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: Warm phases of the Atlantic Multidecadal Oscillation go with warmer tropical waters, less shear and a stronger West African monsoon: they should coincide with decades of frequent hurricanes (Goldenberg et al., 2001).
Pearson correlation r (lag 0 year(s))
0.48
95% interval [0.32; 0.62] (block bootstrap)
Aligned points
73
effective n ≈ 54 (autocorrelation)
p-value
0.00021
two-sided, Fisher z transform, effective n
r after a 21-year high-pass filter
0.32
p = 0.006, effective N ≈ 73: year-to-year variations only
Period analysed
1950 → 2022
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
Method and sources
The unsmoothed NOAA PSL AMO (Kaplan SST, North Atlantic 0–70° N, not detrended) is averaged from June to November and compared with the season’s ACE in HURDAT2, from 1950 to 2023 (end of the AMO series). Lag fixed at zero, 5-year block bootstrap. The same calculation is repeated after removing variations slower than 21 years, to test the year-to-year link.
Computation parameters
{
"x": "mean AMO of June–November (NOAA PSL, unsmoothed, Kaplan SST V2)",
"y": "North Atlantic ACE of the season (HURDAT2), 10^4 kt²",
"lag": "fixed at 0",
"bootstrap": {
"seed": 20261023,
"block": 5,
"draws": 1000
},
"from_year": 1950,
"high_pass_years": 21
}Inputs : psl.amo.monthly (2,005 pts, run #40) · hurdat2.ace.yearly (175 pts, run #21)
Reading this result
On the raw series, most of the link comes from the long phases: quiet, cool 1970s–1980s, warm and active 1995–2020. With only two or three AMO cycles in the period, the effective sample is small. The index also carries the long-term warming (not detrended), which inflates the correlation; the high-passed result is more cautious. 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
- Atlantic Multidecadal Oscillation, unsmoothed (NOAA PSL, Kaplan SST)
-
NOAA PSL, AMO index (unsmoothed, from the Kaplan SST V2, North Atlantic 0–70°N), after Enfield et al. (2001).
· doi:10.1029/2000GL012745 · source page ↗
Licence : U.S. Government work, public domain · retrieved on Oct 23, 2026 · SHA-256 9bf4d13f5c69… - HURDAT2 Atlantic hurricane database (NOAA NHC)
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Landsea, C. W., Franklin, J. L. (2013). Atlantic hurricane database uncertainty and presentation of a new database format. Monthly Weather Review 141, 3576–3592 (HURDAT2, NOAA NHC).
· doi:10.1175/MWR-D-12-00254.1 · source page ↗
Licence : U.S. Government work, public domain · retrieved on Oct 23, 2026 · SHA-256 75202780ce56… - Goldenberg et al. (2001)
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Goldenberg, S. B., Landsea, C. W., Mestas-Nuñez, A. M., & Gray, W. M. (2001). The recent increase in Atlantic hurricane activity: causes and implications. Science, 293(5529), 474–479.
· doi:10.1126/science.1060040
Licence : Published literature; cited - Enfield et al. (2001)
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Enfield, D. B., Mestas-Nuñez, A. M., & Trimble, P. J. (2001). The Atlantic multidecadal oscillation and its relation to rainfall and river flows in the continental U.S. Geophysical Research Letters, 28(10), 2077–2080.
· doi:10.1029/2000GL012745
Licence : Published literature; cited