39 lines
1.4 KiB
Markdown
39 lines
1.4 KiB
Markdown
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# Detrended CR–Seismic Cross-Correlation Analysis
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Generated: 2026-04-21T10:31:37Z
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Study period: 1976-01-01 – 2019-12-31
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Bin size: 5 days
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Surrogates: 10000 IAAFT
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Lag range: -1000…1000 days
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## Significance table
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| Method | N_eff | r(+15d) | σ_Breth(15d) | Peak r | Peak lag | p_global (IAAFT) | σ_IAAFT |
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|---|---|---|---|---|---|---|---|
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| Raw | 1169 | 0.3099 | 10.85 | 0.4691 | -525 d | 1.0000 | 0.0σ |
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| HP filter | 3027 | 0.0411 | 2.26 | 0.3131 | -525 d | 0.0000 | 3.9σ |
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| STL | 1880 | 0.1098 | 4.77 | 0.1554 | -125 d | 0.0000 | 3.9σ |
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| Sunspot regression | 1850 | 0.1570 | 6.79 | 0.2657 | -525 d | 0.0000 | 3.9σ |
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## Interpretation
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**CAUTION**: The following variants retain p_global < 0.05 after detrending: HP filter, STL, Sunspot regression. Further investigation required.
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## Methods
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### HP filter (Hodrick-Prescott)
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λ = 1.29e+05 calibrated for 5-day bins targeting removal of
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variations longer than ~2000 days (Ravn & Uhlig 2002 scaling of the standard λ=1600).
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### STL decomposition
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Period = 803 bins ≈ 11.0 years
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(11-year solar cycle). seasonal_jump=100, trend_jump=100 for computational efficiency.
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The *residual* component (x − trend − seasonal) is used.
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### Sunspot OLS regression
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Contemporaneous + [0, 30, 90, 180]-day lagged sunspot numbers from SIDC WDC-SILSO.
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The fitted solar-proxy component is subtracted from each series.
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## Figure
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`results/figs/detrended_xcorr.png`
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