scholarly journals The erosion of glaciated mountains: evidence from hypsoclinometry

2019 ◽  
Vol 21 (1) ◽  
pp. 5-14
Author(s):  
Ian S. EVANS
Keyword(s):  
Standard Deviation ◽  
Small Proportion ◽  
Steep Slope ◽  
Mountain Range ◽  
Slope Gradient ◽  
Frequency Distributions ◽  
Mountain Ranges ◽  
Steep Slopes ◽  
Mountain Glaciation ◽  
Different Altitudes

Mountain glaciation involves the erosion of cirques and troughs, which increase steep slopes but also produce gentle slopes in cirque floors and trough floors. This is expected to increase the variability of slope gradients at related altitudes. Taking a whole mountain range, its distributions of altitude and slope can be analysed to establish a signal of glacial modification. Frequency distributions of altitude (hypsometry) and gradient (clinometry) alone do not seem adequate. Taking these two variables together – hypsoclinometry, plotting slope gradient against altitude – is more promising. Frequency distributions of slope gradient at different altitudes are exemplified here for mountain ranges in British Columbia and Romania, together with altitudinal variations of steep or gentle slopes. Cirque headwalls give the clearest morphometric signature of glaciation. Steep (especially the steepest) slopes are concentrated at cirque altitudes, increasing mean, median, standard deviation (SD) and inter-quartile range (IQR) of gradients, especially above cirque floors. There is only a small increase in SD and IQR at cirque floor altitudes. Hypsometric maxima and increased proportions of gentle slopes at cirque floor altitudes are clear only in mountain ranges densely occupied by cirques. This relates to the small proportion of each cirque (about 28%) occupied by the floor. Concentrations of steep slope aspects in directions favoured by local glaciers provide further evidence of glacial modification. The most general morphometric effect of glaciation, however, is the increase in steep slopes at cirque headwall altitudes. Thus it is possible to rank mountain ranges by degree of glacial modification.

The Design and Construction of the Chinipas Slope Pipeline Crossing

2016 ◽  
Author(s):  
Agostino Napolitano ◽  
Guido Guidotti ◽  
Andrea Marsili ◽  
Alessandro Fabbri ◽  
Marco Menichetti ◽  
...  
Keyword(s):  
Environmental Science ◽  
Three Dimensional ◽  
Steep Slope ◽  
The State ◽  
Mountain Range ◽  
Natural Gas Pipeline ◽  
Dimensional Reconstruction ◽  
Pipeline Project ◽  
The University ◽  
Steep Slopes

SAIPEM has been awarded the engineering, procurement and construction of “El Encino - Topolobampo” Natural Gas Pipeline Project in Mexico. The 30” pipeline begins in El Encino, in the state of Chihuahua, and terminates in Topolobampo, in the state of Sinaloa. It runs in a West-South West direction perpendicularly crossing the “Sierra Madre Occidental”, a mountain range characterized by uneven morphology with deep and narrow valleys and steep slopes. Near the village of Santa Matilde, before reaching the Chinipas River, the pipeline route has to overcome a 150 meters high steep slope on the left side of the valley of Chinipas. This slope features a sub vertical rocky cliff with a 55 meters drop in the upper section. A trenchless crossing of the slope was designed and executed to safely cross the steep slope by means of raise borer and tunnel. Since the area was nearly inaccessible, SAIPEM, for the first time in the design of a trenchless crossing of slopes, has performed the geomechanical study using a remote sensing process based on the Structure from Motion (SfM) technique for a three-dimensional reconstruction of the outcrop of the cliff. The activity has been carried out in collaboration with the Department of Earth, Life and Environmental Science of the University of Urbino. The results of the study led to the optimization of the trenchless geometry maintaining the raise bore into the competent rock avoiding frequent lithological variations critical during the drilling and identifying a suitable tunnel entrance location.

scholarly journals Effects of glaciation on the clinometry and hypsometry of the Romanian Carpathians

