scholarly journals Surge dynamics on Bering Glacier, Alaska, in 2008–2011

2012 ◽  
Vol 6 (6) ◽  
pp. 1251-1262 ◽  
Author(s):  
E. W. Burgess ◽  
R. R. Forster ◽  
C. F. Larsen ◽  
M. Braun

Abstract. A surge cycle of the Bering Glacier system, Alaska, is examined using observations of surface velocity obtained using synthetic aperture radar (SAR) offset tracking, and elevation data obtained from the University of Alaska Fairbanks LiDAR altimetry program. After 13 yr of quiescence, the Bering Glacier system began to surge in May 2008 and had two stages of accelerated flow. During the first stage, flow accelerated progressively for at least 10 months and reached peak observed velocities of ~ 7 m d−1. The second stage likely began in 2010. By 2011 velocities exceeded 9 m d−1 or ~ 18 times quiescent velocities. Fast flow continued into July 2011. Surface morphology indicated slowing by fall 2011; however, it is not entirely clear if the surge is yet over. The quiescent phase was characterized by small-scale acceleration events that increased driving stresses up to 70%. When the surge initiated, synchronous acceleration occurred throughout much of the glacier length. Results suggest that downstream propagation of the surge is closely linked to the evolution of the driving stress during the surge, because driving stress appears to be tied to the amount of resistive stress provided by the bed. In contrast, upstream acceleration and upstream surge propagation is not dependent on driving stress evolution.

2012 ◽  
Vol 6 (2) ◽  
pp. 1181-1204 ◽  
Author(s):  
E. W. Burgess ◽  
R. R. Forster ◽  
C. F. Larsen ◽  
M. Braun

Abstract. A 2008–2011 surge of Bering Glacier, Alaska is examined using observations of surface velocity and surface elevation change. Velocity measurements are obtained using synthetic aperture radar (SAR) offset tracking and elevation data are obtained from the University of Alaska Fairbanks LiDAR altimetry program. Bering Glacier began to surge in May 2008 and had two phases of accelerated flow. The first phase accelerated progressively for at least 10 months and reached peak observed velocities of ~7 m d−1. Results suggest that during the quiescent phase, prior to the surge, periods of accelerated flow increased driving stresses up to 70% in a ~10 km-long section of the Lower Bering. When the first phase of the surge initiated, synchronous acceleration occurred throughout much of the glacier length, indicating widespread pressurization of the bed, but the largest accelerations initiated at the location where driving stress built up during quiescence. From there, rapid flow velocities propagated upstream and downstream across much of the glacier length and transpired as small, transient and unorganized propagation fronts. The second phase occurred in 2011 and was of comparable scale to the surge in 1993–1995, with velocities exceeding 9 m d−1 or ~18 times quiescent velocities.


2015 ◽  
Vol 13 (2-3) ◽  
pp. 9-22
Author(s):  
Ian Brodie ◽  
Brian Coyle

This paper reports the findings of a small-scale study undertaken by one university – Glasgow Caledonian University- to test the state of ‘partnership working’ between the university and placement providers. The study was conducted in two stages with 35 practice teachers responding to an on-line survey in stage one, and 16 practice teachers and students participating in interviews at stage 2. Overall findings indicate that the university has managed to sustain effective partnership working, despite organisational changes and resource constraints but that a number of improvements should be made to existing arrangements so that partnership working and the quality of practice learning can be further enhanced. It is evident that ‘independent practice teachers’ and ‘work-based supervisors’ have an increasing presence on the practice learning landscape, requiring a careful examination of their roles and responsibilities.


EduLingua ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Jesús Ángel González ◽  
Javier Barbero Andrés

We report on a small-scale study carried out in the University of Cantabria, Spain, which investigated teaching strategies and methodology for CLIL at the tertiary level. The study was carried out in two stages: in the first one we designed a questionnaire for primary and secondary school teachers, and interviewed 10 CLIL teachers. The focus was on teaching strategies and methodology, with the explicit aim of collecting advice applicable to the tertiary level. In the second stage we have tested these tips in a university context through a second questionnaire and round of interviews. We have interviewed 10 EMI university lecturers and asked them about methodological strategies, and specifically about the advice suggested by their colleagues. Our findings suggest that CLIL teachers from lower levels are well acquainted with CLIL methodology and that EMI practitioners at university find their advice very useful, although they show reluctance towards deeper methodological changes.


2021 ◽  
Vol 13 (12) ◽  
pp. 2293
Author(s):  
Marina Amadori ◽  
Virginia Zamparelli ◽  
Giacomo De Carolis ◽  
Gianfranco Fornaro ◽  
Marco Toffolon ◽  
...  

