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Solar radiation and its variation in time


In order to assess the variability of the solar radiation, the record of determinations of the total and spectral solar irradiance of the last 15 years is analysed. Although the datapoints for the period before 1969 suggest a slight decrease, the uncertainties of these determinations are too large to render this statement significant. Together with the results of the following period (1969–1980) which show that within the uncertainty no change is detectable, it can be concluded, that the solar constant has not changed during the last 15 years. The same result is found from the spectral distribution record, though not as conclusive as for the solar constant, due to the much larger uncertainties of the spectral data.

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Proceedings of the 14th ESLAB Symposium on Physics of Solar Variations, 16–19 September 1980, Scheveningen, The Netherlands.

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Fröhlich, C., Brusa, R.W. Solar radiation and its variation in time. Sol Phys 74, 209–215 (1981).

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  • Radiation
  • Solar Radiation
  • Spectral Data
  • Large Uncertainty
  • Solar Irradiance