BackForwardInstrument:  GMI (constellation) 

Instrument details
Acronym GMI (constellation)
Full name GPM Microwave Imager
Purpose Multi-purpose imager, with emphasis on precipitation
Short description 8 frequencies / 13 channels [see detailed characteristics below]
Background Similar to GMI on GPM-core but operating in higher altitude and low-inclination orbit
Scanning Technique Conical: 53° zenith angle; useful swath: 1300 km - Scan rate: 32 scan/min = 12.8 km/scan
Resolution Changing with frequency, consistent with an antenna diameter of  1.2 m (only partially illuminated at higher frequencies)
Coverage / Cycle Intertropical coverage, several sequences of passes at ~ 100-min intervals with longer gaps once or twice per day; more regular coverage at 15°N and 15°S
Mass 150 kg Power 140 W Data Rate 25 kbps

 

Providing Agency NASA
Instrument Maturity Backed by strong heritage
Utilization Period: TBD
Last update: 2017-03-29
Detailed characteristics
Central frequency (GHz) Bandwidth (MHz) Polarisations NEΔT IFOV Pixel
10.65 100 V, H 0.96 K 30x50 km 24x12.8 km
18.7 200 V, H 0.84 K 17x29 km 12x12.8 km
23.8 400 V 1.05 K 14x24 km 12x12.8 km
36.5 1000 V, H 0.65 K 13x22 km 6.0x12.8 km
89.0 6000 V, H 0.87 K 6.9x11 km 3.0x12.8 km
166.0 3000 V, H 1.5 K 6.9x11 km 3.0x12.8 km
183.31 ± 3 3500 V 1.5 K 6.9x11 km 3.0x12.8 km
183.31 ± 7 4500 V 1.5 K 6.9x11 km 3.0x12.8 km
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
  • Conical scanning microwave radiometer
Mission objectives
Primary mission objectives
  • Precipitation intensity at surface (liquid or solid)
  • Wind speed (near surface)
Secondary mission objectives
  • Cloud liquid water (CLW) total column
  • Integrated Water Vapour (IWV)
  • Sea surface temperature
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Tentative 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
VariableRelevance for measuring this variableOperational limitationsExplanation
Accumulated precipitation (over 24 h)4 - fairPoor time sampling.. Time sampling to be interpolated by GEO.MW channels around 10, 19, 23, 37 and 90 GHz
Wind speed (near surface)3 - highOver sea only.MW channels around 10, 19 and 37 GHz
Integrated Water Vapour (IWV)1 - primaryNo specific limitation.MW channel(s) in the water vapour bands around 23 and 183 GHz
Sea surface temperature5 - marginalWarm temperature only.MW channels around 10 GHz
Cloud liquid water (CLW)2 - very highNo specific limitation.MW channels around 37 and 90 GHz, and in 183 GHz band
Cloud liquid water (CLW) total column2 - very highNo specific limitation.MW channels around 37 and 90 GHz, and in 183 GHz band
Precipitation intensity at surface (liquid or solid)4 - fairNo specific limitation.MW channels around 10, 19, 23, 37 and 90 GHz, to cover sea and land, heavy and light precipitation
Long-wave Earth surface emissivity4 - fairLong time series needed.MW channels around 10, 19, 37 and 90 GHz. Emissivity across this MW range inferred by statistical analysis
Soil moisture at surface3 - highCoarse spatial resolution.. Strongly affected by vegetation.MW channels around 10 GHz
Land surface temperature5 - marginalCoarse spatial resolution.MW channels around 10 GHz
Snow status (wet/dry)2 - very highCoarse spatial resolution.MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow
Snow cover3 - highCoarse spatial resolution.MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow
Snow water equivalent2 - very highCoarse spatial resolution.. Ground stations network needed.MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow