Some Observations of the Mountain Wave in Eastern Colorado

1960 ◽  
Vol 41 (11) ◽  
pp. 627-632
Author(s):  
Norman J. MacDonald ◽  
Henry T. Harrison
Keyword(s):  
Mountain Range ◽  
Mountain Wave ◽  
Mountain Waves ◽  
Period Analysis ◽  
Middle Troposphere ◽  
The North ◽  
Northwesterly Wind

Observations of the mountain wave that forms just to the east of the north-south mountain range in eastern Colorado were collected over a four-year period. Analysis of the circulation in the middle troposphere shows that mountain waves in general and strong waves in particular are more likely to form with a northwesterly wind than with wind from any other direction.

Meteorological Problems in Forecasting Mountain Waves*

1954 ◽  
Vol 35 (8) ◽  
pp. 363-371 ◽  
Author(s):  
DeVer Colson
Keyword(s):  
Static Stability ◽  
Mountain Range ◽  
Mountain Wave ◽  
Mountain Waves ◽  
Wave Development ◽  
Strong Winds ◽  
Wind Shears ◽  
Upper Level ◽  
Meteorological Problems ◽  
Meteorological Phenomenon

The standing-wave development to the lee of prominent mountain ridges presents not only an interesting meteorological phenomenon but also a definite hazard to certain aircraft operations. An analysis of the mountain-wave observations in the Sierras indicates the presence of strong winds normal to the mountain range as well as large vertical wind shears; and an inversion or at least a stable layer near the level of the mountain crest. Changes in the pressure and temperature patterns at both the surface and 500-mb level are shown for two examples of more intense wave developments. Also, mean surface and upper-level pressure and temperature patterns are shown for the strong-wave days. The association between these mean patterns and surface frontal movements, upper-level troughs, strong temperature gradients, and the jet stream are discussed. An example of the effect of wind shear and static stability is shown using equations and methods developed by Scorer. Data on the occurrence of mountain-wave activity in other mountainous areas of the West are now being collected. Two examples of these results are shown.

scholarly journals Decoupling between Precipitation Processes and Mountain Wave Induced Circulations Observed with a Vertically Pointing K-Band Doppler Radar

2019 ◽  
Vol 11 (9) ◽  
pp. 1034 ◽  
Author(s):  
Sergi Gonzalez ◽  
Joan Bech ◽  
Mireia Udina ◽  
Bernat Codina ◽  
Alexandre Paci ◽  
...  
Keyword(s):  
Doppler Radar ◽  
Microwave Radiometer ◽  
Mountain Range ◽  
Mountain Wave ◽  
Vertical Column ◽  
Mountain Waves ◽  
Low Level ◽  
Eastern Pyrenees ◽  
Microphysical Processes ◽  
Wave Induced

Recent studies reported that precipitation and mountain waves induced low tropospheric level circulations may be decoupled or masked by greater spatial scale variability despite generally there is a connection between microphysical processes of precipitation and mountain driven air flows. In this paper we analyse two periods of a winter storm in the Eastern Pyrenees mountain range (NE Spain) with different mountain wave induced circulations and low-level turbulence as revealed by Micro Rain Radar (MRR), microwave radiometer and Parsivel disdrometer data during the Cerdanya-2017 field campaign. We find that during the event studied mountain wave wind circulations and low-level turbulence do not affect neither the snow crystal riming or aggregation along the vertical column nor the surface particle size distribution of the snow. This study illustrates that precipitation profiles and mountain induced circulations may be decoupled which can be very relevant for either ground-based or spaceborne remote sensing of precipitation.

