A Kalman Filter Technique for Improving Medium-Term Predictions of the Sunspot Number
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In this work we describe a technique developed to improve medium-term prediction methods of monthly smoothed sunspot numbers. Each month, the predictions are updated using the last available observations (see the monthly output in real time at http://sidc.oma.be/products/kalfil ). The improvement of the predictions is provided by applying an adaptive Kalman filter to the medium-term predictions obtained by any other method, using the six-monthly mean values of sunspot numbers covering the six months between the last available value of the 13-month running mean (the starting point for the predictions) and the “current time” (i.e. now). Our technique provides an effective estimate of the sunspot index at the current time. This estimate becomes the new starting point for the updated prediction that is shifted six months ahead in comparison with the last available 13-month running mean, and it provides an increase of prediction accuracy. Our technique has been tested on three medium-term prediction methods that are currently in real-time operation: The McNish–Lincoln method (NGDC), the standard method (SIDC), and the combined method (SIDC). With our technique, the prediction accuracy for the McNish–Lincoln method is increased by 17 – 30%, for the standard method by 5 – 21% and for the combined method by 6 – 57%.
KeywordsSolar cycle, models Solar cycle, observations Sunspots, statistics
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- Brown, R.G.: 1963, Smoothing Forecasting and Prediction in Discrete Time Series, Prentice Hall, New York, 468. Google Scholar
- Denkmayr, K., Cugnon, P.: 1997, About sunspot number medium-term predictions. In: Heckman, G., Maruboshi, K., Shea, M.A., Smart, D.F., Thompson, R. (eds.) Proceedings of the 5th Solar–Terrestrial Predictions Workshop, Hiraiso Solar Terrestrial Research Center, Japan, 103. Google Scholar
- Koeckelenbergh, A.: 1986, Comments on medium-term prediction of solar activity. In: Simon, P.A., Heckman, G., Shea, M.A. (eds.) Solar–Terrestrial Predictions, US Department of Commerce, NOAA, ERL, Boulder, 113. Google Scholar
- McNish, A.G., Lincoln, J.V.: 1949, Prediction of sunspot numbers. EOS 30, 673. Google Scholar
- Podladchikova, T.: 2006, Identification of unknown noise statistics for non-stationary state space systems. In: Bobtsov, A.A., Nikiforov, V.O. (eds.) Preprints of the 11th International Student Olympiad on Automatic Control (Baltic Olympiad), State University of Information Technologies, Mechanics and Optics, Saint-Petersburg, 103. Google Scholar
- Steward, F.G., Ostrow, S.M.: 1970, Improved version of the McNish–Lincoln method for prediction of solar activity. Telecommun. J. 37, 228. Google Scholar
- Waldmeier, M.: 1968, Sonnenfleckenkurven und die Methode der Sonnenaktivitätsprognose. Astron. Mitt. Eidgenöss. Sternwarte Zürich 286, 13. Google Scholar