Wolf dispersal in the Rocky Mountains, Western United States: 1993-2008

2017 ◽  
Vol 81 (4) ◽  
pp. 581-592 ◽  
Author(s):  
Michael D. Jimenez ◽  
Edward E. Bangs ◽  
Diane K. Boyd ◽  
Douglas W. Smith ◽  
Scott A. Becker ◽  
...  
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Western United States

Studies on the Distribution and Forecasting of Hail in Western United States *

1951 ◽  
Vol 32 (4) ◽  
pp. 119-131 ◽  
Author(s):  
H. T. Harrison ◽  
W. B. Beckwith
Keyword(s):  
United States ◽  
Great Plains ◽  
Metropolitan Area ◽  
Rocky Mountains ◽  
Rio Grande ◽  
Western United States ◽  
Airborne Radar ◽  
Relative Area ◽  
Satisfactory Method ◽  
Western Great Plains

The highest hail-thunderstorm ratio in the country is found over the western Great Plains and the east slope of the Rocky Mountains in a band extending from the Rio Grande northward to the Canadian border. Point frequency of hail over western United States is of little value in determining relative area exposures to hail. Frequency of hail in a metropolitan area such as Denver is at least ten times as great as random point frequency within that area. Hail probably occurs aloft during the growing stage of each thunderstorm which forms in the Denver Section. Hail is predominantly a post-coldfrontal phenomenon at Denver, but no satisfactory method has been found so far of predicting damaging hail. Airborne radar storm detection equipment offers the greatest hope of avoiding damaging hail in flight.

scholarly journals An Analysis of Precipitation Variability, Persistence, and Observational Data Uncertainty in the Western United States

2008 ◽  
Vol 9 (5) ◽  
pp. 843-865 ◽  
Author(s):  
Kristen J. Guirguis ◽  
Roni Avissar
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Grid Cell ◽  
Western United States ◽  
Data Uncertainty ◽  
Data Similarity ◽  
Observational Uncertainty ◽  
High Bias ◽  
Intermountain Region ◽  
General Climate

Abstract This paper presents an intercomparison of precipitation observations for the western United States. Using nine datasets, the authors provide a comparative climatology and season- and location-specific evaluations of precipitation uncertainty for the western United States and for five subregions that have distinct precipitation climates. All data are shown to represent the general climate features but with high bias among datasets. Interannual variability is similar among datasets with respect to the timing of precipitation excesses and deficits, but important differences occur in the spatial distribution of specific anomalous events. Dataset distribution differences, as represented by their cumulative density functions (CDFs), are statistically significant for 80% of data combinations stratified by subregion and season. The CDFs of anomaly fields are more similar but uncertainty remains, as data differences are significant for 40% of dataset comparisons. Observational uncertainty is low for persistence studies because the data are found to be similar with respect to (i) grid cell estimates of a characteristic persistence time scale and (ii) distributions of anomaly length scales. Spatially, the greatest uncertainty in magnitude differences occurs along the Rocky Mountains in winter, spring, and fall, and along the California coastline in summer. In linear (phase) association, the greatest differences occur in northern Mexico during all seasons; along the Rocky Mountains in winter, spring, and fall; and in California, Nevada, and the intermountain region in summer. Overall, data similarity is lowest in summer as a result of a reduction in phase association and an increase in amplitude differences.

Systematics and paleoecology of Late Cambrian echinoderms from the western United States

1997 ◽  
Vol 71 (6) ◽  
pp. 1091-1109 ◽  
Author(s):  
Colin D. Sumrall ◽  
James Sprinkle ◽  
Thomas E. Guensburg
Keyword(s):  
United States ◽  
Great Basin ◽  
Rocky Mountains ◽  
New Genus ◽  
Western United States ◽  
New Genus And Species ◽  
Late Cambrian ◽  
Lower Ordovician ◽  
Single Piece ◽  
Low Diversity

