The Total Irradiance Monitor (TIM): Instrument Design

Kopp, Greg; Lawrence, G. M.

doi:10.1007/s11207-005-7446-4

Cited by 109 publications

(60 citation statements)

References 10 publications

(6 reference statements)

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“…For example, the A-sensor of the PREMOS TSI radiometer on the PICARD satellite, ''PREMOS-A'', degraded by almost 3,000 ppm in 2 years of operation, during which it was exposed for 300 days (Fehlmann et al 2012;Schmutz et al 2013). This is why all TSI radiometers in space, other than the Hickey-Frieden (HF; Hickey et al 1988) and Earth Radiation Budget Satellite (ERBE; Lee et al 1995) experiments, had a backup channel in order to account for the degradation in the operating instrument (SORCE/TIM has three; Kopp & Lawrence 2005). The backup radiometer is exposed only infrequently and thus degrades only fractionally relative to the primary operational radiometer.…”

Section: Instrument Degradationmentioning

confidence: 99%

Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer (PREMOS/PICARD)

Ball

Schmutz

Fehlmann

et al. 2016

J. Space Weather Space Clim.

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The switching of the total solar irradiance (TSI) backup radiometer (PREMOS-B) to a primary role for 2 weeks at the end of the PICARD mission provides a unique opportunity to test the fundamental hypothesis of radiometer experiments in space, which is that the sensitivity change of instruments due to the space environment is identical for the same instrument type as a function of solar-exposure time of the instruments. We verify this hypothesis for the PREMOS TSI radiometers within the PREMOS experiment on the PICARD mission. We confirm that the sensitivity change of the backup instrument, PREMOS-B, is similar to that of the identically-constructed primary radiometer, PREMOS-A. The extended exposure of the backup instrument at the end of the mission allows for the assessment, with an uncertainty estimate, of the sensitivity change of the primary radiometer from the beginning of the PICARD mission compared to the end, and of the degradation of the backup over the mission. We correct six sets of PREMOS-B observations connecting October 2011 with February 2014, using six ratios from simultaneous PREMOS-A and PREMOS-B exposures during the first days of PREMOS-A operation in 2010. These ratios are then used, without indirect estimates or assumptions, to evaluate the stability of SORCE/TIM and SOHO/VIRGO TSI measurements, which have both operated for more than a decade and now show different trends over the time span of the PICARD mission, namely from 2010 to 2014. We find that by February 2014 relative to October 2011 PREMOS-B supports the SORCE/TIM TSI time evolution, which in May 2014 relative to October 2011 is~0.11 W m À2 , or~84 ppm, higher than SOHO/VIRGO. Such a divergence between SORCE/TIM and SOHO/VIRGO over this period is a significant fraction of the estimated decline of 0.2 W m À2 between the solar minima of 1996 and 2008, and questions the reliability of that estimated trend. Extrapolating the uncertainty indicated by the disagreement of SORCE/TIM and PREMOS with respect to SOHO/VIRGO, we can conclude that it is currently not possible to assess centennial timescale changes in solar irradiance based on any of the presently existing TSI composites. It is imperative to accurately estimate solar irradiance changes from observations in order to extrapolate centennial scale trends important for understanding both long-term solar irradiance changes and the Sun's influence on the Earth's climate.

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Section: Instrument Degradationmentioning

confidence: 99%

Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer (PREMOS/PICARD)

Ball

Schmutz

Fehlmann

et al. 2016

J. Space Weather Space Clim.

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show abstract

“…However, this is not the case as emphasized in Fröhlich (2009a). The author compares the ratio of TSI measured by VIRGO with TSI measured by TIM (Kopp & Lawrence 2005) on-board the NASA Earth Observing System Solar Radiation and Climate Experiment. While VIRGO was launched in 1996, TIM has only been in space since 2003.…”

Section: Introductionmentioning

confidence: 99%

Total solar irradiance since 1996: is there a long-term variation unrelated to solar surface magnetic phenomena?

Steinhilber

2010

A&A

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“…ACRIMSAT/ACRIM3 (Willson and Mordvinov, 2003), SOHO/VIRGO (Fröhlich, 2006) and SORCE/TIM (Kopp and Lawrence, 2005a;Kopp et al, 2005b). Cross-comparison of the three independent TSI records reduces in- VIRGO and TIM sensors is likely responsible for these differences.…”

Section: Total Solar Irradiance Datamentioning

confidence: 99%

Multiscale comparative spectral analysis of satellite total solar irradiance measurements from 2003 to 2013 reveals a planetary modulation of solar activity and its nonlinear dependence on the 11 yr solar cycle

Scafetta

Willson²

2013

Pattern Recogn. Phys.

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The Total Irradiance Monitor (TIM): Instrument Design

Cited by 109 publications

References 10 publications

Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer (PREMOS/PICARD)

Assessing the beginning to end-of-mission sensitivity change of the PREcision MOnitor Sensor total solar irradiance radiometer (PREMOS/PICARD)

Total solar irradiance since 1996: is there a long-term variation unrelated to solar surface magnetic phenomena?

Multiscale comparative spectral analysis of satellite total solar irradiance measurements from 2003 to 2013 reveals a planetary modulation of solar activity and its nonlinear dependence on the 11 yr solar cycle

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