1. Solar Irradiance (Swiss contributions to ILWS) 4th ILWS general meeting, Beijing, June 22-23, 2006 Werner Schmutz, PMOD/WRC, Switzerland (representing Swiss Space Office)

2. Overview Why are solar irradiance measurements required? Future Swiss Irradiance experiments The future of Total Solar Irradiance

3. What is the influence of the Sun on the climate? Graphics: Dr. J. Beer EAWAG, Switzerland ?

4. Solar irradiance variation between maximum and minimum – spectral dependance

5. Rozanov et al. 2001: what UV-wavelength should be observed? Ozone mixing ratio changes (%) due to a 10% increase of the spectral solar flux in 1 wavelength bin (1 nm).

6. Filter Radiometers: LYRA/PROBA2 (launch 2007) PREMOS-PFR/PICARD (launch 2008) LYRA: 7-20, 20-70, 125,215 nm PREMOS: 215, 268, 535, 782 nm

7. C. Fröhlich et al.SOVIM/ISS 2008(?) - 2010 J.-F. Hochedez et al.LYRA/PROBA2 2007 - 2008 W. Schmutz et al. PREMOS/PICARD 2009 - 2019 Future PMOD/WRC Irradiance Measurements (phase C/D)

8. SOVIM on ISS (launch 2008?): Hardware, tests and calibration finished acceptance review passed (almost)

9. LYRA (Status: FM April 2005)

10. LYRA (Status: FM March 2006) BESSY synchrotron calibration at PTB

11. PICARD (PI G. Thuillier) PREMOS – SOVAP – SODISM Total Solar Irradiance Filter Radiometers

12. Summary SWAP (0.1 Hz) + LYRA (60 Hz) on PROBA2 provide the EUV equivalent in Europe of the NOAA SXI + GOES X-ray monitor 2007-2008 SODISM + PREMOS on PICARD will continue in the near UV and visual (+TSI) 2008/2009-2011

13. Total Solar Irradiance measurements present : VIRGO on SoHO (since 1996) ACRIM III on ACRIM-sat (since 2000) TIM on SORCE (since 2003) future: SOVIM (CH/B experiments on ISS 2008) PREMOS-TSI (CH experiment on PICARD 2008) SOVAP (B experiment on PICARD 2008) planned: RAD (CN/CH experiment on KuaFu-A 2012)

14. TSI comparison with observations: cycle 21 – 23 Wenzler et al. 2005, A&A 432, 1057 I TSI =  q I quite sun +  n I network +  f I faculae +  s I sun spot Minimum-I TSI = I quite sun Is this approach supported by observations?

15. Absolutely calibrated TSI measurements TIM/SORCE 2003 -

16. TSI – latest update

17. TSI – comparisons of different composites

18. PMOD composite of the Total Solar Irradiance the aim is to get experimental long-term information about the TSI

19. Total Solar Irradiance observations between 2006 and 2012 ACRIM III 2000 - ? VIRGO/SOHO 1996 - 2007 - ? TIM/SORCE2003 – 2008 - (?) SOVIM/ISS 2008 – 2009 ? PREMOS-TSI/PICARD2008 – 2011 SOVAP/PICARD (SDO 2008-2012 has no TSI instrument) NPOESS2012 National Polar Orbiting Operational Environmental Satellite System may have TSI instrument – but are planned to start not earlier than 2009 (?), more likely as late as 2012

20. Total Solar Irradiance observations between 2006 and 2012 ACRIM III 2000 - ? VIRGO/SOHO 1996 - 2009 (?) TIM/SORCE2003 -2008 - (?) SOVIM/ISS 2008 – 2009 ? PREMOS-TSI/PICARD2008 – 2011 SOVAP/PICARD (SDO 2008-2012 has no TSI instrument) NPOESS2012 National Polar Orbiting Operational Environmental Satellite System may have TSI instrument – but are planned to start not earlier than 2009 (?), more likely as late as 2012 TSI on NPOESS canceled June 2006

21. Total Solar Irradiance observations between 2006 and 2012 ACRIM III 2000 - ? VIRGO/SOHO 1996 - 2007 - 2009 TIM/SORCE2003 – 2008 - (GLORY?) SOVIM/ISS 2008 - 2009 ? PREMOS-TSI/PICARD2008 - 2013 SOVAP/PICARD (SDO 2008-2012 has no TSI instrument) KuaFu-A2012 RAD comprising: SIM = Solar Irradiance Monitor (CN) DOR = Davos Observatory Radiometer (CH)

22. Summary 2 Continuation of long term TSI-measurements requires overlapping missions  There should be always at least two independent operational experiments TSI is most likely observed by two experiments until 2009/2010 The gap 2010-2012 is probably covered by an experiment (extended PICARD and/or GLORY) There is no approved TSI mission after 2009, but:  good chance for RAD on KuaFu-A 2012 Other options for 2nd TSI experiment: DynaMICS ? (proposed by Sylvaine Turck-Chièze, F) PICARD