scholarly journals Three-Dimensional Glacier Changes in Geladandong Peak Region in the Central Tibetan Plateau

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1749 ◽  
Author(s):  
Junli Xu ◽  
Donghui Shangguan ◽  
Jian Wang

In this study, contour lines from the topographic maps at a 1:100,000 scale (mapped in 1968), Landsat MSS/TM/OLI images, ASTER images and SPOT 6-7 stereo image pairs were used to study changes in glacier length, area and surface elevation. We summarized the results using the following three conclusions: (1) During the period from 1973 to 2013, glaciers retreated by 412 ± 32 m at a mean retraction rate of 10.3 ± 0.8 m·year−1 and the relative retreat was 5.6 ± 0.4%. The glacier area shrank by 7.5 ± 3.4%, which was larger than the glacier length. In the periods of 1968–2000, 2000–2005 and 2000–2013, the glacier surface elevation change rates were −7.7 ± 1.4 m (−0.24 ± 0.04 m·year−1), −1.9 ± 1.5 m (−0.38 ± 0.25 m·year−1) and −5.0 ± 1.4 m (−0.38 ± 0.11 m·year−1), respectively. The changes in the glacier area and thickness exhibited similar trends, both showing a significant increasing reduction after 2000. (2) Eleven glaciers were identified as surging glaciers. Changes of the mass balance in surging glaciers were stronger than in non-surging glaciers between 1968 and 2013. Changes of area in surging glaciers were weaker than in non-surging glaciers. (3) Increasing temperature was the major cause of glacier thickness reduction and area shrinkage. The increase in precipitation, to a certain extent, inhibited glacial ablation but it did not change the status of the shrinkage in the glacial area and the reduction in the glacier thickness.

Author(s):  
Z. Zhao ◽  
J. X. Zhang ◽  
M. Y. Duan ◽  
G. M. Huang ◽  
S. C. Yang

A pair of SAR images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo SAR and interferometric SAR. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, StereoSAR and InSAR combined adjustment model are constructed, and unify DEM extraction from InSAR and StereoSAR into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of SAR images 1,2 meet the required conditions for InSAR technology, while the other pair of SAR images 3,4 can form stereo image pairs. The phase model is based on InSAR rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in InSAR processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn’t require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne InSAR and StereoSAR data and compared with InSAR and StereoSAR methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.


2014 ◽  
Vol 8 (3) ◽  
pp. 2573-2610 ◽  
Author(s):  
D. Shangguan ◽  
T. Bolch ◽  
Y. Ding ◽  
M. Kröhnert ◽  
T. Pieczonka ◽  
...  

Abstract. Glacier melt is an important source of fresh water for the arid regions surrounding the Tian Shan. Inylchek Glacier (650 km2) is the largest glacier in Tian Shan consisting of two branches (northern Inylchek glacier and southern Inylchek glacier) separated by the regularly draining Lake Merzbacher. However, little is known about volume and mass changes of the last decades. In this study, we investigated the changes of glacier area and glacier surface elevation from 1974 until 2007 and the surface velocity between 2003 and 2011 using multi-temporal remote-sensing data. The main flow direction of Southern Inylchek Glacier tongue showed strong velocities of ∼100 m a−1 with a slight decreasing tendency between 2002/03 and 2010/11. The end of the tongue however, is likely stagnant as the main flow is directed towards Lake Merzbacher. The total glacier area increased by 1.3 ± 0.1 km2 (∼0.2%) within the studies period though southern Inylchek Glacier shrank consecutive since 1974. The overall area gain was caused by the strong increase of northern Inylchek Glacier of 3.7 ± 0.3 km2 between 1990–1999. A comparison of glacier surface elevation using multi-temporal digital elevation models derived from KH9-Hexagon (1974), SRTM (1999), ALOS (2006) and SPOT5-HRG (2007) revealed an overall elevation difference of Inylchek Glacier of −0.5 ± 0.1 m a−1 for the period of 1974–2007. The northern glacier branch showed on average no significant surface elevation change (0.1 ± 0.1 m a−1) during 1974 and 2007 while a significant lowering of 0.7 ± 0.1 m a−1 was observed for the southern branch. The overall negative values are mainly due to the period 1974–1999. A possible thickening of 0.5 ± 0.5 m a−1 occurred between 1999 and 2007 where a clear thickening was measured in the accumulation area of the southern branch. We also identified the thickening with a maximum of about ∼150 m close to the end of the northern Inylchek Glacier tongue for the period 1974–1999. This is possibly due to a surge event which happened between 1990 and 1999 according to the area change data. The ablation region of southern Inylchek Glacier showed considerable lowering rates especially in the distal part of the tongue with low velocity despite thick debris coverage.


