Observed and Projected Changes in Precipitation Regime over Utah
Notice bibliographique
Résumé
The intermountain west region of the United States, in which the state of Utah resides, relies both economically and socially on the development of a heavy winter mountain snowpack. The retention of water in the snowpack and its timely release is an important part of the hydrological cycle for both the state and the region. Observational evidence of the hydroclimate in Utah shows a reduction in the snowpack along with changing conditions in melting and subsequent runoff - both are occurring earlier in the season. What has not been examined in the region is the proportion of snow-to-rainfall and whether the aforementioned declining trends are evident in the winter precipitation regime, i.e., more rain and less snow. The opening analysis presented here examines this and uses three long term (1915-2003) precipitation and temperature gridded datasets for the state of Utah to determine if the total and snow/rain partition has changed. Results show that the ratio of snow-to-rain has declined over the period. Sensitivity tests were also conducted using a number of temperature threshold methods to differentiate rain versus snow and when applied, all were statistically significant in indicating the decline and as anticipated, the trend is stronger at lower elevations. The declining ratio of snow-to-rain is very likely attributed to global climate change because the pronounced decadal and inter-decadal variations that characterize the central intermountain climate are much less significant in the variation of snow-to-rain ratio. The observations of change in the precipitation regime are consistent with likewise observed changes in temperature that are warming the West. In addition, the analysis indicates a north-south stratification in total precipitation that is placed at the southern boundary of Utah. The logical progression from the aforesaid observational assessment with associated indications is an examination of future projections of snow-to-rain ratios for the state of Utah. Simulations generated by the Canadian Regional Climate Model (CRCM) and the Regional Climate Model version 3 (RCM3), both participants of the North American Regional Climate Change Assessment Program (NARCCAP), were examined from this perspective. The future climate simulations are prescribed by general circulation models and cover the period 2038-2069. Results indicate a similar declining trend in the simulated ratio of snow-to-rain for the state of Utah. The decline in ratio of snow-to-rain is consistent with increases of daily temperature maximums and minimums in both models. However, compared with the simulations forced by the NCEP-DOE Reanalysis (i.e., 1979-2004), the simulated future climate, as driven by general circulation models, exhibits a strong cold bias in the daily temperature minimum with a comparable trend but weaker cold bias in daily temperature maximum. These cold biases enhance the ratio of snow-to-rain in the models, leading the future projection of snow-to-rain ratio to be higher than that in the past decade which is contradictory to the observed trend mentioned previously. The cold bias also forms a cooling, instead of a warming, of the future intermountain climate.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».