2018 ◽  
Author(s):  
Niculita Mihai ◽  
Ian S Evans
Keyword(s):  
Standard Deviation ◽  
Digital Elevation Model ◽  
Slope Gradient ◽  
General Increase ◽  
Mountain Ranges ◽  
Digital Elevation ◽  
The Alps ◽  
Romanian Carpathians ◽  
Elevation Model

SRTM1 Digital Elevation Model for many mountain ranges in Romania were processed to provide slope gradient distributions for each 50 m band of altitude. The effects of cirques are seen in an increase in standard deviation of gradient, and a spread in all percentiles, especially an increase in the 95th, at relevant altitudes. Otherwise, variations in median gradient with altitude differ between ranges, and do not show the general increase found in the Alps below cirque floor altitudes by several authors.

scholarly journals Effects of glaciation on the clinometry and hypsometry of the Romanian Carpathians

2018 ◽  
Author(s):  
Niculita Mihai ◽  
Ian S Evans
Keyword(s):  
Standard Deviation ◽  
Digital Elevation Model ◽  
Slope Gradient ◽  
General Increase ◽  
Mountain Ranges ◽  
Digital Elevation ◽  
The Alps ◽  
Romanian Carpathians ◽  
Elevation Model

SRTM1 Digital Elevation Model for many mountain ranges in Romania were processed to provide slope gradient distributions for each 50 m band of altitude. The effects of cirques are seen in an increase in standard deviation of gradient, and a spread in all percentiles, especially an increase in the 95th, at relevant altitudes. Otherwise, variations in median gradient with altitude differ between ranges, and do not show the general increase found in the Alps below cirque floor altitudes by several authors.

The composition of milk. Part II: Variation in the percentage of mineral constituents in cow’s milk, and their relationship with the solids not fat and protein content

1927 ◽  
Vol 17 (1) ◽  
pp. 72-93 ◽  
Author(s):  
H. T. Cranfield ◽  
D. G. Griffiths ◽  
E. R. Ling
Keyword(s):  
Standard Deviation ◽  
Phosphoric Acid ◽  
Protein Content ◽  
Ash Content ◽  
Probable Error ◽  
Cow’S Milk ◽  
Frequency Distributions ◽  
Cow's Milk ◽  
Mineral Constituents

1. 670 samples of the mixed milk from 15 herds were analysed, and the average percentages of total ash, soluble ash, insoluble ash, lime and phosphoric acid are given.2. Tables showing frequency distributions are also given, with the standard deviation, mean and probable error of mean for each constituent determined.3. Various correlations of these constituents with solids not fat and protein have been prepared, and these correlations are illustrated by graphs.It is observed that the total ash falls with the solids not fat until low values of solids not fat are reached, when the ash content appears to rise. This variation is confirmed by a curve illustrating the variation in ash content of samples of individual cow’s milk. Soluble ash rises as the solids not fat falls, but the insoluble ash shows a reverse variation. Lime and phosphoric acid both fall with the solids not fat.

scholarly journals 1414. #Vaccine Twitter Influencers: is it Just About Reach and Followers?

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S714-S715
Author(s):  
Jean-Etienne Poirrier ◽  
Theodore Caputi ◽  
John Ayers ◽  
Mark Dredze ◽  
Sara Poston ◽  
...  
Keyword(s):  
United States ◽  
Social Media ◽  
Standard Deviation ◽  
Small Proportion ◽  
The United States ◽  
Research Support ◽  
Policy Makers ◽  
Media Messages ◽  
Social Media Platforms ◽  
The Impact

Abstract Background A small number of powerful users (“influencers”) dominates conversations on social media platforms: less than 1% of Twitter accounts have at least 3,000 followers and even fewer have hundreds of thousands or millions of followers. Beyond simple metrics (number of tweets, retweets...) little is known about these “influencers”, particularly in relation to their role in shaping online narratives about vaccines. Our goal was to describe influential Twitter accounts that are driving conversations about vaccines and present new metrics of influence. Methods Using publicly-available data from Twitter, we selected posts from 1-Jan-2016 to 31-Dec-2018 and extracted the top 5% of accounts tweeting about vaccines with the most followers. Using automated classifiers, we determined the location of these accounts, and grouped them into those that primarily tweet pro- versus anti-vaccine content. We further characterized the demographics of these influencer accounts. Results From 25,381 vaccine-related tweets available in our sample representing 10,607 users, 530 accounts represented the top 5% by number of followers. These accounts had on average 1,608,637 followers (standard deviation=5,063,421) and 340,390 median followers. Among the accounts for which sentiment was successfully estimated by the classifier, 10.4% (n=55) posted anti-vaccine content and 33.6% (n=178) posted pro-vaccine content. Of the 55 anti-vaccine accounts, 50% (n=18) of the accounts for which location was successfully determined were from the United States. Of the 178 pro-vaccine accounts, 42.5% (n=54) were from the United States. Conclusion This study showed that only a small proportion of Twitter accounts (A) post about vaccines and (B) have a high follower count and post anti-vaccine content. Further analysis of these users may help researchers and policy makers better understand how to amplify the impact of pro-vaccine social media messages. Disclosures Jean-Etienne Poirrier, PhD, MBA, The GSK group of companies (Employee, Shareholder) Theodore Caputi, PhD, Good Analytics Inc. (Consultant) John Ayers, PhD, GSK (Grant/Research Support) Mark Dredze, PhD, Bloomberg LP (Consultant)Good Analytics (Consultant) Sara Poston, PharmD, The GlaxoSmithKline group of companies (Employee, Shareholder) Cosmina Hogea, PhD, GlaxoSmithKline (Employee, Shareholder)

scholarly journals [Re]covering Jeddah’s Wadis – Building the City’s Resilience through Green Infrastructure

2018 ◽  
Vol 11 (4) ◽  
pp. 228
Author(s):  
Hanaa Motasim
Keyword(s):  
Green Infrastructure ◽  
Rain Water ◽  
Mountain Range ◽  
Water Drainage ◽  
Severe Damage ◽  
Mountain Ranges ◽  
Natural Flow ◽  
The Rich ◽  
The City ◽  
Green Corridors

Jeddah, Saudi Arabia’s largest coastal city, is positioned between two prominent natural features: the mountain range on its eastern side and the Red Sea on its west. The city faces many challenges central to which is storm water drainage. The natural drainage of the city through its pre-existing wadis, bringing down the rain water from the steep mountain ranges through the low inclining coastal plane and into the sea, has been interrupted in the last few decades by massive road infrastructural projects cutting through the city and interrupting the natural flow. The outcome of these interventions has been excessive flooding calamities, of which the ones in 2009 and 2011 were the most extreme, causing severe damage to infrastructure, property and lives.In light of climate change the intensity of flash floods is expected to increase, placing enormous stress on the city. To control the floods the city has pushed forward heavily engineered solutions, canalizing the rich network of wadis, almost 80 in number, into 4 major concrete channels that discharge the rain water accumulated in the mountains directly into the sea. This solution, which has been prohibitive in cost, has robbed the city of any potential of utilizing the precious supply of rain water. This paper explores the potential of recovering Jeddah’s wadis and creating green corridors across the city. As opposed to engineered solutions which address singular problematics, green infrastructures could provide numerous benefits to the city and the region as a whole.

scholarly journals Impact of North Atlantic Oscillation on the Snowpack in Iberian Peninsula Mountains

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 105 ◽  
Author(s):  
Esteban Alonso-González ◽  
Juan I. López-Moreno ◽  
Francisco M. Navarro-Serrano ◽  
Jesús Revuelto
Keyword(s):  
North Atlantic Oscillation ◽  
Iberian Peninsula ◽  
Sierra Nevada ◽  
North Atlantic ◽  
Snow Water Equivalent ◽  
Mountain Range ◽  
Winter Climate ◽  
Mountain Ranges ◽  
Iberian Range ◽  
The Impact