Author(s):  
Roger Taylor

The birth of three-dimensional photography was highly controversial with much heated debate and rivalry from its proponents who competed to be first. This chapter highlights the historical background of 3-D by quoting The Great Exhibition of 1850 and the birth of commercial stereoscopic photography. For the first time audiences were introduced to Brewster's stereoscope, allied to Daguerre's photographic images and so successful was public reaction that by 1852 the system had become a commercial triumph with much to be gained. During the following decade the new steam railway network rapidly engulfed much of the British Isles and Europe, making the distribution of mass replicated stereo-views within easy reach for many. Indeed entrepreneurs, such as John Nottage, commissioned sets of stereo-views and built a catalogue of more than 10,000 stereo image pairs that are still highly sought after in todays auction houses. Public interest peaked around 1870 and thereafter began to decline, due in part to the stereo photograph, or pair, becoming ubiquitous. Roger Taylor offers a glimpse into that period of history when enthusiasm for the stereo photograph has never been surpassed.


2020 ◽  
Vol 64 (2) ◽  
pp. 20506-1-20506-7
Author(s):  
Min Zhu ◽  
Rongfu Zhang ◽  
Pei Ma ◽  
Xuedian Zhang ◽  
Qi Guo

Abstract Three-dimensional (3D) reconstruction is extensively used in microscopic applications. Reducing excessive error points and achieving accurate matching of weak texture regions have been the classical challenges for 3D microscopic vision. A Multi-ST algorithm was proposed to improve matching accuracy. The process is performed in two main stages: scaled microscopic images and regularized cost aggregation. First, microscopic image pairs with different scales were extracted according to the Gaussian pyramid criterion. Second, a novel cost aggregation approach based on the regularized multi-scale model was implemented into all scales to obtain the final cost. To evaluate the performances of the proposed Multi-ST algorithm and compare different algorithms, seven groups of images from the Middlebury dataset and four groups of experimental images obtained by a binocular microscopic system were analyzed. Disparity maps and reconstruction maps generated by the proposed approach contained more information and fewer outliers or artifacts. Furthermore, 3D reconstruction of the plug gauges using the Multi-ST algorithm showed that the error was less than 0.025 mm.


2011 ◽  
Vol 267 ◽  
pp. 217-220 ◽  
Author(s):  
Jiang Tian Shi ◽  
De Xin Sun ◽  
Hong Zhuang Zhang

Mechanical structure of three degree of freedoms SCARA robot adopts horizontal joints, and opening PMAC multitude axis motion controller based PC is looked as kernel of control system, adopts the open hardware and software structure, we can conveniently enlarge its functions according to needs, so it has very good expansibility. Its three-dimensional solid model and virtual assemble is carried out using CATIA application, so that we can estimate the status of interference. Through validation, we can prove the feasibility of the robot.


2006 ◽  
Vol 18 (6) ◽  
pp. 1441-1471 ◽  
Author(s):  
Christian Eckes ◽  
Jochen Triesch ◽  
Christoph von der Malsburg

We present a system for the automatic interpretation of cluttered scenes containing multiple partly occluded objects in front of unknown, complex backgrounds. The system is based on an extended elastic graph matching algorithm that allows the explicit modeling of partial occlusions. Our approach extends an earlier system in two ways. First, we use elastic graph matching in stereo image pairs to increase matching robustness and disambiguate occlusion relations. Second, we use richer feature descriptions in the object models by integrating shape and texture with color features. We demonstrate that the combination of both extensions substantially increases recognition performance. The system learns about new objects in a simple one-shot learning approach. Despite the lack of statistical information in the object models and the lack of an explicit background model, our system performs surprisingly well for this very difficult task. Our results underscore the advantages of view-based feature constellation representations for difficult object recognition problems.


