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Estimating the maximum of the smoothed highest 3-hourly aa index in 3 d by the preceding minimum for the solar cycle
Du, Zhanle1,2
2020-12-15
Source PublicationANNALES GEOPHYSICAE
ISSN0992-7689
Volume38Issue:6Pages:1237-1245
AbstractPredicting the maximum intensity of geomagnetic activity for an upcoming solar cycle is important in space weather service and for planning future space missions. This study analyzed the highest and lowest 3-hourly aa index (aa(H)/aa(L)) in a 3 d interval, smoothed by 363 d to analyze their variation with the 11-year solar cycle. It is found that the maximum of aa(H) (aaHmax) is well correlated with the preceding minimum of either aa(H) (aa(Hmin), r = 0.85) or aa(L) (aa(Lmin), r = 0.89) for the solar cycle. Based on these relationships, the intensity of aa(Hmax) for solar cycle 25 is estimated to be aa(Hmax)(25) = 83.7 +/- 6.9 (nT), about 29 % stronger than that of solar cycle 24. This value is equivalent to the ap index of ap(max)(25) = 47.4 +/- 4.4 (nT) if employing the high correlation between ap and aa (r = 0.93). The maximum of aa(L) (aa(Lmax)) is also well correlated with the preceding aa(Hmin) (r = 0.80). The maximum amplitude of the sunspot cycle (R-m) is much better correlated with high geomagnetic activity (aa(Hmax), r = 0.79) than with low geomagnetic activity (aa(Lmax), r = 0.37). The rise time from aaHmin to aa(Hmax) is weakly anti-correlated to the following aa(Hmax) (r = -0.42). Similar correlations are also found for the 13-month smoothed monthly mean aa index. These results are expected to be useful in understanding the geomagnetic activity intensity of solar cycle 25.
Funding OrganizationNational Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC)
DOI10.5194/angeo-38-1237-2020
WOS KeywordLONG-TERM VARIATIONS ; GEOMAGNETIC-ACTIVITY ; MAGNETIC-FIELD ; SUNSPOT NUMBER ; PRECURSOR ; VARIABILITY ; AMPLITUDE ; CLIMATE ; SHAPE
Language英语
Funding ProjectNational Science Foundation of China (NSFC)[1973058] ; National Science Foundation of China (NSFC)[11603040]
Funding OrganizationNational Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC) ; National Science Foundation of China (NSFC)
WOS Research AreaAstronomy & Astrophysics ; Geology ; Meteorology & Atmospheric Sciences
WOS SubjectAstronomy & Astrophysics ; Geosciences, Multidisciplinary ; Meteorology & Atmospheric Sciences
WOS IDWOS:000600068600001
PublisherCOPERNICUS GESELLSCHAFT MBH
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Document Type期刊论文
Identifierhttp://ir.bao.ac.cn/handle/114a11/80274
Collection中国科学院国家天文台
Corresponding AuthorDu, Zhanle
Affiliation1.Chinese Acad Sci, Natl Astron Observ, Key Lab Solar Act, Beijing 100101, Peoples R China
2.Univ Chinese Acad Sci, Beijing, Peoples R China
Recommended Citation
GB/T 7714
Du, Zhanle. Estimating the maximum of the smoothed highest 3-hourly aa index in 3 d by the preceding minimum for the solar cycle[J]. ANNALES GEOPHYSICAE,2020,38(6):1237-1245.
APA Du, Zhanle.(2020).Estimating the maximum of the smoothed highest 3-hourly aa index in 3 d by the preceding minimum for the solar cycle.ANNALES GEOPHYSICAE,38(6),1237-1245.
MLA Du, Zhanle."Estimating the maximum of the smoothed highest 3-hourly aa index in 3 d by the preceding minimum for the solar cycle".ANNALES GEOPHYSICAE 38.6(2020):1237-1245.
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