The North Atlantic Oscillation (NAO) is considered to be the main atmospheric factor explaining the winter climate and snow evolution over much of the Northern Hemisphere. However, the absence of long-term snow data in mountain regions has prevented full assessment of the impact of the NAO at the regional scales, where data are limited. In this study, we assessed the relationship between the NAO of the winter months (DJFM-NAO) and the snowpack of the Iberian Peninsula. We simulated temperature, precipitation, and snow data for the period 1979–2014 by dynamic downscaling of ERA-Interim reanalysis data, and correlated this with the DJFM-NAO for the five main mountain ranges of the Iberian Peninsula (Cantabrian Range, Central Range, Iberian Range, the Pyrenees, and the Sierra Nevada). The results confirmed that negative DJFM-NAO values generally occur during wet and mild conditions over most of the Iberian Peninsula. Due to the direction of the wet air masses, the NAO has a large influence on snow duration and the annual peak snow water equivalent (peak SWE) in most of the mountain ranges in the study, mostly on the slopes south of the main axis of the ranges. In contrast, the impact of NAO variability is limited on north-facing slopes. Negative (positive) DJFM-NAO values were associated with longer (shorter) duration and higher (lower) peak SWEs in all mountains analyzed in the study. We found marked variability in correlations of the DJFM-NAO with snow indices within each mountain range, even when only the south-facing slopes were considered. The correlations were stronger for higher elevations in the mountain ranges, but geographical longitude also explained the intra-range variability in the majority of the studied mountains.

scholarly journals Hidden Hazards: the conditions that potentially enabled the mudflow disaster at Villa Santa Lucía in Chilean Patagonia

2020 ◽  
Author(s):  
Marcelo A. Somos-Valenzuela ◽  
Joaquín E. Oyarzún-Ulloa ◽  
Ivo J. Fustos-Toribio ◽  
Natalia Garrido-Urzua ◽  
Chen Ningsheng
Keyword(s):  
Water Content ◽  
Heat Waves ◽  
Hazard Mapping ◽  
Mountain Range ◽  
Mass Wasting ◽  
Mountain Areas ◽  
Complex Process ◽  
Chilean Patagonia ◽  
Geotechnical Tests ◽  
Steep Slopes

Abstract. The evaluation of potential mass wasting in mountain areas is a very complex process because there is not enough information to quantify the probability and magnitude of these events. Identifying the whole chain of events is not a straightforward task, and the impacts of mass wasting processes depend on the conditions downstream of the origin. Additionally, climate change is playing an essential role in the occurrence and distribution. Mean temperatures are continuously rising to produce long term instabilities, particularly on steep slopes. Extreme precipitations events are more recurrent as well as heat waves that can melt snow and glaciers, increasing the water available to unstabilized slopes. In this paper, we present an example that portraits the complexities in the evaluation of the chain of events. On the 16 of December of 2017, a rockslide occurred in the Yelcho mountain range. In that event, 7 million m3 of rocks and soil fell on the Yelcho glacier depositing 2 million m3 on the glacier terminal, and the rest continued downstream, triggering a mudflow that hit Villa Santa Lucia in the Chilean Patagonia, killing 22 people. The rockslide event or similar was anticipated in the region by the National Geological and Mining Survey (Sernageomin in Spanish). However, the effects of the terrain characteristics along the runout area were more significant than what was anticipated. In this work, we evaluate the conditions that enable the mudflow that hits Villa Santa Lucia. We used the information generated by Sernageomin's professional after the mudflow. We carried out geotechnical tests to characterize the soil. We simulated the mudflow using two hydrodynamics software (r-avaflow and Flo-2D) that can handle the rheology of the water–soil mixture. Our results indicate that the soil is classified as volcanic pumices. This type of soil can be susceptible to the collapse of the structure when subjected to shearing (molding), flowing like a viscous liquid. From the numerical modeling, we concluded that r-avaflow performs better than Flo2D. We can reproduce the mudflow satisfactorily using water content in the mixture ranging from 30 to 40 %. Finally, in order to achieve the water content, we need a source of water smaller than 3 million m3 approximately. From the simulations and soil tests, we determined that in the area scoured by the mudflow, there were around 2 789 500 m3 of water within the soil. Therefore, the conditions of the valley were crucial to enhance the impacts of the landslide. This result is relevant because it highlights the importance of evaluating the complete chain of events to map hazards. We suggest that in future hazard mapping, geotechnical studies in combination with hydrodynamic simulation should be included, in particular, when human lives are at risk.

