Solar activity prediction: Timing predictors and cycle 24

• Published in: Journal of Geophysical Research. A. Space Physics 2002-11, Vol.107 (A11), p.SSH 15-1-SSH 15-7
• Main Author: Schatten, Kenneth
• Format: Article
• Language: English
• Subjects: Astronomy; Diameter, figure, rotation, mass; Earth, ocean, space; Exact sciences and technology; geomagnetic activity; solar activity; solar cycle; solar forecasting; Solar physics; solar radio flux; Solar system; sunspot number
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2002JA009404

Solar activity forecasting uses numerous methods. Some methods employed are purely numerological, whereas others utilize readily available, well‐established mathematical techniques. There often is, however, no physical basis for some of these methods. Within this arena, however, there is a small subset, called “precursors,” which does have a physical basis. We briefly describe the physical basis of these methods and relate them to solar dynamo physics. Further, we develop techniques to reduce one major source of uncertainty or “error” in these solar activity predictions. This uncertainty is in the timing of the solar cycle. The importance of solar activity timing is apparent when one considers that past solar cycles have periods varying from 8 to 17 years. This makes the timing of the solar cycle only second in importance in solar activity prediction to obtaining the amplitude of any cycle. Two solar phenomena are utilized to obtain a “time mark” for each solar cycle. These are the “polar field reversal” and the march of activity centers towards the equator. This latter phenomenon is often referred to as the “butterfly diagram.” These timings essentially provide a “phasing” of the cycle. With this, we provide a preliminary prospective on solar cycle 24.