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Author: Jakob Griebel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Sea ice is a key component of the climate system since it regulates the exchange of heat, the moisture, and the salinity in the polar oceans. The sea ice cover is set into motion and drifts, deforms and fractures under the action of external forces and respective boundary conditions. A positive trend in sea ice mobility, differential kinematics and deformation has been observed in the last decades. This increasing dynamics can increase the ice-albedo feedback loop, one of the most important feedback mechanisms related to climate change. The kinematics of sea ice is observed from space by synthetic aperture radar (SAR) and quantified using drift detection algorithms. The requirements that the applied algorithm has to meet regarding resolution, reliability and computing time vary with the type of application. Sea ice kinematics and associated deformation processes occur across a wide range of spatial scales, from meters to thousands of kilometers. It is important to understand how large-scale behavior monitored by satellite relates to and depends on small scale processes of sea ice. Thus, the major objective of this study was to review and validate recent research results of sea ice drift and deformation characteristics obtained at larger scales by extending the analyzes towards smaller scales and examine emerging difficulties and challenges.
Author: Jakob Griebel
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Sea ice is a key component of the climate system since it regulates the exchange of heat, the moisture, and the salinity in the polar oceans. The sea ice cover is set into motion and drifts, deforms and fractures under the action of external forces and respective boundary conditions. A positive trend in sea ice mobility, differential kinematics and deformation has been observed in the last decades. This increasing dynamics can increase the ice-albedo feedback loop, one of the most important feedback mechanisms related to climate change. The kinematics of sea ice is observed from space by synthetic aperture radar (SAR) and quantified using drift detection algorithms. The requirements that the applied algorithm has to meet regarding resolution, reliability and computing time vary with the type of application. Sea ice kinematics and associated deformation processes occur across a wide range of spatial scales, from meters to thousands of kilometers. It is important to understand how large-scale behavior monitored by satellite relates to and depends on small scale processes of sea ice. Thus, the major objective of this study was to review and validate recent research results of sea ice drift and deformation characteristics obtained at larger scales by extending the analyzes towards smaller scales and examine emerging difficulties and challenges.
Author: Tom Carrieres
Publisher: Cambridge University Press
ISBN: 1108417426
Category : Science
Languages : en
Pages : 263
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Book Description
A comprehensive overview of the science involved in automated prediction of sea ice, for sea ice analysts, researchers, and professionals.
Author: Ola M. Johannessen
Publisher: Springer Science & Business Media
ISBN: 3540488405
Category : Science
Languages : en
Pages : 564
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Book Description
Remote Sensing of Sea Ice in the Northern Sea Route: Studies and Applications initially provides a history of the Northern Sea Route as an important strategic transport route for supporting the northern regions of Russia and cargo transportation between Europe and the Northern Pacific Basin. The authors then describe sea ice conditions in the Eurasian Arctic Seas and, using microwave satellite data, provide a detailed analysis of difficult sea ice conditions. Remote sensing techniques and the basic principles of SAR image formation are described, as well as the major satellite radar systems used for ice studies in the Arctic. The authors take a good look at the use of sensing equipment in experiments, including the ICE WATCH project used for monitoring the Northern Sea Route. The possibilities of using SAR remote sensing for ice navigation in the Northern Sea Route is also detailed, analysing techniques of automatic image processing and interpretation. A study is provided of regional drifting ice, fast ice and river ice in the coastal areas of the Arctic Seas. The book concludes with a review of the practical experience using SAR images for supporting navigation and offshore industrial activity, based on a series of experiments conducted with the Murmansk Shipping Company on board nuclear icebreakers.
Author: Jean-Jacques Rousseau
Publisher: Springer Nature
ISBN: 3031377311
Category : Computers
Languages : en
Pages : 652
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Book Description
This 4-volumes set constitutes the proceedings of the ICPR 2022 Workshops of the 26th International Conference on Pattern Recognition Workshops, ICPR 2022, Montreal, QC, Canada, August 2023. The 167 full papers presented in these 4 volumes were carefully reviewed and selected from numerous submissions. ICPR workshops covered domains related to pattern recognition, artificial intelligence, computer vision, image and sound analysis. Workshops’ contributions reflected the most recent applications related to healthcare, biometrics, ethics, multimodality, cultural heritage, imagery, affective computing, etc.
Author: Matti Leppäranta
Publisher: Springer Science & Business Media
ISBN: 3540269703
Category : Science
Languages : en
Pages : 282
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Book Description
This book presents the fundamental laws of sea ice drift, as derived from the material properties of sea ice, the basic laws of mechanics, and the latest modeling techniques. Topics covered include the science of sea ice drift, forecasting velocity based on volume, size and shape, sea ice ridging and remote sensing, modelling of ice conditions, and the role of sea ice drift in oceanography, marine ecology and engineering.