scholarly journals On the shapes of the isogeotherms under mountain ranges in radio-active districts

1910 ◽  
Vol 83 (563) ◽  
pp. 339-346 ◽  
Keyword(s):  
Physical Condition ◽  
Accurate Solution ◽  
Earth’S Crust ◽  
Mountain Range ◽  
Mountain Ranges ◽  
Earth's Crust

The importance attached by geologists to the distribution of temperature within the earth’s crust as a factor in the production of movements of the crust, and in particular in the formation of mountain ranges, has made it necessary to consider if it is possible to determine the distribution of temperature under and in the neighbourhood of a mountain range, by a method more rigid and accurate than that used by Fisher, and more closely following the physical condition of the problem than that used by Thoma. In what follows it will be shown that an accurate solution can be obtained in certain simple cases, even when the soil is radio-active.

On the Synergistic Climatic Effects of Covarying Major Mountain Range Topographies

2020 ◽  
Author(s):  
Sebastian G. Mutz ◽  
Todd A. Ehlers
Keyword(s):  
General Circulation ◽  
Atmospheric Transport ◽  
Circulation Model ◽  
Careful Consideration ◽  
Mountain Range ◽  
Earth Surface ◽  
Climatic Effects ◽  
Climate Conditions ◽  
Mountain Ranges ◽  
The Impact

<p>The interpretation of Earth surface archives often requires consideration of distant off-site events. One such event is the surface uplift of Earth’s major mountain ranges, which affects climate and the Earth’s surface globally. In this study, the individual and synergistic climatic effects of topographic changes in major mountain ranges are explored with a series of General Circulation Model (GCM) experiments and analyses of atmospheric teleconnections. The GCM experiments are forced with different topographic scenarios for Himalaya-Tibet (TBT) and the Andes (ADS), while environmental boundary conditions are kept constant. The topographic scenarios are constructed by successively lowering modern topography to 0% of its modern height in increments of 25%. This results in a total of 5 topographic scenarios for TBT (tbt100, tbt075, tbt050, tbt025, tbt000) and ADS (ads100, ads075, ads050, ads025, ads000). TBT scenarios are then nested in ADS scenarios, resulting in a total of 25 experiments with unique topographic settings. The climate for each of those 25 scenarios is simulated with the GCM ECHAM5-wiso. We then explore possible synergies and distant impacts of topographic changes by testing the hypothesis that varying ADS has no effect on simulated climate conditions in the TBT region (c_tbt) and vice versa. This can be expressed as the null hypothesis c_tbt(ads100) = c_tbt(ads075) = c_tbt(ads050) = c_tbt(ads025) = c_tbt(ads000) for each of the 5 TBT scenarios, and vice versa. We conduct Kruskal-Wallis tests for a total of 10 treatment sets to address these hypotheses. The results suggest that ADS climate is mostly independent of TBT topography changes, whereas TBT climate is sensitive to ADS topography changes when TBT topography is high, but insensitive when TBT topography is strongly reduced. Analyses of atmospheric pressure fields suggest that TBT height acts as a control on cross-equatorial atmospheric transport and modifies the impact of ADS topography on northern hemisphere climate. These results dictate a more careful consideration of global (off-site) conditions in the interpretation of Earth surface records.</p>

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