The Sounder - Profile Retrievals

• Vertical temperature profiles from sounder radiance measurements are produced at 40 pressure levels from 1000 to 0.1 mb
• Also, estimates of surface emissivity, cloud-top pressure, and cloud amount are obtained as by-products.
• The retrieval begins with a first-guess temperature profile that is obtained from a space-time interpolation of fields provided by NWS forecast models.
• Hourly surface observations and sea surface temperature from AVHRR help provide surface boundary information.
• Soundings are produced from a 5 x 5 array of FOVs whenever nine or more FOVs are determined to be either clear or contaminated by "low cloud."
• Here is an example of a satellite-derived sounding compared to an NWS sounding

• Vertical moisture (mixing ratio--hence, specific humidity) profiles are obtained in the simultaneous retrieval and are provided at the same levels as temperature up to 300 mb.

see also:

http://www.meted.ucar.edu/satmet/goessounder/

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