HRIR and MRIR data were processed for display In two ways: a 

 digital form for quantitative analysis; and an Imagery form, similar 

 to television pictures, for comparative studies. Useful HRIR digital 

 data were limited to those data collected during the night since the 

 daytime meaaureEents had reflected solar radiation added to the earth's 

 Infrared emission (hecause of the attitude of the satellite and the 

 angle of Incidence of the sun's rays, the satellite's sun shields were 

 sometimes Ineffective at high latitudes on the night side and the HRIR 

 data were occasionally contaminated). 



Infrared imagery was found to "be usalDle from Taoth the day and 

 night passage since the pictorial Information was dlscernahle despite 

 the solar radiation. The use of HRIR imagery of Icefields during the 

 polar night has shown great promise. For example, HRIR and AVCS 

 (Advanced Vidlcon Camera System—see Section h) pictures of the 

 Weddell Sea during daylight hours show the position of a large iceberg 

 in what may he either open water or thin ice. 



In addition to the delineation of ice regions, HRIR Imagery is 

 useful in getting a visual survey of the cloud dlstrlhutlon. The 

 Nimbus HRIR catalogues are presented as strip mosaics of HRIR Imagery. 

 Thus, the amount of HEIR data avallahle for an area and a time can he 

 assessed quickly hy examining these visual presentations. 



The areal coverage of the surface of the oceans hy the HRIR and 

 MRIR data was limited hy the amount of cloud cover. This interruption 

 hy clouds is normally obvious in the data when the cloud temperatures 

 are low. However, because the HRIR data were collected at night and 



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