Although echinoderm debris is locally common, articulated specimens are rare in Late Cambrian rocks from the Great Basin and Rocky Mountains of the western United States and are mostly associated with hardgrounds. The fauna, including cornute stylophorans, trachelocrinid eocrinoids, solute homoiosteleans, and rare edrioasteroids, includes several members of the archaic Cambrian Evolutionary Fauna, which had already passed its maximum diversity for echinoderms. In addition to the low diversity, articulated specimen abundance is very low, averaging only about one-tenth that found in overlying Lower Ordovician units. The transition between the Cambrian and Paleozoic Evolutionary Faunas for echinoderms in North America apparently occurred rapidly very close to the Cambrian-Ordovician boundary, because no unequivocal examples of the Paleozoic fauna (such as crinoids, glyptocystitid rhombiferans, asteroids, or echinoids) were found in the Late Cambrian sections.New taxa include several cothurnocystid stylophorans assigned to Acuticarpus delticus, new genus and species, Acuticarpus? republicensis, new species, and Archaeocothurnus goshutensis, new genus and species; Scotiaecystis? species, a poorly preserved cornute stylophoran with lamellipores; Minervaecystis? species, a fragmentary solute homoiostelean based on several steles; Tatonkacystis codyensis, new genus and species, a well-preserved trachelocrinid eocrinoid with five unbranched arms bearing numerous brachioles; an unnamed, poorly preserved, epispire-bearing eocrinoid; an unnamed, poorly preserved, globular eocrinoid? lacking epispires; and an unnamed, heavily weathered, edrioasterid edrioasteroid. Nearly all holdfasts found in these Upper Cambrian units are single-piece blastozoan types, probably belonging to trachelocrinid and other eocrinoids. Distinctive columnals and thecal plates of several additional undescribed eocrinoids and other echinoderms were locally abundant and are also described.

Wildland fire limits subsequent fire occurrence

2016 ◽  
Vol 25 (2) ◽  
pp. 182 ◽  
Author(s):  
Sean A. Parks ◽  
Carol Miller ◽  
Lisa M. Holsinger ◽  
L. Scott Baggett ◽  
Benjamin J. Bird
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Wildland Fire ◽  
Regulatory Control ◽  
Western United States ◽  
Vegetation Changes ◽  
Fire Occurrence ◽  
Northern Rocky Mountains ◽  
Western Us ◽  
Landscape Level

Several aspects of wildland fire are moderated by site- and landscape-level vegetation changes caused by previous fire, thereby creating a dynamic where one fire exerts a regulatory control on subsequent fire. For example, wildland fire has been shown to regulate the size and severity of subsequent fire. However, wildland fire has the potential to influence other properties of subsequent fire. One of those properties – the extent to which a previous wildland fire inhibits new fires from igniting and spreading within its perimeter – is the focus of our study. In four large wilderness study areas in the western United States (US), we evaluated whether or not wildland fire regulated the ignition and spread (hereafter occurrence) of subsequent fire. Results clearly indicate that wildland fire indeed regulates subsequent occurrence of fires ≥ 20 ha in all study areas. We also evaluated the longevity of the regulating effect and found that wildland fire limits subsequent fire occurrence for nine years in the warm/dry study area in the south-western US and over 20 years in the cooler/wetter study areas in the northern Rocky Mountains. Our findings expand upon our understanding of the regulating capacity of wildland fire and the importance of wildland fire in creating and maintaining resilience to future fire events.

scholarly journals Concentrations of mineral aerosol from desert to plains across the central Rocky Mountains, western United States

2016 ◽  
Vol 23 ◽  
pp. 21-35 ◽  
Author(s):  
Richard L. Reynolds ◽  
Seth M. Munson ◽  
Daniel Fernandez ◽  
Harland L. Goldstein ◽  
Jason C. Neff
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
Western United States ◽  
Central Rocky Mountains

Effect of low Q sediments and crustal Q on Lg attenuation in the United States

1987 ◽  
Vol 77 (4) ◽  
pp. 1197-1210
Author(s):  
Brian J. Mitchell ◽  
H. J. Hwang
Keyword(s):  
United States ◽  
Rocky Mountains ◽  
The United States ◽  
Synthetic Seismograms ◽  
Western United States ◽  
Crustal Velocity ◽  
Crystalline Crust ◽  
Lateral Variations ◽  
Multi Mode ◽  
Q Values

Abstract Q values for Lg and its coda exhibit significant lateral variations across the United States, some of which correlate with known variations in the thickness of shallow sedimentary layers. The possibility that all variations in Lg attenuation are caused by changes in the thickness of shallow sediments is investigated by computing multi-mode synthetic seismograms for crustal models with various thicknesses of low-Q sediments. Using crustal velocity and Q models obtained in previous studies, and reasonable values for the thicknesses and intrinsic Q values of sediments in several regions, we find that the variation of Lg Q values between the Appalachian and Rocky Mountains can easily be produced by varying accumulations of sandstone and shale of Mesozoic age and younger. By contrast, throughout most of the Western United States, neither the low Lg Q values which have been observed nor the regional variation of those values can be explained by accumulations of low-Q sediments. Instead, their explanation appears to require low and laterally varying values of Q in the crystalline crust.

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