BackForwardInstrument:  WindSat 

Instrument details
Acronym WindSat
Full name WindSat
Purpose Demonstration of sea surface wind vector observation by polarimetric passive radiometry
Short description 5 frequencies, 22-channel MW radiometer; three channels with full polarimetric capability [see detailed characteristics below]
Background New development
Scanning Technique Conical: 50-55° zenith angle, swath 1000 km – Scan rate: 31.6 scan/min = 12.5 km/scan
Resolution Changing with frequency, consistent with antenna diameters of 1.83 m
Coverage / Cycle Global in 1.5 days
Mass 307 kg Power 311 W Data Rate 256 kbps

 

Providing Agency DoD
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2003 to ≥2017
Last update: 2014-07-23
Detailed characteristics
Central frequency (GHz) Bandwidth (MHz) Polarisations (*) NEΔT IFOV Pixel
6.8 125 V, H 0.48 K 39x71 km 25.0x12.5 km
10.7 300 V, H, P, M, L, R 0.37 K 25x38 km 25.0x12.5 km
18.7 750 V, H, P, M, L, R 0.39 K 15x24 km 12.5x12.5 km
23.8 500 V, H 0.55 K 20x30 km 12.5x12.5 km
37.0 2000 V, H, P, M, L, R 0.45 K 8x13 km 6.25x12.5 km

(*)   Polarisations: H = horizontal, V = vertical, P = + 45°, M = - 45°, L = left-hand circular, R = right-hand circular

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
  • Sea surface temperature
  • Sea-ice cover
  • Wind speed over the surface (horizontal)
  • Wind vector over the surface (horizontal)
Secondary mission objectives
  • Biomass
Show allShow fewer
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 and 37 GHz, with high spatial resolution
Biomass4 - fairIndex only.. Coarse spatial resolution.Derived from differential effect of vegetation across MW frequencies around 7, 10 and 19 GHz
Cloud liquid water (CLW)5 - marginalNo specific limitation.MW channels around 37 GHz
Cloud liquid water (CLW) total column4 - fairNo specific limitation.MW channels around 37 GHz
Land surface temperature3 - highCoarse spatial resolution.MW channels with more frequencies around 7 and 10 GHz to reduce sensitivity to radio-frequency interferences
Long-wave Earth surface emissivity4 - fairLong time series needed.MW channels around 7, 10, 19 and 37 GHz. Emissivity across this MW range inferred by statistical analysis
Precipitation intensity at surface (liquid or solid)3 - highNo specific limitation.MW channels around 10, 19, 23, and 37 GHz. High spatial resolution consistent with the scale of precipitation
Sea surface temperature2 - very highNo specific limitation.MW channels with more frequencies around 7 and 10 GHz to reduce sensitivity to radio-frequency interferences
Sea-ice cover2 - very highNo specific limitation.MW channels around 7, 10, 19 and 37 GHz, with high spatial resolution for accurate contour detection
Sea-ice type5 - marginalNo specific limitation.MW channels around 7, 10, 19 and 37 GHz. Type interpreted as age/roughness
Snow cover3 - highCoarse spatial resolution.MW channels around 19 and 37 GHz with high resolution closer to the scale of snow fields
Snow status (wet/dry)3 - highCoarse spatial resolution.MW channels around 19 and 37 GHz with high resolution closer to the scale of snow fields
Snow water equivalent4 - fairCoarse spatial resolution.. Ground stations network needed.MW channels around 19 and 37 GHz with high resolution closer to the scale of snow fields
Soil moisture (in the roots region)4 - fairCoarse spatial resolution.. Affected by vegetation.MW channels around 7 GHz. Assimilation process required
Soil moisture at surface3 - highCoarse spatial resolution.. Affected by vegetation.MW channels around 7 and 10 GHz
Integrated Water Vapour (IWV)1 - primaryNo specific limitation.Use of water vapour band around 23 GHz with dual polarisation. High resolution useful for tomography
Wind speed over the surface (horizontal)2 - very highOver sea only.MW channels around 7, 10, 19 and 37 GHz
Wind vector over the surface (horizontal)3 - highOver sea only.MW channels for 3 or 4 Stokes parameters at frequencies around 10, 19 and 37 GHz