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| − | <big>'''Towards cm-accurate geoid - Theories, computational methods and validation'''</big> | + | <big>'''Analysis of complex time series'''</big> |
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| − | Chair: ''Y.M. Wang (USA)''<br> | + | Chair: ''Wiesław Kosek (Poland)''<br> |
| − | Affiliation:''Comm. 2''
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| − | __TOC__
| + | ===Objective=== |
| − | ===Introduction=== | |
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| − | In today's satellite age, the ellipsoidal height can be determined up to 2 cm-accuracy geometrically by the global positioning system (GPS). If geoid models reach the same accuracy, national or global vertical systems can be established in a quick and economical way with cm-accuracy everywhere.
| + | The objective of a study group on "Analysis of complex time series" would |
| − | | + | be to investigate the diverse methodologies and approaches across the |
| − | Geoid modeling has been based on Stokes and Molodensky's theories. In both theories, including the theories of gravity and topographic reductions which are fundamentally important for precise geoid computation, approximations and assumptions are made. The evaluation and verification of the effects of assumptions and approximations in the theories are urgently called for. Due to the massive effort on data collection that has improved our knowledge of the Earth's physical surface and its interior, fixed-boundary value problems become practical and useful. Theoretical and numerical studies along this line are not only important in practice, but also may be a fundamental change in physical geodesy.
| + | geodetic sub-disciplines on time-series analysis. The study group |
| − | | + | membership combines the expertise in time series analysis of EOP, |
| − | The working group aims at bringing together scientists concerned with all aspects of the diverse areas of geodetically relevant theory and its applications. Its goal is to provide a framework consisting of theories and computational methods to ensure that cm-accurate geoid is achievable.
| + | GPS-coordinates, sea level, superconducting gravimetry, and so on. The |
| − | | + | ultimate goal would be a consolidation between such methodologies, or at |
| − | ===Objectives===
| + | least recommendations in that direction. |
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| − | Theoretical research related to precise geoid computations; studies of geodetic boundary values problems (free and fixed boundary value problems); development and refinement of gravity/topographic reduction theories; exploration and implementation of numerical methods of partial differential equations for Earth's gravity field determination (e.g., domain decomposition, spectral combination and others).
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| − | In more details, this includes:
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| − | * Studies of the effect of topographic density variations on the Earth's gravity field, especially the geoid.
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| − | * Rigorous yet efficient calculation of the topographic effects, refinement of the topographic and gravity reductions.
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| − | * Studies on harmonic downward continuations.
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| − | * Non-linear effects of the geodetic boundary value problems on the geoid determinations.
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| − | * Optimal combination of global gravity models with local gravity data.
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| − | * Exploration of numerical methods in solving the geodetic boundary value problems (domain decomposition, finite elements, and others)
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| − | * Studies on data requirements, data quality, distribution and sample rate, for a cm- accurate geoid.
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| − | * Studies on the time variations of the geoid caused by geodynamics.
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| − | * Studies on the interdisciplinary approach for marine geoid determination, e.g., research on realization of a global geoid consistent with the global mean sea surface observed by satellites.
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| − | ===Program of activities===
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| − | * Organization of meetings and conferences.
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| − | * Organizing WG meetings or sessions, in coincidence with a larger event, if the presence of working group members appears sufficiently large.
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| − | * Email discussion and electronic exchange.
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| − | * Launching a web page for dissemination of information, expressing aims, objectives, and discussions.
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| − | * Monitoring and reporting activities of working group members and interested external individuals.
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| − | | |
| − | ===Membership===
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| − | '' '''Y.M. Wang, (USA, chair)'''<br /> W. Featherstone, Australia<br /> N. Kühtreiber, Austria<br /> H. Moritz, Austria<br /> M.G. Sideris, Canada<br /> M. Véronneau, Canada<br /> J. Huang, Canada<br /> M. Santos, Canada<br /> J.C. Li, China<br /> D.B. Cao, China<br /> W.B. Shen, China<br /> F. Mao, China<br /> Z. Martinec, Czech Republic<br /> R. Forsberg, Denmark<br /> O. Anderson, Denmark<br /> H. Abd-Elmotaal, Egypt<br /> H. Denker, Germany<br /> B. Heck, Germany<br /> W. Freeden, Germany<br /> J. H. Kwon, Korea<br /> L. Sjöberg, Sweden<br /> D. Roman, USA<br /> J. Saleh, USA<br /> D. Smith USA<br />''
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