorel/4SM/compile.sh
nice -20  4SM.3.21 -Process/08_JAN_2010 -Origin/USGS               
-DB//0037_0_6_0/6_38/1401_1006/557.355_7885.995/1_1   
-Mis/Andes/Salar_de_Coipasa/EO1/ALI/USGS/UTM_19_008/0.030_0.030/26_JAN_2003   
@-URL/file:///home/ymorel/RSPwebsite/website/                   
-makePIX/FILE/0/Z20                               
-WLM/453.0/515.0/605.0/690.0/805.0/890.0                   
-WLm/433.0/450.0/525.0/630.0/775.0/845.0                   
-cWL/0.500/0.500/0.500/0.500/0.100/0.500                   
-cWL/0.500/0.500/0.650/0.500/0.500/0.500                   
-M/@000001/@0002/@0003/00004/00005/00006                   
-LS0009999/09999/09999/09999/09999/09999                   
@CP/182.1/190.5/190.2/142.3/50.1/23.2_0.50m                   
@CP/190.1/190.5/182.2/143.8/49.1/22.7_0.50m                   
-dLsw00000/000.0/00000/000.0/0-1.0/0-0.5                   
-SCL/00706/00832/01235/01714/02294/02280_new                   
-Lsw/042.7/033.7/023.9/019.6/013.2/009.8_new                   
-La/0039.6/030.7/020.9/017.6/013.2/009.8_new                   
-LsM/200.0/200.0/200.0/200.0/200.0/200.0_new                   
-LsM/216.0/216.9/217.9/218.2/218.7/219.0_CoefLM=1.10               
-LsM/221.0/216.9/212.9/220.2/218.7/219.0_CoefLM=1.10               
-Lm/0001.0/001.0/001.0/001.0/000.2/000.9_new                   
-KK2_4_0.3235/Knir5.500/Bm400_BG500_GR600_RN700                   
-Z/MSL0.00/zplus/cSL1.18/ZMax0.00/cdZ1.00/PAN_1_6/sIG_4w0/n_0/cZ1.000       
-B/tclNe2.00/LBref200_100/Bmin0/cLM1.03                   
-B/tclNe2.00/LBref200_100/Bmin0/cLM1.22                   
@deglint/vRba/DegTol1.00/F2/L6/GlintM10/FN/mDEGLINT1               
-extract/v/NIRband6/NIRmax1000/mBPL2/mSOIL21 /Ext_1_1401_1_1006           
@Calibrate/v/BdSNpz/BC_6_5_3_2/BDh_12_13_24                   
-calibrate/v/BdSNpz/BC_6_5_4_2/BDh_12_23_34                   
-Model/mask_4    @-Tc2/3                               
-smooth/1/D/Smart+                               
@-E80/210/300/570                               
-dCAL/A/2_4/18    @-E1/1401/1/1006 @-E1/1401/1/1006               
-ProfileABZ/profile/profile_1/1_2_3_4_5_6                   
@-DD1132/337