The SAR Doppler frequencies are directly related to the motion of the scatterers in the illuminated area and have already been used in marine applications to monitor moving water surfaces. Here we investigate the possibility of retrieving surface water velocity from SAR Doppler analysis in medium-size lakes. ENVISAT images of the test site (Lake Garda) are processed and the Doppler Centroid Anomaly technique is adopted. The resulting surface velocity maps are compared with the outputs of a hydrodynamic model specifically validated for the case study. Thermal images from MODIS Terra are used in support of the modeling results. The surface velocity retrieved from SAR is found to overestimate the numerical results and the existence of a bias is investigated. In marine applications, such bias is traditionally removed through Geophysical Model Functions (GMFs) by ascribing it to a fully developed wind waves spectrum. We found that such an assumption is not supported in our case study, due to the small-scale variations of topography and wind. The role of wind intensity and duration on the results from SAR is evaluated, and the inclusion of lake bathymetry and the SAR backscatter gradient is recommended for the future development of GMFs suitable for lake environments.


2008 ◽  
Vol 604 ◽  
pp. 165-174 ◽  
Author(s):  
XAVIER CAPET ◽  
PATRICE KLEIN ◽  
BACH LIEN HUA ◽  
GUILLAUME LAPEYRE ◽  
JAMES C. MCWILLIAMS

The relevance of surface quasi-geostrophic dynamics (SQG) to the upper ocean and the atmospheric tropopause has been recently demonstrated in a wide range of conditions. Within this context, the properties of SQG in terms of kinetic energy (KE) transfers at the surface are revisited and further explored. Two well-known and important properties of SQG characterize the surface dynamics: (i) the identity between surface velocity and density spectra (when appropriately scaled) and (ii) the existence of a forward cascade for surface density variance. Here we show numerically and analytically that (i) and (ii) do not imply a forward cascade of surface KE (through the advection term in the KE budget). On the contrary, advection by the geostrophic flow primarily induces an inverse cascade of surface KE on a large range of scales. This spectral flux is locally compensated by a KE source that is related to surface frontogenesis. The subsequent spectral budget resembles those exhibited by more complex systems (primitive equations or Boussinesq models) and observations, which strengthens the relevance of SQG for the description of ocean/atmosphere dynamics near vertical boundaries. The main weakness of SQG however is in the small-scale range (scales smaller than 20–30 km in the ocean) where it poorly represents the forward KE cascade observed in non-QG numerical simulations.


Author(s):  
Felipe Ribolla Masetti ◽  
Pedro Cardozo de Mello ◽  
Guilherme F. Rosetti ◽  
Eduardo A. Tannuri

This paper presents small-scale low-speed maneuvering tests with an oceanographic research vessel and the comparison with mathematical model using the real time maneuvering simulator developed by the University of São Paulo (USP). The tests are intended to verify the behavior of the vessel and the mathematical model under transient and low speed tests. The small-scale tests were conducted in deep and shallow waters, with a depth-draft ratio equal to 1.28, in order to verify the simulator ability to represent the vessel maneuverability on both depth conditions. The hydrodynamic coefficients used in the simulator model were obtained by CFD calculations and wind tunnel model tests carried out for this vessel. Standard turning circle and accelerating turn maneuvers were used to compare the experimental and numerical results. A fair agreement was achieved for shallow and deep water. Some differences were observed mainly in the initial phase of the accelerating turn test.


2013 ◽  
Vol 54 (63) ◽  
pp. 221-228 ◽  
Author(s):  
James Turrin ◽  
Richard R. Forster ◽  
Chris Larsen ◽  
Jeanne Sauber

AbstractBering Glacier, Alaska, USA, has a ∼20 year surge cycle, with its most recent surge reaching the terminus in 2011. To study this most recent activity a time series of ice velocity maps was produced by applying optical feature-tracking methods to Landsat-7 ETM+ imagery spanning 2001-11. The velocity maps show a yearly increase in ice surface velocity associated with the down-glacier movement of a surge front. In 2008/09 the maximum ice surface velocity was 1.5 ±0.017 km a-1 in the mid-ablation zone, which decreased to 1.2 ±0.015 km a-1 in 2009/10 in the lower ablation zone, and then increased to nearly 4.4 ± 0.03 km a-1 in summer 2011 when the surge front reached the glacier terminus. The surge front propagated down-glacier as a kinematic wave at an average rate of 4.4 ±2.0 km a-1 between September 2002 and April 2009, then accelerated to 13.9 ± 2.0 km a-1 as it entered the piedmont lobe between April 2009 and September 2010. The wave seems to have initiated near the confluence of Bering Glacier and Bagley Ice Valley as early as 2001, and the surge was triggered in 2008 further down-glacier in the mid-ablation zone after the wave passed an ice reservoir area.


