Correspondences
What is linked, what is not
Each arc joins two phenomena tested on this site. Green and animated: clear link (correlation significant at 5 % after correcting for autocorrelation, or a response outside chance in an event study). Grey: inconclusive test. A statistical link alone does not establish causation.
- Clear link
- Inconclusive
Hypotheses tested
16
Clear links
11
Causation demonstrated
0
Arc width from |r| of the stored result; several tests between the same phenomena are drawn as stacked arcs.
Hypothesis tested: Intense geomagnetic storms are driven by coronal mass ejections and fast streams; their frequency follows the 11-year cycle with a peak in the declining phase (Richardson & Cane, 2012).
Spearman correlation ρ
0.77
95% interval [0.59; 0.87] (block bootstrap)
Pearson correlation r (lag 0 year(s))
0.76
at the strongest lag
Aligned points
63
effective n ≈ 24 (autocorrelation)
p-value
0.00000
two-sided, Fisher z transform, effective n
Period analysed
1963 → 2025
computed on Oct 23, 2026 · engine v1.0
Aligned series (standard deviations, after preprocessing)
Show the data as a table
Correlation by lag (year(s))
Show the data as a table
Superposed epochs
Show the data as a table
Method and sources
Yearly counts of Dst ≤ −100 nT episodes detected in OMNI2 (see Geomagnetic storms) against the SILSO yearly sunspot number. Spearman correlation with a 3-year block bootstrap, Pearson correlation for lags from −4 to +4 years, and superposed epochs of the counts around solar maxima (local maximum of the yearly number over ±5 years, ≥ 60).
Computation parameters
{
"sea": {
"after": 6,
"draws": 2000,
"before": 4,
"maxima_rule": "local maximum of yearly SSN over ±5 years, SSN ≥ 60"
},
"max_lag": 4,
"bootstrap": {
"seed": 20261023,
"block": 3,
"draws": 1000,
"statistic": "spearman"
},
"storm_threshold_nT": -100
}Inputs : silso.ssn.yearly (326 pts, run #49) · omni.dst.hourly (559,191 pts, run #133)
Reading this result
The strong correlation is expected: it reflects the dependence of storms on solar activity, not a forecast; yearly counts are small and the catalogue starts in 1963. Correlation is not causation: common factors (seasons, cycles, trends) or coincidence can produce it. The p-values account for autocorrelation (effective n) but not for preprocessing choices; the confidence interval comes from a block bootstrap. The limits of the source data apply.
SOURCES OF THIS PAGE
- SILSO yearly mean total sunspot number V2.0
-
SILSO World Data Center. The International Sunspot Number, V2.0. Royal Observatory of Belgium, Brussels.
· source page ↗
Licence : CC BY-NC 4.0 · retrieved on Oct 23, 2026 · SHA-256 0ccb2104b03f… - OMNI2 hourly near-Earth solar wind and geomagnetic indices
-
King, J. H., & Papitashvili, N. E. (2005). Solar wind spatial scales in and comparisons of hourly Wind and ACE plasma and magnetic field data. J. Geophys. Res., 110, A02104. OMNI2 data from NASA/GSFC SPDF OMNIWeb; Kp/ap from GFZ Potsdam, Dst from WDC Kyoto, F10.7 from NRC Canada (Penticton).
· doi:10.1029/2004JA010649 · source page ↗
Licence : NASA data, public domain; acknowledge SPDF/OMNIWeb and the index providers · retrieved on Oct 23, 2026 · SHA-256 6de9b217bd4b… - Richardson et al. (2012)
-
Richardson, I. G., & Cane, H. V. (2012). Solar wind drivers of geomagnetic storms during more than four solar cycles. Journal of Space Weather and Space Climate, 2, A01.
· doi:10.1051/swsc/2012001
Licence : Published literature; cited - Gonzalez (1994)
-
Gonzalez, W. D., et al. (1994). What is a geomagnetic storm? Journal of Geophysical Research, 99(A4), 5771–5792.
· doi:10.1029/93JA02867
Licence : Published literature; cited