Reblogged From The Hockeyschtick, with thanks to the KaltSonne blog and a H/T to Michele Casati:
A new paper published in the Journal of Geophysical Research: Space Research shows solar activity peaked at the end of the 20th century, but predicts a strong decrease in solar activity until around 2100 AD to low levels similar to the Dalton Minimum.
|Figure 4 from Steinhilber and Beer shows solar activity peaked at the end of the 20th century, but is predicted to decline to levels similar to the Dalton Minimum during the 21st century. The two different shades of gray correspond to two different models. The Dalton Minimum “D” and Maunder Minimum “M” are notated
Prediction of solar activity for the next 500 years
Friedhelm Steinhilber, Jürg Beer
Abstract: Recently a new low-noise record of solar activity has been reconstructed for the past 9.400 years by combining two 10 Be records from Greenland and Antarctica with 14 C from tree rings [F. Steinhilber et al., 2012]. This record confirms earlier results, namely that the Sun has varied with distinct periodicities in the past. We present a prediction of mean solar magnetic activity averaged over 22 years for the next 500 years mainly based on the spectral information derived from the record of the past solar activity. Assuming that the Sun will continue varying with the same periodicities for the next centuries we extract the spectral information from the past and apply it in two different methods to predict the future of solar magnetic activity. First, the two methods are tested by predicting past changes. Our methods are able to predict periods of high and low solar activity for a few centuries in the past. However, they are less successful in predicting the correct amplitude. Then, the methods were used to predict the period 2000-2500. Both methods predict a period of low activity around 2100 AD. Between 2100 AD and 2350 AD the results are inconsistent regarding the duration of the low activity state in 2100 AD and the level of activity until 2250 AD. Around 2250 AD both methods predict a period of moderate activity. After 2350 AD both methods point to a period of high activity. The period of high activity will end around 2400 AD and will be followed by a period of moderate activity.
Here we follow the approaches by [Abreu et al., 2010; Bonev et al., 2004]
and make use of the spectral information contained in the past solar activity to predict the future 500 years. The
low-noise record [ F. Steinhilber et al., 2012] based on several radionuclide datasets (10Be from Greenland and Antarctica, and 14 C from tree rings) is used as record of solar activity. This record has less noise than the individual records used in previous predictions and therefore can be considered as an improvement of these former studies.
Finally we would like to note that the term “solar activity” is not well defined. While in the past
it was often considered as a synonym for sunspots we use it in this work as a measure of the
general solar magnetic activity which includes both the closed magnetic field associated with
sunspots and the open magnetic field responsible for the modulation of the galactic cosmic rays
and therewith the production rate of cosmogenic radionuclides.
However, as shown by the graph below, the current solar cycle [SC 24, red] is already closely tracking the first solar cycle [SC 5, pink] of the Dalton Minimum, and both are quite weak in comparison to the average of solar cycles 1 through 23 [blue].
The accumulated sunspot anomaly has significantly declined during the current solar cycle: