3. Infrared Radiometer /imagery 



Temperature Information on the ocean's surface may be obtained by 

 using infrared sensors to measure the water's equivalent blackbody 

 temperature a To date, only the Nimbus satellites have provided 

 infrared data with the detail necessary for oceanographic work. Two 

 infrared sensors were used aboard these satellites. 



The one most useful oceanographlcally was a scanning radiometer -- 

 High Resolution Infrared Radiometer or HKER — operating in the 3<.k to 

 4.2 micron atmospheric "window" region. At zero nadir angle (i.e. 

 directly below the satellite) the Nimbus 2 HRIR at an altitude of 

 1,100 knio (595 nm.) had a resolution of 9 km. (5 nm. ) 



1.0 



0.8 



CO 



t 0.6 



0.4 



0.2 



REPRESENTATIVE ABSORPTION 



FROM GROUND TO TOP OF 

 ATMOSPHERE 



\ EFFECTIVE SPECTRAL i 

 > RESPONSE- 



\ 



\ 



\ 



\ 



\ 



WATER \ 

 VAPOR \ 



Figure 3 



3.2 3.4 3.6 3.8 4.0 4.2 4.4 

 WAVE LENGTH (MICRONS) 



The Nimbus HRIR atmospheric "window" 