Resources ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 65 ◽  
Author(s):  
Nicoletta Patrizi ◽  
Valentina Niccolucci ◽  
Riccardo Pulselli ◽  
Elena Neri ◽  
Simone Bastianoni

One of the main goals of any (sustainability) indicator should be the communication of a clear, unambiguous, and simplified message about the status of the analyzed system. The selected indicator is expected to declare explicitly how its numerical value depicts a situation, for example, positive or negative, sustainable or unsustainable, especially when a comparison among similar or competitive systems is performed. This aspect should be a primary and discriminating issue when the selection of a set of opportune indicators is operated. The Ecological Footprint (EF) has become one of the most popular and widely used sustainability indicators. It is a resource accounting method with an area based metric in which the units of measure are global hectares or hectares with world average bio-productivity. Its main goal is to underline the link between the (un)sustainability level of a product, a system, an activity or a population life style, with the land demand for providing goods, energy, and ecological services needed to sustain that product, system, activity, or population. Therefore, the traditional rationale behind the message of EF is: the larger EF value, the larger environmental impact in terms of resources use, the lower position in the sustainability rank. The aim of this paper was to investigate if this rationale is everywhere opportune and unambiguous, or if sometimes its use requires paying a special attention. Then, a three-dimensional modification of the classical EF framework for the sustainability evaluation of a product has been proposed following a previous work by Niccolucci and co-authors (2009). Finally, the potentialities of the model have been tested by using a case study from the agricultural context.


MRS Bulletin ◽  
2008 ◽  
Vol 33 (6) ◽  
pp. 597-602 ◽  
Author(s):  
G. Spanos ◽  
D.J. Rowenhorst ◽  
A.C. Lewis ◽  
A.B. Geltmacher

AbstractThis article first provides a brief review of the status of the subfield of three-dimensional (3D) materials analyses that combine serial sectioning, electron backscatter diffraction (EBSD), and finite element modeling (FEM) of materials microstructures, with emphasis on initial investigations and how they led to the current state of this research area. The discussions focus on studies of the mechanical properties of polycrystalline materials where 3D reconstructions of the microstructure—including crystallographic orientation information—are used as input into image-based 3D FEM simulations. The authors' recent work on a β-stabilized Ti alloy is utilized for specific examples to illustrate the capabilities of these experimental and modeling techniques, the challenges and the solutions associated with these methods, and the types of results and analyses that can be obtained by the close integration of experiments and simulations.


