Total solar irradiance during the last three cycles: Uncertainities of the long-term behaviour
Abstract
Since November 1978 a set of total solar irradiance (TSI) measurements from space is available, yielding a time series of 30 years. Presently, there are three TSI composites available, called PMOD, ACRIM and IRMB, which are all constructed from the same original data, but use different procedures to correct for long-term sensitivity changes. The PMOD composite is the only one which also corrects the early HF data for degradation and thus allows to compare all three cycles. This composite can now be used to assess the uncertainty of the long-term behaviour of TSI by comparison with independent measurements from ERBE and for the cycle 23 which is based on VIRGO data also with ACRIM-II on UARS, ACRIM-III on ACRIM-Sat and TIM on SORCE. Also different reconstructions from magnetograms and proxy data can be used, although the long-term behaviour of the reconstructions may not be comparable to the one of TSI. The result of this assessment is important not only for climate studies, but also for reconstructions of TSI back to e.g. the Maunder Minimum time.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFMGC32A..06F
- Keywords:
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- 1650 Solar variability (7537);
- 7537 Solar and stellar variability (1650);
- 7538 Solar irradiance