Another instrument onboard Nimbus-5 was the first microwave sounding device, Nimbus Experimental Microwave Spectrometer (NEMS), a nadir-viewing 5-channel instrument (Staelin et al. 1973). NEMS demonstrated the capability to probe through clouds, even dense overcast.

Good agreement between ITPR, NEMS, and radiosonde data was achieved. It was found however, that the best results were achieved from an amalgamation of infrared and microwave radiance data in the temperature profile inversion process thereby providing the maximum available thermal information, regardless of cloud conditions (Smith et al. 1974b).