 FCC TCC |  TCC deglinted |
 Normalized true color composite of computed bottom reflectance Hard to beleive that the lagoon bottom is all covered in dark vegetation! | Average computed bottom reflectance The very dark patch at the center of the lagoon seems dubious. More probably, the waters there are much less clear than further west where open ocean waters move in and out with the tide. The close study of the calibration diagrams shall help us ascertain that |
 Computed depth is in excess of 14 m in the lagoon | It is quite clear that these computed water depths are far too shallow: an average of ~5 m |
Healthy coconut groove - These are BOA radiances scaled so that a bright sandy beach would plot at 200 for all bands
- The specification of blue bands, green bands and red bands is derived from this sort of plot: the average BOA blue reflectance is approximately equal to the average BOA red reflectasnce
- ==> BlueGreen=500 nm
- ==> GreenRed=625 nm
- this is entered in the -KK... argument: -KK4_21_0.200/Knir5.499/Bm440_BG500_GR625_RN700
| Bright green shallow bottom: Z=1.77 m These are BOA radiances scaled so that a bright sandy beach would plot at 200 for all bands |
 Darker blue shallow bottom: Z=2.63 m |  Darker green deeper bottom: Z=5.57 m |
 Calibration diagram for bands Blue=4, Green=11, Red=21 and Nir=26 | Calibration - BPL assumption: the most remarquable feature of this calibration is that the BPL assumption is demonstrated to apply, as this atoll exhibits clean bright shallow bottom substrates from null depth down to optically deep waters in the Tarawa lagoon
- this substrate is a fine grained snow-white mud which mostly comes from the green algae Halimeda which is coated with a thin white calcium carbonate shell
- Water type ~OII+0.2: the BPL model is seen to fit quite closely to Jerlov's estimaded water type
- K[nir]~=5.5 here
|
 Calibration diagram for bands 23, 24, 25 and 26 |  Calibration diagram for bands 10, 15, 20 and 25 |