The second infrared sensor — Medlim Resolution Infrared 

 Radiometer, or MRIR — was a five-channel scanning radiometer designed 

 to measure electromagnetic radiation emitted and reflected In spectral 

 hands from the earth and its atmosphere » (The range of one of the five 

 channels of the I^IRIR actually extended slightly into the vlslhle 

 portion of the spectrum)* A variety of Information may he obtained 

 from each of the channels as veil as from a combination of channels 

 (Table 3). 



Table 3. The Five Channels of the Wlmbus 2 MRIR 



Channel 1 - 6.4 to 6.9 microns 

 Covers the 6.7 micron vater vapor absorption band. Provides 

 information on water vapor distribution in the upper tropofe,here and, 

 in conjunction with other channels, provides relative humidities at 

 these altitudes . 



Channel 2 - 10 to 11 microns 

 Operates day and night in an atmospheric "window" to give 

 measurements of surface or near-surface temperatures in clear sky 

 areas. Also provides cloud cover and cloud height information. 



Channel 3 - 1^ to 16 microns 

 Centered about the strong absorption band of CO2 at I5 microns, 

 this channel measures radiation which emanates primarily from the 

 stratosphere. Prime importance is to follow seasonal stratospheric 

 temperature changes. 



Channel 4 - 5 to 30 microns 

 Measures the emitted thermal Infrared energy and, in conjunction 

 with the reflected solar radiation channel, furnishes data on the heat 

 budget of the planet. 



Channel 5 - 0*2 to k.O microns 

 Covers more than 99^ of the energy in the solar spectrum. Gives 

 information on the intensity of reflected solar energy from the earth 

 and its atmosphere. 



