SYNTHESIS OF REQUIREMENTS 
Table 2. Recommended Visible and Near-Infrared Bands (Minimum) 
for the Baseline SeaWiFS Instrument. 
Phenomenon 
Chlorophyll 
Absorption 
Pigment 
Absorption 
Sediment/ 
Hinge Point 
Atmospheric 
Aerosols 
Atmospheric 
Aerosols 
Used with the 565 nm band for determining color boundaries, 
chlorophyll concentration, and diffuse attenuation coef- 
ficient (k). 
Used with the 565 nm band for mapping color and chlorophyll 
concentration in coastal waters. 
Used as a hinge point for determining chlorophyll, pigments, 
water optical properties (k), and measuring suspended 
sediments. 
Used to correct above bands for atmospheric effects. This 
band is not the best for aerosols since total radiance at the 
sensor is not zero in coastal waters, but it is compatible 
with CZCS processing techniques. 
Used to correct first three bands for the atmosphere. Better 
than 665 nm, if the sensitivity of the band is set to monitor 
aerosols and not land/water boundaries. 
NOTE: The band centered at 765 nm actually consists of two bands, 745 to 759 nm and 770 to 785 nm, 
illuminating a single detector, but blocked to avoid interference by oxygen absorption near 765 nm. 
405 nm Band. A number of panel members proceeding to lower wavelengths accentuates 
suggested including a band at 405 nm for the the difference between gelbstoffe and chlorophyll 
primary purpose of observing the strong blue ab- concentrations. It is impossible to determine 
sorption by gelbstoffe.4 
sorption by chlorophyll is near 435 nm and 
Since the maximum ab- when gelbstoffe absorption is affecting pigment- 
concentration estimates with band-ratio tech- 
gelbstoffe absorption increases almost exponen- niques using the CZCS suite of bands. A 405 nm 
tially with decreasing wavelength in this region, band would provide this information, at least at 
aes low pigment concentrations where reflectance at 
“tis important to note that gelbstoffe (yellow substance or 405 nm is still measurable. 
blue absorbing matter) is not synonomous with what is com- However, good atmospheric correction for 
monly referred to in the literature as dissolved organic matter this band will be critical for use of the data and 
(DOM). Gelbstoffe is a variable, generally small, component 
of the total DOM that is strongly absorbing in the violet and 
will be very difficult to achieve. In addition, de- 
blue and is comprised, classically, of highly stable humic and tector performance in this region is poor, and the 
fulvic acids from terrestrial plant decomposition found in riv- sensor's signal-to-noise ratio (SNR) performance 
ers and swamps. On occasion, decomposing phytoplankton is likely to be significantly lower in this band than 
blooms also produce optically similar compounds. The DOM in other bands. Also, polarization sensitivity would 
released extracellularly from plankton (considered by some 
to be a major pathway of carbon cycling in the ocean) gen- 
be worst in this band. For these reasons, the 
erally shows little absorbance in the visible. Hence, the 405 concensus of the panels was to select a different 
nm band cannot be used to estimate DOM. 
region for the sixth band. 
39 
