Solar Cycles for the next 60 years could become stronger

THE CENTENNIAL GLEISSBERG CYCLE: You’ve heard of the 11-year sunspot cycle. But what about the Centennial Gleissberg Cycle? The Gleissberg Cycle is a slow modulation of the solar cycle, which suppresses sunspot numbers every 80 to 100 years. It may have been responsible for the remarkable weakness of Solar Cycle 24 in 2012-2013. New research published in the journal Space Weather suggests that the minimum of the Gleissberg Cycle has just passed. If so, solar cycles for the next 50 years could become increasingly intense. Read the paper here.

Plain Language Summary

The Earth’s inner radiation belt, dominated by high-energy protons, is influenced by solar activity. Studies have shown a correlation between the 11-year solar cycle and the proton population, with lower solar activity leading to increased proton flux. We analyzed data from NOAA-15 and NOAA-19 satellites to monitor the proton population above the South Atlantic Anomaly. Our findings indicate that the recent increase in solar activity, causing a significant decline in the proton flux, is correlated with the turnover in the Centennial Gleissberg Cycle, a longer-term modulation of solar activity spanning approximately 80–100 years.

As solar activity continues to rise over the next few solar cycles, we anticipate a further decrease in the proton population. This changing space climate will have implications for the design and operation of future satellite missions.