As might "be expected from the name, the MRIR's resolution was 

 much coarser than that of the SRIR. For example, at an altitude of 

 1,100 km. (595 nm.)> "the 10 to 11 micron channel had a resolution of 

 55 km. (30 nm.) at zero nadir angle. Recent work has shown that 

 despite the MRIR's lower resolution It may he posslhle to derive such 

 things as sea siorface temperature from the data. If the region Is 

 cloud-free and the projection scale used is approximately It 5 million 

 or greater. 



The Klmbtis satellites circled the glohe In a polar orhlt, their 

 sensors constantly oriented to the earth and their orhlts timed to 

 occur always at approximately local midday on the earth's lighted side 

 and at local midnight on the earth's dark side. Thvis, each point on 

 the earth's surface was viewed at least twice a day hy the satellite. 

 Overlaps in the satellite coverage increased toward higher latitudes 

 with each of the poles helng viewed fourteen times in twenty-four hours, 



MIDNIGHT 



POLAR ORBIT FOR 

 LATITUDINAL 

 COVERAGE 



SUN-SYNCHRONOUS ORBIT 



SUN 



MIDDAY 



EARTH ROTATION FOR 

 LONGITUDINAL COVERAGE 



Figure 4 The Nimbus midday-midnight sun-synchronous orbit 



10 



