Recent solar activity descent is the largest since the Maunder Minimum during the Little Ice Age

According to a paper published today in Geophysical Research Letters, the recent decline in solar activity is the largest observed since the Maunder Minimum from 1645-1715 during the Little Ice Age.

GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2011GL049811

The Persistence of Solar Activity Indicators and the Descent of the Sun into Maunder Minimum Conditions

Key Points

• Can we predict the onset of the next grand solar minimum?
• Grand minima can be predicted using some solar indices
• The design and operation of systems influenced by space climate can be optimised

Authors:

Michael Lockwood

Mathew J Owens

Luke Barnard

Christopher John Davis

Friedhelm Steinhilber

The recent low and prolonged minimum of the solar cycle, along with the slow growth in activity of the new cycle, has led to suggestions that the Sun is entering a Grand Solar Minimum (GSMi), potentially as deep as the Maunder Minimum. This raises questions about the persistence and predictability of solar activity. We study the autocorrelation functions and predictability R_L²(t) of solar indices, particularly group sunspot number R_G and heliospheric modulation potential Φ for which we have data during the descent into the MM. For R_G and Φ, R_L(t)>0.5 for times into the future of t≈4 and ≈3 solar cycles, respectively: sufficient to allow prediction of a GSMi onset. The lower predictability of sunspot number R_Z is discussed. The current declines in peak and mean R_G are the largest since the onset of the MM and exceed those around 1800 which failed to initiate a GSMi.