Two empirical models for short‐term forecast of Kp. Issue 3 (14th March 2017)

• Record Type: Journal Article
• Authors: Luo, B.; Liu, S.; Gong, J.
• Is Part Of: Space weather. Volume 15:Issue 3(2017:Mar.)
• Page Start: 503
• Page End: 516
• Publication Date: 2017-03-14
• Subjects: Kp -- forecast -- model -- space weather -- geomagnetic storm; Space environment -- Periodicals; 551.509992
• DOI: 10.1002/2016SW001585
• Languages: English
• ISSNs: 1542-7390

Abstract

Abstract: In this paper, two empirical models are developed for short‐term forecast of the K p index, taking advantage of solar wind‐magnetosphere coupling functions proposed by the research community. Both models are based on the data for years 1995 to 2004. Model 1 mainly uses solar wind parameters as the inputs, while model 2 also utilizes the previous measured K p value. Finally, model 1 predicts K p with a linear correlation coefficient ( r ) of 0.91, a prediction efficiency (PE) of 0.81, and a root‐mean‐square (RMS) error of 0.59. Model 2 gives an r of 0.92, a PE of 0.84, and an RMS error of 0.57. The two models are validated through out‐of‐sample test for years 2005 to 2013, which also yields high forecast accuracy. Unlike in the other models reported in the literature, we are taking the response time of the magnetosphere to external solar wind at the Earth explicitly in the modeling. Statistically, the time delay in the models turns out to be about 30 min. By introducing this term, both the accuracy and lead time of the model forecast are improved. Through verification and validation, the models can be used in operational geomagnetic storm warnings with reliable performance. Key Points: Two empirical Kp models with high prediction accuracy are presented Solar wind‐magnetosphere coupling functions are optimized and utilized to achieve best prediction of Kp Magnetosphere's response time to external solar wind is investigated and incorporated to improve the models