Comparison of the PMOD, ACRIM and IRMB Composite Total Solar irradiance time series
Abstract
Since November 1978 a set of total solar irradiance (TSI) measurements from space is available, yielding a time series of more than 25 years. From measurements made by different space radiometers (HF on NIMBUS~7, ACRIM I on SMM, ACRIM II on UARS, VIRGO on SOHO, ACRIM III on ACRIMSat and TIM on SORCE) a composite record of TSI can be constructed. Presently, there are three composites available, called PMOD, ACRIM and IRMB, which all are based on the same original data before the advent of VIRGO on SOHO. Afterwards, the ACRIM composite is using ACRIM-II and III and the PMOD and IRMB VIRGO data. The differences arise from the different ways to correct for sensitivity changes. A further difference is that the PMOD composite also corrects the early HF data for degradation and thus can provide reliable data for TSI around the maximum of solar cycle 21 before the advent of ACRIM-I. The origin of the differences will be discussed in detail and illustrated by comparison with ERBE data and a independent TSI reconstruction from Kitt-Peak magnetograms.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFMSH33C..02F
- Keywords:
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- 7537 Solar and stellar variability (1650);
- 7538 Solar irradiance