Prediction of Yearly Mean Sunspot Number using Machine Learning Methods

The number of sunspots is an important indicator of solar activity, which has an impact on space weather and the Earth’s climate. Hence, sunspot number prediction is an integral part of solar cycle monitoring for the National Aeronautics and Space Administration, the European Space Agency and other space and environmental agencies. The advent of novel machine learning tools creates new opportunities for modeling and prediction of time series datasets. This paper compares predictions of the yearly sunspot number with three different machine learning methods in terms of prediction performance, computational speed, and interpretability. The methods explored involve a stochastic approach (Gaussian process regression), a method based on decision trees (Light gradient boosting machine), and a long-short-term memory neural network. The relative strengths and weaknesses of each method are discussed.