OSCAR

Each instrument is assigned with a 5-step rating, evaluated as a blend of several elements such as the uncertainty, the vertical resolution, and the frequency and spatial resolution of the retrieved measurement in comparison with the space-time variability of the geophysical parameter.  For this particular Variable, the rating is driven by:

• the spectral interval used to infer the temperature from the emission of CO₂ (in IR) or O₂ (in MW);
• the spectral resolution or the number of channels;
• the observing technique (cross-nadir sounding, limb sounding, radio-occultation);
• the orbit (GEO or LEO).

RATING CRITERIA:

1

• TIR and/or MWIR high-resolution spectrometer in LEO
• TIR and/or MWIR medium-resolution spectrometer in GEO
• Cluster of radio-occultation sounders
• MW radiometer with >=10 channels in the 54 GHz band in LEO

2

• TIR and/or MWIR medium or low resolution spectrometer  in LEO
• TIR and/or MWIR non-scanning spectrometer in LEO
• Radio-occultation sounder tracking >=2 GNSS systems in setting and/or rising phase
• MW radiometer with < 10 channels in the 54 and/or 118 GHz band in LEO

3

• TIR and/or MWIR radiometer with several channels in GEO or LEO
• Radio-occultation sounder tracking <2 GNSS systems in setting and/or rising phase
• MW radiometer with < 5 channels in the 54 and/or 118 GH band in LEO

4

• TIR and/or MWIR radiometer with very few channels in GEO or LEO
• Radio-occultation sounder with omni-directional antenna
• Limb-sounding spectrometer by mechanical or electronical scanning, including Mm-submm

5

• Limb-sounding spectrometer by star occultation
• Limb-sounding spectrometer by solar occultation