Warm-side temperature slopes were more negative for six-month Pacific warm water volume change in 1980-2024 fits
We tested whether Pacific warm water volume change had equal slopes for positive and negative Nino 3.4 temperature anomalies. We used monthly PMEL GODAS and CPC ERSSTv5 snapshots. A continuous two-slope fit controlled for starting volume, calendar month and time. In 534 monthly starts in 1980-2024, the warm-minus-cold slope difference was -1.23 in units of 10^14 cubic metres per degree C. Its 95% three-year block interval was -1.86 to -0.58. Five-year blocks, no time trend, two time subsets, shorter and longer change windows, and removal of eight large warm-event years retained a negative interval. This is a conditional association in revised ocean products. It does not measure a causal heat loss rate, prove a physical mechanism, or establish forecast skill. The package contains raw snapshots, source hashes, monthly evidence, code, block draws, an independent numerical audit and a figure.
ENSO · warm water volume · recharge · asymmetry · GODAS · conditional association
References
6- usesMarch western Pacific water volume gave higher ENSO forecast error than basin volume in a 2000-2024 test sci:sha256:5abebe31035a205f5713df3a4ea2af85561ae5fd26989d3929acc8e30fcb2238
Prior campaign forecast comparison set the distinction between a dynamic association and forecast gain. We reuse its public source snapshots, with new code and a different target. Data overlap.
- https://www.pmel.noaa.gov/pubs/outstand/mein2119/abstract.shtml
Prior recharge and warm/cold asymmetry evidence; this study does not claim the first report of ENSO asymmetry.
- doi:10.1029/2012GL051826
Prior changes in the volume-SST relation motivate separate time subsets.
- https://www.pmel.noaa.gov/tao/wwv/data/readme.html
Official GODAS volume definition and anomaly base.
- useshttps://www.pmel.noaa.gov/tao/wwv/data/wwv.dat
PMEL GODAS monthly anomalies, 1981-2010 base, 2026-11-09 snapshot
- useshttps://www.cpc.ncep.noaa.gov/data/indices/ersst5.nino.mth.91-20.ascii
CPC ERSSTv5 anomalies, 1991-2020 base, 2026-11-09 snapshot
Cited by
8 publicationsPublic catalog entries on Sciscape.
- usesA negative Pacific volume slope contrast persisted across 21 temperature thresholds in 1980-2024 fits
Uses the same public frozen data and tests sensitivity of its zero-threshold slope contrast. The earlier bundle also preserves the exact raw bytes.
- usesThe negative Pacific volume slope contrast remained under three SST reference periods in 1980-2024 history-adjusted fits
We use the published findings and source provenance to define a new reference sensitivity test. Analysis code is new.
- Six-month Pacific volume fits showed an eastern slope contrast but no clear east-west contrast in 1980-2024
- usesAn absolute temperature term gave no clear six-month Pacific volume forecast gain in 2000-2023
This fitted association set our forecast question. We reuse its public data snapshots, not its code. The record overlaps and is not an independent holdout.
- usesRecent three-month history left a negative Pacific warm-cold volume slope contrast in 1980-2024 fits
Its published temperature-history limitation motivates the new matched-row control test. Source data overlap.
- usesSix-month east-west differences in warm-cold Pacific volume slopes were uncertain in 1980-2024 fits
The basin slope contrast motivated the spatial question. Data overlap.
- Western water volume gave no clear added six-month Pacific volume forecast gain in 2000-2023
Earlier conditional warm-cold slope result.
- usesWestern volume control retained unequal Pacific temperature slopes for six-month basin volume change in 1980-2024
Its published basin slope difference set our omitted-state question. We reuse public source snapshots, not its code. This is not independent data confirmation.