BackForwardInstrument:  MADRAS 

Instrument details
Acronym MADRAS
Full name Microwave Analysis & Detection of Rain & Atmospheric Structures
Purpose Contribution to the Global Precipitation Measurement mission (GPM)
Short description 5 frequencies / 9 channels [see detailed characteristics below]
Background New development. Joint development by ISRO and CNES.
Scanning Technique Conical: 56° zenith angle; swath: 1700 km - Scan rate: 24.6 scan/min = 16 km/scan
Resolution IFOV ranging from 6 km at 157 GHz to 50 km at 18.7 GHz, consistent with a 65-cm antenna diameter
Coverage / Cycle Intertropical coverage 2 to 5 times/day depending on latitude (best coverage at 15°N and 15°S)
Mass 162 kg Power 153 W Data Rate 37 kbps

 

Providing Agency ISRO
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2013-01-15 to 2013-09-24
Last update: 2019-11-14
Detailed characteristics
No. Central frequency (GHz) Bandwidth (MHz) Polarisations NEΔT IFOV Pixel
1 18.7 200 V, H 0.43 K 40 x 60 km 40 x16 km
2 23.8 400 V 0.44  K 31 x 47 km 40 x16 km
3 36.5 1000 V, H 0.36 K 20 x 31 km 40 x16 km
4 89.0 1700 V, H 0.42 K 10 x15 km 10 x16 km
5 157.0 1700 V, H 1.13 K 6 x 9 km 6 x16 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)
Secondary mission objectives
  • Cloud liquid water (CLW) total column
  • Integrated Water Vapour (IWV)
  • Snow cover
  • Snow status (wet/dry)
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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 19, 23, 37 and 90 GHz
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
Long-wave Earth surface emissivity5 - marginalLong time series needed.MW channels around 19, 37 and 90 GHz. Emissivity across this MW range inferred by statistical analysis
Precipitation intensity at surface (liquid or solid)4 - fairNo specific limitation.MW channels around 19, 23, 37 and 90 GHz; 90 GHz very important over land
Snow cover3 - highCoarse spatial resolution.MW channels around 19, 37 and 90 GHz. Higher frequencies less sensitive to emissivity from ground under snow
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 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
Integrated Water Vapour (IWV)3 - highOver sea only.MW channel(s) in the water vapour band around 23 GHz
Wind speed (near surface)4 - fairOver sea only.MW channels around 19 and 37 GHz