fine spectral resolution microwave sounders now 25 viable as replacements to the current operational 26 instruments. This study demonstrates that retrievals 27 of temperature and moisture soundings can be 28 improved by as much as 50% when 60-80 29 appropriately chosen pseudo-channels are employed. 30 While the current simulations were limited to cloud 31 free oceans, perhaps even greater benefits can be 32 realized over land and cloud conditions where 33 additional channels can help constrain the surface and 34 clouds. The study also demonstrated the advantages 35 of hyperspectral sensors as a way to detect Radio 36 Frequency Interference (RFI) in the few Kelvin 37 range, as well as its ability to improve intercalibration 38 efforts due to its ability to match frequency response 39 functions of target sensors. 40 41 42 43 Temperature and humidity soundings form the 44 bedrock of modern data assimilation due to their 45 ability to directly constrain the atmospheric state 46 variables. The primary sources of global sounding 47 data are satellite infrared (IR) and passive microwave 48 sensors, although radio occultation [1] has also had 49 success in constraining numerical models. While IR 50 sensors dominated the very early instrument suites, 51 and have very good vertical resolution, they are 52 limited to cloud-free scenes. To overcome this 53 limitation, microwave sensors were deployed. While 54 their weighting functions and subsequent vertical 55 resolution are much broader than their IR 56 counterparts, their ability to penetrate clouds and 57 work in all weather conditions make them perhaps 58 the most useful instruments for constraining 59 Numerical Weather Prediction (NWP) models (e.g. 60 [2]).