Author: Jerome Weiss
Publisher: Springer Science & Business Media
ISBN: 940076202X
Category : Science
Languages : en
Pages : 95
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Book Description
Sea ice is a major component of polar environments, especially in the Arctic where it covers the entire Arctic Ocean throughout most of the year. However, in the context of climate change, the Arctic sea ice cover has been declining significantly over the last decades, either in terms of its concentration or thickness. The sea ice cover evolution and climate change are strongly coupled through the albedo positive feedback, thus possibly explaining the Arctic amplification of climate warming. In addition to thermodynamics, sea ice kinematics (drift, deformation) appears as an essential factor in the evolution of the ice cover through a reduction of the average ice age (and consequently of the cover's thickness), or ice export out of the Arctic. This is a first motivation for a better understanding of the kinematical and mechanical processes of sea ice. A more upstream, theoretical motivation is a better understanding of the brittle deformation of geophysical objects across a wide range of scales. Indeed, owing to its very strong kinematics, compared e.g. to the Earth’s crust, an unrivaled kinematical data set is available for sea ice from in situ (e.g. drifting buoys) or satellite observations. Here, we review the recent advances in the understanding of sea ice drift, deformation and fracturing obtained from these data. We focus particularly on the scaling properties in time and scale that characterize these processes, and we emphasize the analogies that can be drawn from the deformation of the Earth’s crust. These scaling properties, which are the signature of long-range elastic interactions within the cover, constrain future developments in the modeling of sea ice mechanics. We also show that kinematical and rheological variables such as average velocity, average strain-rate or strength have significantly changed over the last decades, accompanying and actually accelerating the Arctic sea ice decline.
Author: Matti Leppäranta
Publisher: Springer Science & Business Media
ISBN: 3642046835
Category : Science
Languages : en
Pages : 370
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Book Description
The Second Edition of The Drift of Sea Ice presents the fundamental laws of sea ice drift which come from the material properties of sea ice and the basic laws of mechanics. The resulting system of equations is analysed for the general properties of sea ice drift, the free drift model and analytical models for ice drift in the presence of internal friction, and the construction of numerical ice drift models is detailed. This second edition of a much lauded work, unique on this topic in the English language, has been revised, updated and expanded with much new information and outlines recent results, in particular in relation to the climate problem, mathematical modelling and ice engineering applications. The current book presents the theory, observations, mathematical modelling techniques, and applications of sea ice drift science. The theory is presented from the beginning on a graduate student level, so that students and researchers coming from other fields such as physical oceanography, meteorology, physics, engineering, environmental sciences or geography can use the book as a source book or self-study material. First the drift ice material is presented ending with the concept of ‘ice state’ – the relevant properties in sea ice dynamics. Ice kinematics observations are widely presented with the mathematical analysis methods, and thereafter come drift ice rheology – to close the triangle material – kinematics – stress. The momentum equation of sea ice is derived in detail and its general properties are carefully analysed. Then follow two chapters on analytical models: free drift and drift in the presence of internal friction: These are very important tools in understanding the dynamical behaviour of sea ice. The last topical chapter is numerical models, which are the modern tool to solve ice dynamics problem in short term and long term problems. The closing chapter summarises sea ice dynamics applications and the need of sea ice dynamic knowledge and gives some final remarks on the future of this branch of science.
Author: Mohammed Shokr
Publisher: John Wiley & Sons
ISBN: 1119027969
Category : Science
Languages : en
Pages : 1464
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Book Description
Sea Ice: Physics and Remote Sensing addresses experiences acquired mainly in Canada by researchers in the fields of ice physics and growth history in relation to its polycrystalline structure as well as ice parameters retrieval from remote sensing observations. The volume describes processes operating at the macro- and microscale (e.g., brine entrapment in sea ice, crystallographic texture of ice types, brine drainage mechanisms, etc.). The information is supported by high-quality photographs of ice thin-sections prepared from cores of different ice types, all obtained by leading experts during field experiments in the 1970s through the 1990s, using photographic cameras and scanning microscopy. In addition, this volume presents techniques to retrieve a suite of sea ice parameters (e.g. ice type, concentration, extent, thickness, surface temperature, surface deformation, etc.) from space-borne and airborne sensor data. The breadth of the material on this subject is designed to appeal to researchers and users of remote sensing data who want to develop quick familiarity with the capabilities of this technology or detailed knowledge about major techniques for retrieval of key ice parameters. Volume highlights include: Detailed crystallographic classification of natural sea ice, the key information from which information about ice growth conditions can be inferred. Many examples are presented with material to support qualitative and quantitative interpretation of the data. Methods developed for revealing microstructural characteristics of sea ice and performing forensic investigations. Data sets on radiative properties and satellite observations of sea ice, its snow cover, and surrounding open water. Methods of retrieval of ice surface features and geophysical parameters from remote sensing observations with a focus on critical issues such as the suitability of different sensors for different tasks and data synergism. Sea Ice: Physics and Remote Sensing is intended for a variety of sea ice audiences interested in different aspects of ice related to physics, geophysics, remote sensing, operational monitoring, mechanics, and cryospheric sciences.