Author(s):  
Kala Meah ◽  
Steven Fletcher ◽  
Yu Wan ◽  
Sadrul Ula

Many parts of the western US is rural in nature and consequently do not have electrical distribution lines in many parts of farms and ranches. Distribution line extension costs can run from $15,000 to $25,000 per mile, thereby making availability of electricity to small water pumping projects economically unattractive. Solar photo-voltaic (PV) powered water pumping is more cost effective in these small scale applications. Many western states including Wyoming are passing through fifth year of drought with the consequent shortages of water for many applications. Wyoming State Climatologist is predicting a possible 5–10 years of drought. Drought impacts the surface water right away, while it takes much longer to impact the underground aquifers. To mitigate the effect on the livestock and wildlife, Wyoming Governor Dave Freudenthal initiated a solar water pumping initiative in cooperation with the University of Wyoming, County Conservation Districts, Rural Electric Cooperatives, and ranching organizations. Solar water pumping has several advantages over traditional systems; for example, diesel or propane engines require not only expensive fuels, they also create noise and air pollution in many remote pristine areas. Solar systems are environment friendly, low maintenance and have no fuel cost. In this paper the design, installation and performance monitoring of the solar system for small scale remote water pumping will be presented.


2011 ◽  
Vol 1 (1) ◽  
Author(s):  
Marisela Rodríguez Salvador ◽  
Manuel Alejandro Bautista Reyes

This article presents a new methodology that integrates Competitive Technical Intelligence with Blue Ocean Strategy. We explore new business niches taking advantage of the synergy that both areas offer, developing a model based on cyclic interactions through a process developed in two stages: Understanding opportunity that arise from idea formulation to decision making and strategic development. The validity of our approach (first stage) was observed in the evaluation of an exotic fruit, Anacardium Occidentale, in the South of the State of Veracruz, Mexico with the support of the university ITESM, Campus Monterrey. We identified critical factors for success, opportunities and threats. Results confirm the attractiveness of this crop.


2016 ◽  
Vol 4 (1) ◽  
pp. 34
Author(s):  
Muna Aprilianto ◽  
Tomoliyus Tomoliyus

Penelitian ini bertujuan untuk menghasilkan buku pedoman bermain sepakbola untuk meningkatkan aspek psikologis (semangat, gembira, dan disiplin) anak usia 12-13 tahun di Yogyakarta. Penelitian ini merupakan penelitian dan pengembangan yang terdiri atas dua tahapan yaitu tahap penelitian pendahuluan terdiri dari kajian literatur, kajian penelitian relevan, studi lapangan dan tahap pengembangan terdiri perencanaan, validasi ahli, uji skala kecil, dan uji skala besar. Peneliti ini mengambil sampel dari sekolah sepakbola di Yogyakarta. Teknik sampling yang digunakan adalah purposive sampling. Pada uji coba skala kecil dilakukan di SSB Real Madrid melibatkan 10 siswa dan satu orang pelatih. Pada uji coba skala besar dilakukan di dua tempat yaitu di SSB Real Madrid dan SSB Bina Putra Jaya Sleman melibatkan 38 siswa dan dua pelatih. Analsis data dalam penelitian ini menggunakan teknik analisis deskriptif kuantitatif dan kualitatif. Hasil validasi menunjukkan model bermain sepakbola anak usia 12-13 tahun layak untuk diuji cobakan. Berdasarkan Hasil pelaksanaan pada uji coba skala kecil dan besar secara substansi isi dan pelaksanaan tergolong sangat baik. Hasil penilaian efektivitas model tehadap psikologis anak berupa semangat, gembira, dan disiplin mengalami peningkatan: nilai pertemuan kedua lebih tinggi dari pertemuan pertama. Dapat disimpulkan model bermain sepakbola anak usia 12-13 tahun efektif untuk meningkatkan aspek psikologis berupa semangat, gembira, dan disiplin siswa dalam melakukan latihan sepakbola.Kata Kunci: model, bermain, psikologis, sekolah sepakbola Development a playing soccer model to improve the psychological aspects of 12-13 years old children in Yogyakarta AbstractThis research aims to develop a playing soccer model to improve the psychological aspects (spirit, joy, and discipline) of 12-13 years old children in Yogyakarta. This study is a research and development which consists of two stages. The Preliminary research stage and development stage. The Preliminary research stage consisted of a literature review, relevant research studies and field studies. The Development stage consisted of planning, validation expert, small-scale test, and test large scale. The Validation involve three people experts. The sampel of take it from soccer school in Yogyakarta. The small-scale tryout was conducted on 10 students and one coach of Real Madrid Soccer School in Yogyakarta. The large-scale trials were conducted with two soccer school on 38 students and two coach of Yogyakarta Real Madrid Soccer School and Sleman Bina Putra Jaya Soccer School. The resul is a playing soccer model for children aged 12-13 years with the title "Playing Soccer in Practice to Improve Psychological Aspects". Based on the small-scale tryout and the small-scale tryout content implementation aspects are in an excellent category. The Psychological development of students assessment resulting in the form of passion, joy, and discipline in playing soccer show improvement: score of the second meeting is greater than the average score of the first meeting, thus it can be concluded thaat the playing soccer model for children age 12-13 years is effective to improve students’ psychological aspects, including the aspects of spirit, joy, and discipline in doing soccer practice.Keywords: models, play, psychological, soccer school


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