in the NIR region (Green et al. 2000) with central maxima at 820 
nm and a secondary peak at 1070 nm in the MIR region. The live 
corals exhibited “brown mode” of coral reflectance with triple- 
peaked pattern in the visible region. All spectra have a 
characteristic spike located at 760 to 762 nm due to the presence 
of atmospheric oxygen. The coral spectra are characterized by two 
distinct absorption features located at 675 nm (chlorophyll 
absorption) and 975 nm (water absorption). The absorption band 
depth at 975 nm is a function of the depth of water column and 
water column does suppress the reflectance magnitude. Ripples 
on moving water column drastically change the spectral shape of 
corals at 840 nm. The live and the bleached coral spectra can be 
well distinguished in the 400 to 600 nm region. The relative 
exposure of coral polyps and corallite structure can be a major 
determinant in the spectral behaviour of the corals at colony scale. 
The first and second order derivatives can be employed to identify 
common reflectance and absorption regions of the coral targets 
along with potential region(s) of separation between live and 
bleached corals. Live and bleached corals get differentiated with 
first-order derivatives at 631 and 647 nm while 680 to 700 nm 
window show their clear separation with second-order derivatives 
However, bleached coral target needs to be sampled more in order 
to strengthen these observations. Derivative analysis needs to be 
investigated in depth and with more number of samples to 
comment on the spectral separability of the coral targets. 
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7, ACKNOWLEDGEMENTS 
This study presents the preliminary results of the work being 
carried out under Optical Characterization of Coral Reef Diversity 
Project under Meteorology and Oceanography Programme of 
Space Applications Centre, ISRO. The author is thankful to 
Director, Space Applications Centre and Dr. J. S. Parihar, Deputy 
Director, EPSA for overall technical guidance and support for this 
study. The work has been carried out in collaboration with GEER 
Foundation, Gandhinagar. The author sincerely acknowledges the 
contribution of all the members of project team of GEER 
Foundation and Space Applications Centre, ISRO.