Spectra 20, 21 and 22 were taken at the surface of 

 the water. These spectra v;ould have contributions from 

 upwolling and reflected light. Again, the depression angle 

 of the spectrometer was 80°. 



Spectra 25 and 26 were obtained by depressing the 

 spectrometer by about 80° and viewing the gray card. These 

 measurements indicate the dov.'nv;e] ling irradiancc at the time 

 of the measurements. The gray card is assumed to have 0.18 

 diffuse reflectivity coefficient over the spectral response 

 of the instruments. 



1. All spectra should be matched in wavelength scales 

 when overlaying for comparison. 



2. The ir radiance scales on all spectra have been 

 normalized to '9 inches. Hence, structural details between 

 spectra can be compared readily while quantitative irradiance 

 differences are not V7ell obtained by direct overlay. 



3. The weak structure residing on top of the broad 

 spectra is probably noise and should be treated as such unless 

 it has regular repeatability from spectrum to spectrum. 



o o 



4. The data from 7000 A to 8000 A is noise dominated. 



5. As a first step, the internal consistency of the 

 experiment is best validated by comjiarijig 25 and 25 (gray card). 

 A direct overlay shows almost ddentica] spectral structure versus 



29-4 



