BackForwardInstrument:  HRDI 

Instrument details
Acronym HRDI
Full name High-Resolution Doppler Imager
Purpose Mapping of atmospheric vector winds in the upper atmosphere
Short description Observation of the Doppler shifts of spectral lines of molecular and ionized oxygen. 13 bands of width 0.5 cm-1 in the range 557-776 nm with a spectral resolution of 0.05 cm-1. Absorption lines in the upper troposphere and mesosphere. emission lines (night and day) in the mesosphere and thermosphere
Background New development
Scanning Technique Limb sounding of the regions below 45 km and above 60 km
Resolution Vertical: 3 km; horizontal: 300 km along-view
Coverage / Cycle Global (except high latitudes) for cells of 300 km side in 2 or 3 days
Mass Power Data Rate 4.75 kbps


Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1991 to 2005
Last update: 2017-03-29
Detailed characteristics
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
  • Limb sounders
  • Limb sounder
WIGOS Subcomponents
  • Subcomponent 2
  • UV/VIS/NIR/IR/MW limb sounders
  • UV/VIS/NIR/IR/MW scanning limb sounder
Mission objectives
Primary mission objectives
  • Wind (horizontal)
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
Atmospheric temperature4 - fairLimited to high atmosphere.NIR limb sounding by emission in the O2 A-band around 760 nm. Used for the thermosphere
Wind (horizontal)*4 - fairLimited to high atmosphere.VIS and NIR very-high resolution limb spectrometry. Doppler analysis of oxygen emission lines