Trends and Variability of North American Cool-Season Extratropical Cyclones: 1979–2019

2021 ◽  
Author(s):  
Robert Fritzen ◽  
Victoria Lang ◽  
Vittorio A. Gensini
Keyword(s):  
North American ◽  
Research Question ◽  
Weather Conditions ◽  
Extratropical Cyclones ◽  
Mountain Range ◽  
Cool Season ◽  
The North ◽  
Primary Driver ◽  
Regional Reanalysis ◽  
Log Linear

AbstractExtratropical cyclones are the primary driver of sensible weather conditions across the mid-latitudes of North America, often generating various types of precipitation, gusty non-convective winds, and severe convective storms throughout portions of the annual cycle. Given ongoing modifications of the zonal atmospheric thermal gradient due to anthropogenic forcing, analyzing the historical characteristics of these systems presents an important research question. Using the North American Regional Reanalysis, boreal cool-season (October–April) extratropical cyclones for the period 1979–2019 were identified, tracked, and classified based on their genesis location. Additionally, bomb cyclones—extratropical cyclones that recorded a latitude normalized pressure fall of 24 hPa in 24-hr—were identified and stratified for additional analysis. Cyclone lifespan across the domain exhibits a log-linear relationship, with 99% of all cyclones tracked lasting less than 8 days. On average, ≈ 270 cyclones were tracked across the analysis domain per year, with an average of ≈ 18 year−1 being classified as bomb cyclones. The average number of cyclones in the analysis domain has decreased in the last 20 years from 290 year−1 during the period 1979–1999 to 250 year−1 during the period 2000–2019. Spatially, decreasing trends in the frequency of cyclone track counts were noted across a majority of the analysis domain, with the most significant decreases found in Canada’s Northwest Territories, Colorado, and east of the Graah mountain range. No significant interannual or spatial trends were noted with bomb cyclone frequency.

scholarly journals Nondissipative and Dissipative Momentum Deposition by Mountain Wave Events in Sheared Environments

2018 ◽  
Vol 75 (8) ◽  
pp. 2721-2740 ◽  
Author(s):  
Christopher G. Kruse ◽  
Ronald B. Smith
Keyword(s):  
Broad Spectrum ◽  
Numerical Models ◽  
Wrf Model ◽  
Vertical Wind Shear ◽  
Mountain Wave ◽  
Subsequent Evolution ◽  
Event Duration ◽  
Mountain Waves ◽  
Vertical Dispersion ◽  
Nonlinear Transient

AbstractMountain waves (MWs) are generated during episodic cross-barrier flow over broad-spectrum terrain. However, most MW drag parameterizations neglect transient, broad-spectrum dynamics. Here, the influences of these dynamics on both nondissipative and dissipative momentum deposition by MW events are quantified in a 2D, horizontally periodic idealized framework. The influences of the MW spectrum, vertical wind shear, and forcing duration are investigated. MW events are studied using three numerical models—the nonlinear, transient WRF Model; a linear, quasi-transient Fourier-ray model; and an optimally tuned Lindzen-type saturation parameterization—allowing quantification of total, nondissipative, and dissipative MW-induced decelerations, respectively. Additionally, a pseudomomentum diagnostic is used to estimate nondissipative decelerations within the WRF solutions. For broad-spectrum MWs, vertical dispersion controls spectrum evolution aloft. Short MWs propagate upward quickly and break first at the highest altitudes. Subsequently, the arrival of additional longer MWs allows breaking at lower altitudes because of their greater contribution to u variance. As a result, minimum breaking levels descend with time and event duration. In zero- and positive-shear environments, this descent is not smooth but proceeds downward in steps as a result of vertically recurring steepening levels. Nondissipative decelerations are nonnegligible and influence an MW’s approach to breaking, but breaking and dissipative decelerations quickly develop and dominate the subsequent evolution. Comparison of the three model solutions suggests that the conventional instant propagation and monochromatic parameterization assumptions lead to too much MW drag at too low an altitude.