Author: John Alexander Casey
Publisher:
ISBN:
Category :
Languages : en
Pages : 135
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Book Description
Observations of sea ice from space are routinely used to monitor sea ice extent, concentration and type to support human marine activity and climate change studies. In this study, eight dual-polarization (dual-pol) (HH/HV) RADARSAT-2 ScanSAR images acquired over the Gulf of St. Lawrence during the winter of 2009 are analysed to determine what new or improved sea ice information is provided by dual-pol C-band synthetic aperture radar (SAR) data at wide swath widths, relative to single co-pol data. The objective of this study is to assess how dual-pol RADARSAT-2 ScanSAR data might improve operational ice charts and derived sea ice climate data records. In order to evaluate the dual-pol data, ice thickness and surface roughness measurements and optical remote sensing data were compared to backscatter signatures observed in the SAR data. The study found that: i) dual-pol data provide improved separation of ice and open water, particularly at steep incidence angles and high wind speeds; ii) the contrast between new, young and first-year (FY) ice types is reduced in the cross-pol channel; and iii) large areas of heavily deformed ice can reliably be separated from level ice in the dual-pol data, but areas of light and moderately ridged ice cannot be resolved and the thickness of heavily deformed ice cannot be determined. These results are limited to observations of new, young and FY ice types in winter conditions. From an operational perspective, the improved separation of ice and open water will increase the accuracy of ice edge and total ice concentration estimates while reducing the time required to produce image analysis charts. Further work is needed to determine if areas of heavily ridged ice can be separated from areas of heavily rafted ice based on knowledge of ice conditions in the days preceding the formation of high backscatter deformed ice. If rafted and ridged ice can be separated, tactical ridged ice information should be included on image analysis charts. The dual-pol data can also provide small improvements to ice extent and concentration data in derived climate data records. Further analysis of dual-pol RADARSAT-2 ScanSAR data over additional ice regimes and seasons is required.
Author: Nazanin Asadi
Publisher:
ISBN:
Category : Sea ice
Languages : en
Pages : 117
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Book Description
Accurate estimates of sea ice conditions such as ice thickness and ice concentration in the ice-covered regions are critical for shipping activities, ice operations and weather forecasting. The need for this information has increased due to the recent record of decline in Arctic ice extent and thinning of the ice cover, which has resulted in more shipping activities and climate studies. Despite the extensive studies and progress to improve the quality of sea ice forecasts from prognostic models, there is still significant room for improvement. For example, ice-ocean models have difficulty estimating the ice thickness distribution accurately. To help improve model forecasts, data assimilation is used to combine observational data with model forecasts and produce more accurate estimates. The assimilation of ice thickness observations, compared to other ice parameters such as ice concentration, is still relatively unexplored since the satellite-based ice thickness observations have only recently become common. Also, preserving sharp features of ice cover, such as leads and ridges, can be difficult, due to the spatial correlations in the background error covariance matrices. At the same time, the current ice concentration assimilation systems do not directly assimilate high resolution sea ice information from synthetic aperture radar (SAR), even though they are the main source of information for operational production of ice chart products at the Canadian Ice Service. The key challenge in SAR data assimilation is automating the interpretation of SAR images. To address the problem of assimilating ice thickness observations while preserving sharp features, two different objective functions are studied. One with a conventional l2-norm and one imposing an additional l1-norm on the derivative of the ice thickness state estimate as a sparse regularization. The latter is motivated by analysis of high resolution ice thickness observations derived from an airborne electromagnetic sensor demonstrating the sparsity of the ice thickness in the derivative domain. The data fusion and data assimilation experiments are performed over a wide range of background and observation error correlation length scales. Results demonstrate the superiority of using a combined l1-l2 regularization framework especially when the background error correlation length scale was relatively short (approximately five times the analysis grid spacing). The problem of automated information retrieval from SAR images has been explored in a problem of ice/water classification. The selected classification approach takes advantage of neural networks to produce results comparable to a previous study using logistic regression. The employed dataset in both studies is a comprehensive dataset consisting of 15405 SAR images over a seven year period, covering all months and different locations. In addition, recent neural network uncertainty estimation approaches are employed to estimate the uncertainty associated with the classification of ice/water labels, which was not explored in this problem domain previously. These predicted uncertainties can improve the automated classification process by identifying regions in the predictions that should be checked manually by an analyst.
