Trends, periodicities and ENSO relationships of the annual precipitation over the contiguous United States and Southern Canada
Bibliographic record
Abstract
The century-long (1891-1990) time series of Groisman and Easterling (1994a,b) representing estimates of annual precipitation amounts over five homogeneous regions of the United States and Southern Canada (south of 55° N) were examined for trends, periodicities and ENSO relationships. The trends were not uniformly up or down during the 100-year interval, for any region. From 1891 to about 1930, the trends were downward or negligible. Thereafter, the trends were mostly upward, with cyclic variations superposed. A spectral analysis revealed significant periodicities in the QBO and QTO regions (2-3 years and 3-4 years) as also higher periodicities, some common to all regions and hence seen in the series for the entire region. To study the ENSO relationship, a finer classification of El Nino events was used. Each year was examined to check whether it had an El Nino (EN) and/or a Southern Oscillation Index SOI minimum (SO) and/or warm (W) or cold (C) equatorial eastern Pacific sea surface temperatures SST. Several years were ENSOW, which were further subdivided into two groups viz. Unambiguous ENSOW where El Nino existed and SOI minima and SST maxima were in the middle of the calendar year (May-Aug) and, Ambiguous ENSOW where El Nino existed but the SOI minima and SST maxima were in the early or late part of the calendar year, not in the middle. Other El Nino events were of the type ENSO, ENW, ENC, EN. For the All India summer monsoon rainfall, Unambiguous ENSOW were overwhelmingly associated with droughts. For the rainfall in USA and Canada, relationships were not clear-cut except in the Gulf-Mexico region and some other parts. For these regions, excess rains were associated better with the Unambiguous ENSOW.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.005 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".