WMO OSCAR | Details for Instrument GMI (core)

No JavaScript detected
Usage of this Website will be severly limited without JavaScript. Please enable JavaScript in your Browser.

Instrument: GMI (core)

Instrument details

Acronym	GMI (core)
Full name	GPM Microwave Imager
Purpose	Multi-purpose imager, with emphasis on precipitation
Short description	8 frequencies / 13 channels [see detailed characteristics below]
Background	Evolution of TMI on TRMM
Scanning Technique	Conical: 53° zenith angle; useful swath: 850 km - Scan rate: 32 scan/min = 13.4 km/scan
Resolution	Changing with frequency, consistent with an antenna diameter of 1.2 m (only partially illuminated at higher frequencies)
Coverage / Cycle	Near-global coverage in 2 days; high latitudes (> 70°) not covered.
Mass	150 kg	Power	140 W	Data Rate	25 kbps

Providing Agency	NASA
Instrument Maturity	Backed by strong heritage
Utilization Period:	2014 to 2030
Last update:	2021-06-15

Detailed characteristics

No.	Central frequency (GHz)	Bandwidth (MHz)	Polarisation	NEΔT	IFOV	Pixel
1	10.65	100	V	0.96 K	19x32 km	12x13.4 km
2	10.65	100	H	0.96 K	19x32 km	12x13.4 km
3	18.7	200	V	0.84 K	11x18 km	6.0x13.4 km
4	18.7	200	H	0.84 K	11x18 km	6.0x13.4 km
5	23.8	400	V	1.05 K	9.2x15 km	6.0x13.4 km
6	36.5	1000	V	0.65 K	8.6x14 km	6.0x13.4 km
7	36.5	1000	H	0.65 K	8.6x14 km	6.0x13.4 km
8	89.0	6000	V	0.57 K	4.4x7.2 km	3.0x13.4 km
9	89.0	6000	H	0.57 K	4.4x7.2 km	3.0x13.4 km
10	166.5	4000	V	1.5 K	4.4x7.2 km	3.0x13.4 km
11	166.5	4000	H	1.5 K	4.4x7.2 km	3.0x13.4 km
13	183.31 ± 7	2000	V	1.5 K	4.4x7.2 km	3.0x13.4 km
12	183.31 ± 3	2000	V	1.5 K	4.4x7.2 km	3.0x13.4 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

Global Precipitation Measurement mission (NASA)
- GPM Core Observatory (see instrument status) May 2014 - 2030

Instrument classification

Earth observation instrument
Passive microwave radiometer
Conical 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

Precipitation intensity at surface (liquid or solid)
Sea-ice cover
Wind speed (near surface)

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.

Search:

Variable	Relevance for measuring this variable	Operational limitations	Explanation
Snow status (wet/dry)	1 - primary	Coarse spatial resolution.	MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow. High resolution closer to the scale of snow fields
Snow water equivalent	1 - primary	Coarse spatial resolution.. Ground stations network needed.	MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow. High resolution closer to the scale of snow fields
Integrated Water Vapour (IWV)	1 - primary	No specific limitation.	MW channel(s) in the water vapour bands around 23 and 183 GHz
Accumulated precipitation	2 - very high	Poor time sampling.. Time sampling to be interpolated by GEO.	MW channels around 10, 19, 23, 37 and 90 GHz, with high spatial resolution
Cloud liquid water (CLW)	2 - very high	No specific limitation.	MW channels around 37 and 90 GHz, and in 183 GHz band
Cloud liquid water (CLW) total column	2 - very high	No specific limitation.	MW channels around 37 and 90 GHz, and in 183 GHz band
Precipitation intensity at surface (liquid or solid)*	2 - very high	No specific limitation.	MW channels around 10, 19, 23, 37 and 90 GHz, to cover sea and land, heavy and light precipitation. High spatial resolution consistent with the scale of precipitation
Snow cover	2 - very high	Coarse spatial resolution.	MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow . High resolution closer to the scale of snow fields
Sea-ice cover*	2 - very high	No specific limitation.	MW channels around 10, 19, 37 and 90 GHz, with high spatial resolution for accurate contour detection
Soil moisture at surface	3 - high	Coarse spatial resolution.. Strongly affected by vegetation.	MW channels around 10 GHz
Wind speed (near surface)*	3 - high	Over sea only.	MW channels around 10, 19 and 37 GHz
Long-wave Earth surface emissivity	4 - fair	Long time series needed.	MW channels around 10, 19, 37 and 90 GHz. Emissivity across this MW range inferred by statistical analysis
Sea-ice type	4 - fair	No specific limitation.	MW channels around 10, 19, 37 and 90 GHz. Type interpreted as age/roughness
Land surface temperature	5 - marginal	Coarse spatial resolution.	MW channels around 10 GHz
Sea surface temperature	5 - marginal	Warm temperature only.	MW channels around 10 GHz

Showing 1 to 15 of 15 entries