Bathymetry and water column correction
LANDSAT 8 OLIP 
at Shark Bay and Hamelin Pool, Western Australia

4395*5915, 30 m pixel size, UTM zone 49
scene LC80090452013133LGN01, April 18th 2013 downloaded from USGS
Work done september 2013
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_1Blue_2Green_3PAN_4Red_5NIR_6 and SWIR1_7

Please refer to Bora Bora and Sanaa
for use of the PANchromatic band for water column correction
 
 
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Water column correction: retrieved depth
Performance of the PAN band reaches in excess of ~20 m over bright bottoms in this OIB water type of Jerlov
 

Retrieved depth 
NOT CORRECTED FOR TIDE HEIGHT

also shows Profile Red


 
  • Hamelin Pool is reported to reach a depth of 9.4  m LWM datum.
    • Tide height ~1.3 m on 18_APR_2013 11:00 AM at Canarvon, Shark Bay
    • this translates into 10.7 m maximum
  • Dense segrass beds still cause a excess depth artifact
  • Wooramel Delta is flooded at high tide



Retrieved depth along Profile Red
  • Profile C straddles the seageass bank
  • Profile B crosses Hopeless Reach, then Faure Sill, then Hamelin Pool
  • Profile A crosses Freycinet Reach then Freycinet Harbor
 
Water column correctd reflectance profiles
are shown for the Purple, Blue and Green bands







Water column correction of visible bands

Raw image TCC
for bands Blue, Green and Red

Water column corrected TCC
for bands Blue, Green and Red
Note
The above two TCCs  are TOA reflectances in original image DN units, after subtraction of an offset=5000  and scaling to the 8 bits range using strictly identical enhancement

 




Results at Hamelin Pool

Retrieved depth
also shows Profile_black

 

Retrieved  depth along Profile Black
also shows water column corrected bottom reflectance
for bands Purple, Blue and Green
  • upper : profile_black_C
  • middle: profile_black_B
  • lower  : profile_black_A

TCC
 

Water column corrected TCC
Note:

artifacts in retrieved depth
correlate with variations in bottom reflectance


 



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