The CZCS has six spectral bands, five sensing backscattered solar 

 radiance and one sensing emitted thermal radiance. Table 1 shows the 

 center wavelengths, the spectral bandwidths, and the minimum signal-to- 

 noise ratio specified for the instrument at the most sensitive gain setting; 

 that is, the gain setting that would be used for the darkest targets. The first 

 four channels were selected to cover specific absorption bands and the so- 

 called hinge point. These channels are meant to look at water only and 

 saturate when the field of view is over land surfaces and clouds. The 

 spectral response of Channels 1 through 5 is illustrated in Figure 1. 



Figure 1. CZCS Spectral Response for Channels 1-5. 



NANOMETERS (nin) WAVELENGTH (/\) 

 J L 



420 



460 



500 



540 



580 



620 



660 



700 



740 



780 



820 



Channel 5 has the same spectral response as Channel 6 of the Landsat 

 multi-spectral scanner series. The gain of Channel 5 is fixed and set to 

 produce the same percentage of maximum signal over land targets as the 

 Landsat Channel 6. However, the actual radiance for saturation is higher 

 since the Nimbus-7 spacecraft crosses the Equator at high noon whereas 

 Landsat crosses the Equator at 9:30 a.m. local time. 



The CZCS Channel 6 ( 10.5 to 12.5 /nm) measures equivalent blackbody 

 temperature as seen by the sensor with a moist equivalent temperature 

 difference of less than 0.35° K at 270° K. Atmospheric interference with 

 this channel, principally from weak water vapor absorption in the 10.5 to 



