Predicting solar activity

This astrophysical research led to the reversal of NASAs panel prediction of solar activity.


Variable solar activity, including the eleven-year solar cycle, is believed to be magnetic in origin, with the variable magnetic field generated by a hydromagnetic dynamo operating deep in the solar interior. The precise mechanism for this field generation involves the interaction of magnetohydrodynamic turbulence with rotation for which no fully predictive model currently exists. 

Solar activity has fundamental terrestrial consequences. An increase in solar activity can lead to both an increase in the number and violence of solar flares and coronal mass ejections and significantly change space weather. Therefore a deep understanding of the mechanisms leading to solar magnetic activity is needed. 

Research impact

Recent research into mathematical aspects of dynamo theory and predictability at Leeds has modified the standing of dynamo-based prediction schemes and changed the paradigm for the prediction of long-term solar activity. Professor Steven Tobias, acting as a consultant for the official NASA-funded NOAA-led solar prediction panel for solar cycle 24 reversed the view of the panel from a prediction of high activity to the correct one of a weak cycle 24. 

The impact of this is far-reaching and significant, because the NOAA panel’s prediction is important to a wide range of high-profile end users such as satellite builders and operators, the US Department of Defense and NASA itself. Tobias’ research directly reversed a decision in an area in which a “wrong prediction could be extremely costly”. 

One particular impact of the research’s reversal of the panel prediction is that this “was a factor in NASA’s decision not to fly an extremely costly rendezvous mission … to grab the Hubble Space Telescope”, which “allowed NASA a savings of order of $100million".

Underpinning research

Research by the Astrophysical Fluid Dynamics group at Leeds involves determining mechanisms for the generation and modulation of the solar-activity cycle and quantifies uncertainties of long-term prediction of solar activity. 

This research falls largely into four categories:

  1. Determination of uncertainties in the transport coefficients that are used in models of solar activity
  2. Investigation of the mechanisms for modulation of the basic cycle.
  3. Demonstration of the limits of predictive dynamo models.
  4. Further research in collaboration with a group at ETH Zurich analysing ice-cores, has involved a statistical analysis of proxy data for solar activity.