The ability of the GOES-8 sounder to retrieve accurate temperature profiles of the atmosphere is apparent in this comparison of a GOES-8 sounder profile with VAS and radiosonde profiles. All three profiles are coincident. The GOES-8 temperature retrieval is generally in good agreement with the radiosonde profile and is superior to the VAS retrieval.
In addition to the advantage the GOES-8 sounder has over the VAS with respect to point source retrievals, the GOES-8 sounder also outperforms the VAS when comparing fields of retrieved values produced by the two sounders. This is evident when comparing GOES-8 and VAS retrievals of 400 hPa dewpoint temperature valid at 12 UTC on 7 October 1994. First, the striping present for the VAS, due to the part-time sounding coverage, is eliminated for the GOES-8 with the full-time operational sounder. The GOES-8 sounder generates more retrievals than does the VAS allowing a better delineation of moisture in and around clouds. The elliptical dry (yellow color) region on the GOES-8 side is much sharper than the same diffuse area on the VAS side.
The GOES-8 sounder also retrieves many more profiles of temperature and moisture in clear or partly clear situations than sounders on polar-orbiting platforms. A comparison of retrieved 700 hPa temperatures at 14 UTC on 7 July 1994 for the GOES-8 sounder and the TOVS demonstrates this point. The GOES-8 sounder retrieves with greater density and coverage than does the TOVS. The TOVS holds a retrieval advantage, only in regions of thin clouds, due to microwave capabilities. However the TOVS can only sound an area twice a day while the GOES-8 sounder is able to provide hourly retrievals.