exit


#Following is the full CommandLine=====mBPL=2==================================
/home3/ymorel/4SM/compile.sh
nice -20  4SM.3.21 -Process/08_JAN_2010 -Origin/USGS               
-DB//0037_0_6_0/6_38/1401_1006/557.355_7885.995/1_1   
-Mis/Andes/Salar_de_Coipasa/EO1/ALI/USGS/UTM_19_008/0.030_0.030/26_JAN_2003   
@-URL/file:///home/ymorel/RSPwebsite/website/                   
-makePIX/FILE/0/Z20                               
-WLM/453.0/515.0/605.0/690.0/805.0/890.0                   
-WLm/433.0/450.0/525.0/630.0/775.0/845.0                   
-cWL/0.500/0.500/0.500/0.500/0.100/0.500                   
-cWL/0.500/0.500/0.650/0.500/0.500/0.500                   
-M/@000001/@0002/@0003/00004/00005/00006                   
-LS0009999/09999/09999/09999/09999/09999                   
@CP/182.1/190.5/190.2/142.3/50.1/23.2_0.50m                   
@CP/190.1/190.5/182.2/143.8/49.1/22.7_0.50m                   
-dLsw00000/000.0/00000/000.0/0-1.0/0-0.5                   
-SCL/00706/00832/01235/01714/02294/02280_new                   
-Lsw/042.7/033.7/023.9/019.6/013.2/009.8_new                   
-La/0039.6/030.7/020.9/017.6/013.2/009.8_new                   
-LsM/200.0/200.0/200.0/200.0/200.0/200.0_new                   
-LsM/216.0/216.9/217.9/218.2/218.7/219.0_CoefLM=1.10               
-LsM/221.0/216.9/212.9/220.2/218.7/219.0_CoefLM=1.10               
-Lm/0001.0/001.0/001.0/001.0/000.2/000.9_new                   
-KK2_4_0.3235/Knir5.500/Bm400_BG500_GR600_RN700                   
-Z/MSL0.00/zplus/cSL1.18/ZMax0.00/cdZ1.00/PAN_1_6/sIG_4w0/n_0/cZ1.000       
-B/tclNe2.00/LBref200_100/Bmin0/cLM1.03                   
-B/tclNe2.00/LBref200_100/Bmin0/cLM1.22                   
@deglint/vRba/DegTol1.00/F2/L6/GlintM10/FN/mDEGLINT1               
-extract/v/NIRband6/NIRmax1000/mBPL2/mSOIL21 /Ext_1_1401_1_1006           
@Calibrate/v/BdSNpz/BC_6_5_3_2/BDh_12_13_24                   
-calibrate/v/BdSNpz/BC_6_5_4_2/BDh_12_23_34                   
-Model/mask_4    @-Tc2/3                               
-smooth/1/D/Smart+                               
@-E80/210/300/570                               
-dCAL/A/2_4/18    @-E1/1401/1/1006 @-E1/1401/1/1006               
-ProfileABZ/profile/profile_1/1_2_3_4_5_6                   








 

 
A 597*1554 EO1-Hyperion 26 bands 16-bits image of Salar de Coipasa, Bolivia.  June 5th, 2004

image EO1H0010732004157110PY, courtesy of USGS_Glovis; this image subset is 7.8 km across , pixel size 30 m

26 bands used: band spacing is 10 nm from 447.2 nm to 691.4 nm, NIR is at 844.0 nm


Raw image, false color composite
 
 
 
Computed depth
 
 
 
True color composite
of spectral bottom reflectance
 
Average bottom brightness
 
 
Calibration diagram
for Blue, Green, Red and NIR bands
 
Optical water type ~OIII+0.3 in a low water situation
Quite frustrating though,
as the depth does not exceed ~1 m in june 2004
 
 
 
 
  • Lsw and La: quite difficult, as La and Lsw have to be bestimated using expert knowledge
  • Very shallow bottoms: quite interesting, as the simplified radiative transfer equation is seen to apply in a straightforward manner at very shallow depths over very bright and uniform bottoms
  • Jerlov's classification: quite rewarding, as it is seen to apply in a straightforward manner to hyperspectral data and to clear briny waters,
    • it is seen that the 575-600 nm region of the spectrum would need to be resolved with more closely spaced attenuation sample data
    • this is a cause of difficulties when using wideband data like Landsat ETM or EO1-ALI
#/home3/ymorel/4SM/compile.sh
#nice -20  4SM.3.22 -Process/04_FEB_2010       -OriginUSGS           
-dB/EO1H0010732004157110PY/63_1_26_0/26_65/597_1554/584.565_7896.555/1_1   
-Mis/Bolivia/Salar/EO1/HYPERION/USGS/UTM_19_008/0.030_0.030/05_JUN_2004       
-MakePIX                                   
@import/data*EO1H0010732004157110PY/dbnc_0_1_0_0/R961_L3201/import_584.100_7944.000_10000                                   
-LS00500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0   
-Lm/0000.7/000.7/000.7/000.7/000.7/000.7/000.7/000.7/000.7/000.7/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3_new       
-SCL/01013/01064/01111/01172/01125/01136/01151/01113/01166/01159/01161/01160/01111/01088/01064/01038/01075/01037/01000/01000/00960/00926/00975/00963/00859/00905_by4SM       
-Lsw/036.1/035.0/034.0/033.4/031.8/031.0/029.4/027.9/027.2/025.9/020.4/019.4/017.6/019.6/020.9/022.3/021.4/019.1/017.7/018.3/018.4/017.4/016.5/015.4/017.0/002.2_new       
-La/0018.4/017.3/016.7/015.4/014.4/013.6/012.3/011.6/013.5/015.3/015.0/016.2/016.5/018.6/020.1/021.6/020.9/018.8/017.7/018.3/018.4/017.4/016.5/015.4/017.0/002.2_LAMin       
@extract/v/NIRband4/NIRmax5.0/mBPL3/mSOIL21 /Ext_3000_6800_2300_5800       
-AutoCAL/print_2_3/mapBPL/MakeNewMask/getGlint/glintM20.0/clouds        
-smooth/1/D/Smart+                                
@-DN184/1187/5Bright @-DN321/567Deep   
 
#exit
 
#Following is the full CommandLine=====mBPL=2==================================
#/home3/ymorel/4SM/compile.sh
nice -20  4SM.3.22 -Process/4_FEB_2010    -OriginUSGS               
-DB/EO1H0010732004157110PY/63_1_26_0/26_65/597_1554/584.565_7896.555/1_1   
-Mis/Bolivia/Salar/EO1/HYPERION/USGS/UTM_19_008/0.030_0.030/5_JUN_2004       
@-URL/file:///home/ymorel/RSPwebsite/website/                   
-makePIX/FILE/0/Z20                               
-LS/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0/500.0           
-WLM/452.2/462.3/472.5/482.7/492.9/503.0/513.2/523.4/533.6/543.7/553.9/564.1/574.3/584.5/594.6/604.8/615.0/625.2/635.3/645.5/655.7/665.8/676.0/686.2/696.4/849.0       
-WLm/442.2/452.3/462.5/472.7/482.9/493.0/503.2/513.4/523.6/533.7/543.9/554.1/564.3/574.5/584.6/594.8/605.0/615.2/625.3/635.5/645.7/655.8/666.0/676.2/686.4/839.0       
-cWL/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500/0.500       
-M/@000001/@0002/@0003/@0004/@0005/@0006/@0007/@0008/@0009/@0010/@0011/@0012/@0013/@0014/@0015/@0016/@0017/@0018/@0019/@0020/@0021/@0022/@0023/@0024/@0025/00026  
-CP/0183.2/190.9/196.2/203.5/206.5/211.6/214.1/207.2/202.7/200.7/197.9/195.8/197.7/194.7/195.6/181.0/158.9/151.2/147.5/140.7/145.0/134.8/12.0/117.2/119.8/010.0_0.75m       
-LsM/233.5/236.5/235.1/243.5/237.2/239.2/239.8/234.8/230.8/230.2/229.0/229.2/232.8/235.3/242.3/248.8/237.5/236.3/240.1/237.8/249.3/245.1/236.7/238.3/255.9/166.8_CoefLM=0.83   
-Lm/0000.7/000.7/000.7/000.7/000.7/000.7/000.7/000.7/000.7/000.7/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3/001.3_new       
-SCL/01013/01064/01111/01172/01125/01136/01151/01113/01166/01159/01161/01160/01111/01088/01064/01038/01075/01037/01000/01000/00960/00926/00975/00963/00859/00905_by4SM       
-Lsw/036.1/035.0/034.0/033.4/031.8/031.0/029.4/027.9/027.2/025.9/020.4/019.4/017.6/019.6/020.9/022.3/021.4/019.1/017.7/018.3/018.4/017.4/016.5/015.4/017.0/002.2_new       
-La/0018.4/017.3/016.7/015.4/014.4/013.6/012.3/011.6/013.5/015.3/015.0/016.2/016.5/018.6/020.1/021.6/020.9/018.8/017.7/018.3/018.4/017.4/016.5/015.4/017.0/002.2_LAMin       
-KK4_21_0.35146/Knir4.500/Bm440_BG500_GR600_RN700                   
-Z/MSL0.00/zplus/cSL1.18/ZMax0.00/cdZ1.00/PAN_1_26/sIG_0w0/n_0/cZ1.000       
-B/tclNe5.00/LBref200_100/Bmin0/cLM1.0                       
@deglint/vRba/DegTol1.00/F1/L26/GlintM25.0/FN/mDEGLINT1               
-extract/v/NIRband26/NIRmax1000/mBPL2 /Ext_1_597_1_1554               
@Calibrate/v/BdSMpz/BC_26_25_24_23/BDh_12_23_34                   
-Calibrate/v/BdSNpz/BC_26_21_11_4/BDh_12_13_34                   
-Model/mask_2    @-Tc4/11                           
-Smooth/0/d/smart-                               
-dCAL/A/4_21/38    @-E1/597/1/1554 @-E1/597/1/1554                   
@-DN184/1187/5Bright @-DN321/567Deep @-DN368/1051