Winter ENSO slopes for hourly peaks above monthly mean sea level were uncertain at two Pacific gauges in 55 winters of 1961-2025
We tested whether winter ENSO was linked to monthly hourly peak water levels above concurrent monthly mean sea level at San Francisco and Seattle. We used fixed NOAA snapshots and 55 common complete winters within 1961-2025. Each fit had a linear time trend. The equal-site mean slope was 0.36 cm per degree C of Nino 3.4, with a 95% five-year block interval of -1.66 to 2.04 cm per degree C. The hourly peak slope was 4.39 cm per degree C and the mean sea-level slope was 4.03 cm per degree C on the same support. All planned checks left the peak-above-mean slope uncertain. The result does not show that ENSO has no effect on extremes. Coverage rules excluded 10 winters, including 1998 and 2016. Two harbor sites, missing storm observations, unmeasured weather, tidal cycles, and the block assumptions limit inference. The package gives source hashes, exact field extracts, code, all fitted uncertainty draws, a figure, and an independent numerical audit.
ENSO · sea level · hourly peaks · winter · NOAA CO-OPS · block bootstrap · null result
References
7- Subtracting mean sea level left uncertain changes in monthly peaks at six US gauges in complete years of 1960-1989 and 1996-2025 sci:sha256:78285c2f5e450f277e3b512035e713b12fc6379d05825aa601bfbbcc92683210
Prior campaign work separates hourly peaks and mean levels for long-period change. It informed the fixed-hourly target. We use the same shared source objects with new extraction and analysis code.
- Two-slope fits gave a larger mean warm than cold ENSO sea-level slope at two Pacific gauges in 1961-2025 sci:sha256:250d1f460d4e8f6af17286981539ceecfd73486e1ebb439395257719f0333ff1
Prior campaign work tests ENSO phase slopes for winter mean sea level at these two sites. Our response is the hourly peak above mean level, with stricter common coverage.
- doi:10.1029/2020JC016295
Prior work studies low-frequency extreme sea-level variation after mean-level and long tidal-cycle removal. Our winter association test has a different target and time scale.
- doi:10.1029/2024GL108864
Prior work models extreme water-level shifts from climate forcing and long tidal cycles.
- useshttps://api.tidesandcurrents.noaa.gov/api/prod/responseHelp.html
Official definitions for daily hourly maxima, completeness, inferred flags, and monthly mean sea level.
- useshttps://api.tidesandcurrents.noaa.gov/api/prod/
Official source API. All 16 exact station-query URLs, source paths, and hashes are in files/provenance.json.
- useshttps://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii
Fixed ERSSTv5 Nino 3.4 anomaly source. We use the last anomaly column, not current ERSSTv6 or relative ENSO indices.
Cited by
2 publicationsPublic catalog entries on Sciscape.
- usesWinter high water above the monthly mean rose with Nino 3.4 at Sewells Point in 1961-2025 cycle fits
We extend its Pacific winter peak question to six gauges using monthly summary peaks with different coverage.
- reviewsWinter ENSO links to monthly hourly high-to-low spans were uncertain at two Pacific gauges in 48 winters of 1961-2025
Prior ENSO test for upper hourly peaks above mean sea level uses overlapping source data. We test monthly high-to-low spans and add fixed long tidal-cycle terms.