BackForwardInstrument:  SAPHIR 

Instrument details
Acronym SAPHIR
Full name Sondeur Atmospherique du Profil d’Humidite Intertropicale par Radiometrie
Purpose Humidity sounding in nearly-all-weather conditions.  Also precipitation
Short description 6 channels in the 183 GHz band [see detailed characteristics below]
Background New development
Scanning Technique Cross-track: 130 steps of 10 km s.s.p., swath 1700 km - Along-track: one 10-km lines every 1.6 s
Resolution 10 km IFOV
Coverage / Cycle Intertropical coverage 2 to 5 times/day depending on latitude (best coverage at 15°N and 15°S)
Mass 18 kg Power 30 W Data Rate 1.5 kbps

 

Providing Agency CNES
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2012 to 2022
Last update: 2021-06-17
Detailed characteristics

No.

Central frequency (GHz)

Bandwidth (MHz)

Polarisation

NEΔT

6

183.31 ± 11

2000

H

1.0 K

5

183.31 ± 6.6

1200

H

1.3 K

4

183.31 ± 4.2

700

H

1.3 K

3

183.31 ± 2.7

500

H

1.5 K

2

183.31 ± 1.1

350

H

1.5 K

1

183.31 ± 0.2

200

H

2.0 K
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Earth observation instrument
  • Passive microwave radiometer
  • Cross-track, special or non-scanning microwave radiometer
WIGOS Subcomponents
  • Subcomponent 1
  • MW sounder and imagery in inclined orbits
  • MW sounder and imager in inclined orbits
Mission objectives
Primary mission objectives
  • Specific humidity
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Downward long-wave irradiance at Earth surface5 - marginalHighly indirect.MW channels in 183 GHz band to account for downward cloud radiation
Precipitation intensity at surface (liquid or solid)5 - marginalNo specific limitation.MW channels in the 183 GHz band. Suitable for solid precipitation over sea and land, Insensitive to surface emissivity
Specific humidity*3 - highCoarse vertical resolution.MW channels in the 183 GHz band
Integrated Water Vapour (IWV)2 - very highNo specific limitation.MW channels in the water vapour band around 183 GHz
Upward long-wave irradiance at Earth surface5 - marginalHighly indirect.MW channels is the 183 GHz band to infer the impact of clouds on the upward LW radiation