The Invasion of Plague in Early Modern Italy

2019 ◽  
pp. 23-50
Author(s):  
John Henderson
Keyword(s):  
Early Modern ◽  
Preventive Measures ◽  
Northern Italy ◽  
Reggio Emilia ◽  
Health Board ◽  
Mountain Range ◽  
Physical Barrier ◽  
The North ◽  
Early Modern Italy ◽  
The Dead

This chapter discusses the origins and spread of plague in northern Italy. Plague arrived in Italy in 1629 with French and German troops. It is no accident that the initial cases of plague identified in October of 1629 were first in Piedmont in the Val di Susa, west of Turin and near the border with France, and secondly in the Valtellina in Lombardy, subsequently travelling to Lake Como to the north of Milan. Other cities in northern Italy soon became infected and on May 6, 1630, the authorities as far south as Bologna announced the official outbreak of plague. Judging by the rapidity with which plague spread between these northern urban centres, one would have expected the epidemic to have arrived in Tuscany by early May, given that Bologna is only 65 miles north of Florence, but it was delayed by both natural and man-made factors. Tuscany is separated from Reggio-Emilia by the Apennine mountain range, which provided a physical barrier and facilitated the control of traffic coming from the north. The chapter then traces the preventive measures adopted by the health board as the plague approached Tuscany, including cordons sanitaires along frontiers, the removal of the sick to quarantine centres, and the rapid burial of the dead.

scholarly journals Passive imaging of collisional orogens: a review of a decade of geophysical studies in the Pyrénées

2022 ◽  
Vol 193 ◽  
pp. 1
Author(s):  
Sébastien Chevrot ◽  
Matthieu Sylvander ◽  
Antonio Villaseñor ◽  
Jordi Díaz ◽  
Laurent Stehly ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Mountain Range ◽  
Seismic Signals ◽  
Passive Imaging ◽  
Tomographic Images ◽  
Bouguer Anomalies ◽  
The North ◽  
Eastern Pyrenees ◽  
Collisional Orogens ◽  
Central Pyrenees

This contribution reviews the challenges of imaging collisional orogens, focusing on the example of the Pyrenean domain. Indeed, important progresses have been accomplished regarding our understanding of the architecture of this mountain range over the last decades, thanks to the development of innovative passive imaging techniques, relying on a more thorough exploitation of the information in seismic signals, as well as new seismic acquisitions. New tomographic images provide evidence for continental subduction of Iberian crust beneath the western and central Pyrénées, but not beneath the eastern Pyrénées. Relics of a Cretaceous hyper-extended and segmented rift are found within the North Pyrenean Zone, where the imaged crust is thinner (10–25 km). This zone of thinned crust coincides with a band of positive Bouguer anomalies that is absent in the Eastern Pyrénées. Overall, the new tomographic images provide further support to the idea that the Pyrénées result from the inversion of hyperextended segmented rift systems.

scholarly journals Observation of Shaheen Falcon Falco peregrinus peregrinator (Aves: Falconiformes: Falconidae) in the Nilgiris, Tamil Nadu, India

2017 ◽  
Vol 9 (10) ◽  
pp. 10850
Author(s):  
Arockianathan Samson ◽  
Balasundaram Ramakrishnan ◽  
Palanisamy Santhoshkumar ◽  
Sivaraj Karthick
Keyword(s):  
Tamil Nadu ◽  
Mountain Range ◽  
Falco Peregrinus ◽  
The North ◽  
The Nilgiris

A total of 45 sightings of 57 individual Shaheen Falcons were recorded from 2014–2016 from different locations in the Nilgiris mountain range, and eight nests were located on separate rocky cliffs.  Most of the nests (n= 6) were situated at elevations ranging from 1500–2500 m and 45% of the nests were located on the north facing exposures.

scholarly journals Effect of Extreme Weather Events on the Sedimentation of the Bay of Samaná, Dominican Republic (1900–2016)

2019 ◽  
Vol 11 (3) ◽  
pp. 56 ◽  
Author(s):  
Ramón A. Delanoy ◽  
Misael Díaz-Asencio ◽  
Rafael Méndez-Tejeda
Keyword(s):  
Accumulation Rate ◽  
Marine Species ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Rainfall Regime ◽  
Mountainous Area ◽  
Mountain Range ◽  
The South ◽  
The North ◽  
Weather Events

The Bay of Samaná, formed by tectonism and sedimentation, is delimited to the north by the peninsula of the same name, to the south by the north slope of the Eastern Mountain Range and Los Haitises National Park, to the east by the Atlantic Ocean, and to the west by the ancient Gran Estero, today the Lower Yuna. There follows a process of continuous degradation by the existing tectonic forces and the sediment contributions by the Yuna, Yabón, and La Yeguada rivers to the south as well as by the landslides of the mountainous area of the Samaná Peninsula, during periods of storms and hurricanes. The coastal area of Samaná Bay has altered by 2.17 km2 at the mouth of the Yuna River from 2003–2015. The high turbidity level has affected coral reefs and marine species.  The  mangroves  are  lost  faster  than  they  are  regenerated  by  the  coastline’s change. Variations in the elemental compositions of calcium and iron show the terrigenous influence on the dynamics of the bay during Extreme Weather Events (EWP) in the river basins that flow into it. Abrupt changes in the rainfall regime produced an equal change in the estuary sedimentation regime, according to the 210Pb. In the 2007–2016 period, a column of sediment that reached 38 cm and a 12 cm to 8.4 km column were deposited 4 km southeast of the municipality of Sánchez and east of the mouth of the Yuna River. The Sedimentary Accumulation Rate is very high, and the content of heavy metals exceeds the threshold values of Table SQuirt.

scholarly journals Von Expeditionsberichten zum Führer — die Anfänge der Ratgeber für Riesengebirgereisende an der Jahrhundertwende des 18. zum 19. Jahrhundert

2019 ◽  
Vol 12 ◽  
pp. 33-53
Author(s):  
Jan Pacholski
Keyword(s):  
Point Of View ◽  
Mountain Range ◽  
Special Role ◽  
The North ◽  
Counter Reformation ◽  
Border Dispute ◽  
History Of ◽  
Nature Studies ◽  
The One ◽  
Travel Accounts

From travel accounts to guidebooks: The beginnings of guidebooks to the Giant Mountains Karkonosze for travellers in the late 18th and early 19th centuryIn the history of European tourism the Giant Mountains Karkonosze occupy a unique place thanks to the Chapel of St. Lawrence, funded by Count Christoph Leopold Schaffgotsch and located on the summit of Śnieżka. Its construction in the Habsburg dominions in the turbulent period of the Counter-Reformation was meant to finally put an end to the Silesian-Bohemian border dispute and become a visible sign of Catholic rule over the highest mountain range of the two neighbouring countries. The construction of the chapel also marked the beginning of tourism in the highest range of the Sudetes; initially, its nature was religious and focused on pilgrimages to the summit of Śnieżka, featuring, in addition to local inhabitants, also sanatorium visitors to Cieplice Warmbrunn, which was owned by the Schaffgotschs.After the three Silesian Wars, as a result of which the lands to the north of the mountains were separated from the Habsburgs’ Kingdom of Bohemia, the situation in the region changed radically. The Counter-Reformation pressure ceased and the Lutherans began to grow in importance, supported as they were by the decidedly pro-Protestant Prussian state, governed by its tolerant monarch.The period was also marked by an unprecedented growth in the literature on the Giant Mountains — there were poems Tralles, nature studies Volkmar and travel accounts GutsMuths, Troschel and others written about the highest range of the Sudetes. A special role among these writings was played by works aimed at introducing the public from the capital Berlin to the new province of the Kingdom of Prussia, especially to the mountains, so exotic from the point of view of the “groves and sands” of Brandenburg. These publications were written primarily by Lutheran clergymen, which was not without significance to the nature of the works. This was also a time when the first guidebooks to the Giant Mountains were written, with many of their authors also coming from the same milieu.What emerges from this image is a kind of confessionalisation of tourism in the highest mountains of Silesia and Bohemia: on the one hand there are mass Catholic pilgrimages and on the other — a new type of individual tourists who, with a book in hand, traverse mountain paths in a decidedly more independent fashion.

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