BackForwardInstrument:  TMI  

Instrument details
Acronym TMI
Full name TRMM Microwave Imager
Purpose Multi-purpose imagery, with emphasis on precipitation
Short description 5 frequencies / 9 channels [see detailed characteristics below]
Background New development
Scanning Technique Conical: 53° zenith angle; useful swath: 760 km - Scan rate: 31.6 scan/min = 13.7 km/scan
Resolution Changing with frequency, consistent with an antenna diameter of  61 x 66 cm
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 65 kg Power 50 W Data Rate 8.8 kbps

 

Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1998 to 2015
Last update: 2022-07-25
Detailed characteristics

No.

Central frequency (GHz)

Bandwidth (MHz)

Polarisation

NEΔT

IFOV

Pixel

1

10.65

100

V

0.6 K

37x63 km

9.2x13.7 km

2

10.65

100

H

0.6 K

37x63 km

9.2x13.7 km

3

19.35

500

V

0.7 K

18x30 km

9.2x13.7 km

4

19.35

500

H

0.7 K

18x30 km

9.2x13.7 km

5

21.3

200

V

0.9 K

18x23 km

9,2x13.7 km

6

37.0

2000

V

0.4 K

9x16 km

9.2x13.7 km

7

37.0

2000

H

0.4 K

9x16 km

9.2x13.7 km

8

85.5

3000

V

0.7 K

5x7 km

4.6x13.7 km

9

85.5

3000

H

0.7 K

5x7 km

4.6x13.7 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
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)
  • 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.
VariableRelevance for measuring this variableOperational limitationsExplanation
Accumulated precipitation2 - very highPoor 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)3 - highNo specific limitation.MW channels around 37 and 90 GHz
Cloud liquid water (CLW) total column3 - highNo specific limitation.MW channels around 37 and 90 GHz
Land surface temperature5 - marginalCoarse spatial resolution.MW channels around 10 GHz
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
Precipitation intensity at surface (liquid or solid)*2 - very highNo 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
Sea surface temperature5 - marginalWarm temperature only.MW channels around 10 GHz
Snow cover2 - very highCoarse 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 status (wet/dry)1 - primaryCoarse 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 equivalent1 - primaryCoarse 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
Soil moisture at surface3 - highCoarse spatial resolution.. Strongly affected by vegetation.MW channels around 10 GHz
Integrated Water Vapour (IWV)3 - highOver sea only.MW channel(s) in the water vapour band around 23 GHz
Wind speed (near surface)*3 - highOver sea only.MW channels around 10, 19 and 37 GHz