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Solar Constant

Total Solar Irradiance (TSI) has been monitored with absolute radiometerssince 1978 onboard five different satellites:
  • Hickey-Frieden (HF) radiometer onboard the NIMBUS-7 spacecraft:16.11.78 - 24.01.93
  • ACRIM I onboard the Solar Maximum Mission (SMM) spacecraft: 14.02.80- 01.06.89
  • Absolute radiometer onboard the Earth Radiation Budget Satellite (ERBS):since 25.10.84
  • ACRIM II onboard the Upper Atmosphere Research Satellite (UARS):since October 1991
  • DIARAD and PMO6-V absolute radiometers of VIRGO onboard the SOHOspacecraft: since 18.01.96
Each time series was corrected for sensitivity changes and operationalinfluences as described in Fröhlich and Lean (1998) and shown below.

Total Solar Irradiance Data

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 Image: Postscript
 
In order to compose a uniform TSI time series, the different time series have to be homogenized and adjusted to a common scale (Space Absolute Radiometric Reference). The result is shown in the Figure below.

Total Solar Irradiance Data

Click here to get a full size view

Image: 
Postscript | PDF

 ASCII: Data File
 
Reference: Fröhlich, C. and Lean, J.: 1998, Total solar irradiance variations: The construction of a composite and its comparison with models, in F. L. Deubner (ed.), IAU Symposium 185: New Eyes to See Inside the Sun and Stars, Kluwer Academic Publ., Dortrecht, The Netherlands, pp. 89-102, 1998. (preprint as postscript file).

See also:
>>The VIRGO homepage
>>VIRGO Total Solar Irradiance
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