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Sun-Spots und El Nino

Sun-Spots und El Nino. Ulrich Cubasch Freie Universität Berlin. GPRC Xie & Arkin. NCEP-reanalysis. The precipitation anomaly in the tropical Pacific during solar maximum. van Loon et al, 2006. argument chain (van Loon et al, 2006).

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Sun-Spots und El Nino

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  1. Sun-Spots und El Nino Ulrich Cubasch Freie Universität Berlin

  2. GPRC Xie & Arkin NCEP-reanalysis The precipitation anomaly in the tropical Pacific during solar maximum van Loon et al, 2006

  3. argument chain (van Loon et al, 2006) more solar forcing • stronger convergence zones • more precipitation and stronger trade winds • more upwelling of colder water in the Pacific • La Nina

  4. inverse argument chain(Mendoza, 1991; Handler & Andsager, 1990, Adams et al, 2003) less solar forcing (solar min., vulcanoes) • weaker convergence zones • less precipitation in ITCZ and weaker trade winds • less upwelling of colder water in the Pacific • El Nino

  5. observed The precipitation anomaly during solar maximum van Loon et al, 2006

  6. Wenn ich den Sonnenfleckenzyklus kenne, kann ich ENSO und den Regen in Kalifornien für 10 Jahre vorhersagen!?

  7. …..aberENSO hat keinen 11-Jahreszyklus!

  8. MTM-SVD Eigenmodes in the tropical Pacific White and Tourre, 2003

  9. Response of a delayed oscillator model to solar forcing White et al, 2003

  10. The 11-yr signal in Sun’s irradiance appears to excite a damped resonant response (i.e., the QDO) in the Earth’s climate system. The QDO is excited by a quasi-decadal external signal, not by internal noise or instability in the Earth’s climate system.

  11. Possible Ways for Solar Influence on Climate Sun Sun Visible UV nicht stark genug (Warren et al, 2003) Ozone T, U Strat. Strat. trop. trop. Dynamical impact Radiative impact ? Earth Earth Direct Influence Indirect Influence modified from Kuni Kodera (2005)

  12. Quasi-decadal changes in tropical global-average upper ocean temperature are associated with changes in the overlying troposphere and stratosphere (White, 2005)

  13. Change of meridional temperature gradient Influence on ozone Direct influence on temperature QBO SAO Indirect influence, difficult to measure Change of Hadley & Walker cell Change of Monsoon ? Ocean Thermosphere Mechanism – Influence of the 11-Year Solar Cycle UV radiation Mesosphere Stratopause Stratosphere Circulation changes (wind, waves, meridional BD circulation) Tropopause ? ? Troposphere ? ? QDO, ENSO, QBO modified from Matthes, 2006

  14. Summary • The solar variability generates a ENSO like signal (with La Nina at solar maximum and El Nino at solar minimum). • This ENSO like signal appears to be the QDO in the Pacific, which is phase locked with the solar cycle. • The direct radiative heating anomaly is insufficient to explain the amplitude of the response. • It is therefore likely that the anomalous heating of the stratosphere during solar maximum interacts with the ocean surface. The mechanisms are not yet clear.

  15. The Sun is the key to decadal forecasting….

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