Author(s):  
Вячеслав Иванович Моисеев

В статье даётся краткий очерк антиномической природы биоэтического дискурса и возможностей его геометрической визуализации. Рассматриваются два варианта визуализации. Первый связан с представлением той или иной ситуации как системы полярностей, которая в свою очередь моделируется в рамках векторной модели. В простейшем случае тезис и антитезис рассматриваются как два перпендикулярных вектора, а синтез – как их векторная сумма. В этом случае можно ввести и более количественную оценку «меры многомерности» полярной системы – как величины проекции её векторного представления на суммарный вектор. С использованием этих конструкций разбирается один пример из биоэтики, связанный со столкновением принципов милосердия и правдивости (проблема «лжи во спасение»). Деяние (действие или бездействие) интерпретируется как своеобразный оператор на событиях, который переводит одни события в другие. Предполагается, что субъект в своих деяниях рассматривает различные возможности и выбирает те из них, которые максимизируют ту или иную ценностную меру субъекта, в данном случае – меру векторной проекции полярного вектора ситуации на суммарный вектор – вектор синтеза базисных полярностей. Второй вариант визуализации связан с понятием антиномий в биоэтике – таких противоречий, которые не являются формально-логическими ошибками. В отличие от последних, в антиномиях как тезис, так и антитезис имеют свой момент оправдания в рамках тех или иных условий. Используется также понятие «антинома» – логического субъекта антиномии, который предицируется тезисом и антитезисом антиномии. Редукции антиномии соответствуют двум крайним аспектам антинома, которые называются его «редуктами» – по аналогии с редукцией волновой функции в квантовой механике. Приводятся различные примеры антиномов: биоэты, глоболоки, холомеры. В биоэтах один редукт выражает в большей мере биологические (биоредукт), второй – этические (эторедукт) определения антинома. В глоболоках выделяются глобальный (глоборедукт) и локальный (локоредукт) виды редуктов: первый выражает более глобальные (универсальные) этические определения, второй – более локальные, связанные с ценностями и нормами того или иного сообщества. Наконец, холомеры – вид антиномов, где антиномически соединяются определения целого (холоредукт) и части (мероредукт). Даётся их интерпретация как многомерных ментальных объектов в некотором обобщённом пространстве, так что крайние их аспекты (редукции антиномии) можно представить как проекции более многомерного состояния. В заключении делается предположение о связи биоэтических проблем с идеей ментальной многомерности, что составляет основу возможной визуализации как интерпретации ментальной многомерности на векторном её представлении. The article provides a brief outline of the antinomic nature of bioethical discourse and the possibilities of its geometric visualization. Two visualization options are considered. The first is associated with the representation of a particular situation as a system of polarities, which in turn is modeled in the framework of a vector model. In the simplest case, the thesis and the antithesis are considered as two orthogonal vectors P1 and P2, and the synthesis is considered as their vector sum S = P1+P2. In this case, we can also introduce a more quantitative estimate of the “measure of multidimensionality” M(P) of the polar system – as the magnitude of the projection of its vector representation P on the sum vector S, i.e. M(P) = (P,es), where es = S/|S| is the unit vector of the vector S, and (P,es) is the scalar product of the vectors P and es. Using these constructs, the author analyzes one example from bioethics related to the clash of the principles of mercy and truthfulness (the problem of “lying for salvation”). An act (action or omission) is interpreted as a kind of an operator on events that transforms some events into others. It is assumed that the subject considers various possibilities in their actions and chooses those that maximize a particular value measure of the subject, in our case, the measure M(P) of the vector projection of the polar vector P of the situation on the sum vector S – the vector of synthesis of basic polarities. The second version of visualization is related to the concept of antinomies – such contradictions that are not formal logical errors – in bioethics. In contrast to errors, in antinomies, both the thesis and the antithesis have their moment of justification within the framework of certain conditions. The concept “antinome” is also used; it is the logical subject of antinomy, which is predicated by the thesis and the antithesis of antinomy. Antinomy reductions correspond to two extreme aspects of the antinome, which are called its “reducts” – by analogy with the reduction of the wave function in quantum mechanics. Various examples of antinomes are given: bioets, globolocs, and holomers. In bioets, one reduct expresses the biological (bioreduct) definition of the antinome, another the ethical (ethoreduct) one. In globolocs, global (globoreduct) and local (locoreduct) types of reducts are distinguished: the former expresses more global (universal) ethical definitions, the latter more local ones, related to the values and norms of a particular local community. Finally, holomers are a kind of antinomes in which the definitions of the whole (holoreduct) and the part (meroreduct) are antinomically connected. They are interpreted as multidimensional mental objects in some generalized space, so that their extreme aspects (antinomy reductions) can be represented as generalized projections of a more multidimensional state within certain constricted conditions (reduction intervals). In this case, it is possible to geometrically visualize such states as, for example, three-dimensional objects in space, through which antinomes can be modeled, and their reducts as two-dimensional projections of a three-dimensional body on certain projection planes (intervals of reducts). In this case, one of the central tasks of bioethics is to determine the boundaries of the demarcation of some intervals from others. For example, in solving the problem of abortion and the status of the human embryo, such a demarcation is expressed in the search for a time point that would separate the phase of a more biological definition (bioreduct) of the embryo from its more ethical state (ethoreduct). In conclusion, the author suggests that bioethical problems are connected with the idea of mental multidimensionality, which forms the basis of a possible visualization as an interpretation of mental multidimensionality in its vector representation.


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