Difference between pages "IC SG9" and "JSG T.33"

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<big>'''Future developments of ITRF models and their geophysical interpretation'''</big>
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<big>'''JSG 0.20: Space weather and ionosphere'''</big>
  
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Chair: ''A. Dermanis (Greece)''<br>
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Chair: '': Klaus Börger (Germany)''<br>
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Affiliation:''Comm. 1 and IERS''
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Affiliation:''Commissions 1, 4 and GGOS''
  
 
__TOC__
 
__TOC__
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===Terms of Reference===
 
===Terms of Reference===
  
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The realization of a reference system by means of a refer-ence frame, in the form of coordinate time series or coor-dinate functions for a global set of control stations is a complicated procedure. It involves input data from various space techniques each one based on its own advanced modelling and observation analysis techniques, as well as, criteria for the optimal selection of the time evolution of the reference frame among all data compatible possibili-ties.
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It is well known that space geodetic methods are under influence of ionospheric refraction, and therefore from the very beginning of these techniques geodesy deals with the ionosphere. In this context sophisticated methods and models have been developed in order to determine, to represent and to predict the ionosphere. Apart from this the ionosphere fits into another issue called „space weather“, which describes the interactions between the constituents of space and earth. To be more precise space weather means the conditions in space with a significant impact on space-based and ground-based technology as well as on earth and its inhabitants.  Solar radiation, that is electromagnetic emission as well as particle emission, is the main cause or “drive” of space weather.
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The relevant “observed” coordinate time series demon-strate significant signals of periodic, non-periodic varia-tions and discontinuities, which pose the challenge of departing from the current ITRF model of linear time evo-lution, realized by reference epoch coordinates and con-stant velocities.
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Originally, geodesy, or to be more precise, space geodetic methods have considered the ionosphere as a disturbing factor that affects signal propagation and that has to be corrected. This (geodetic) perspective has been changed over time and the ionosphere has become a target value so that geodetic observations are used to determine the ionosphere. Different groups have developed models of high quality, e.g. 3D-models which describe the ionosphere as a function of longitude, latitude and time or even 4D-models accounting for the height as well. However, since the ionosphere is a manifestation of space weather, geodesy should contribute to space weather research, and in this respect completely new scientific questions arise, in particular with respect to the so called “geo-effect”, which is the impact of space weather in general.
  
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The remaining residual signal in coordinate variations is dominated by an almost periodic term with varying amplitude and phase, especially in the height component. The inclusion of additional terms in the ITRF model is an intricate problem that deserves further research and careful planning.
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There are two principal goals of the proposed study group. First, to connect the “geodetic” ionosphere research with solar-terrestrial physics, in order to consider the complete cause-effect-chain. Second, the above mentioned “geo-effect” has to be investigated in detail, which is an important aspect, because modern society depends to a great extent on technology, i.e. technology that can be disturbed, that can be harmed or that even can be destroyed by extreme space weather events
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It is also important to understand the nature of these coor-dinate variations in order to adopt models that are mean-ingful from the geophysical point of view and not a simple fit to the observed data.
 
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Since geophysical processes causing coordinate variations also cause variations in the gravity field, it is worthwhile to investigate the possibility of incorporating result results from space gravity missions in ITRF modelling.
 
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The working group is primarily aiming in identification of new ITRF models, investigation of their performance and motivation of relevant scientific research.
 
  
 
===Objectives===
 
===Objectives===
  
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* Geophysical interpretation of non-linear coordinate variations and sevelopement of relevant models
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* improvements and enlargements of ionosphere models (including scintillations)
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* Extension of ITRF beyond the current linear (constant velocity) model, treatment of periodic and discontinuous station coordinate time series and establishment of proper procedures for estimation of extended ITRF parameters and quality assessment of the obtained results.
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* geodetic contributions to investigate the impact of space weather/the ionosphere (extreme events) on satellite motion
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* geodetic contributions to investigate the impact of space weather/the ionosphere (extreme events) on communication
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* investigations of the impact of space weather/the ionosphere (extreme events) on remote sensing products
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* investigations of the impact of space weather/the ionosphere (extreme events) on terrestrial technical infrastructure (metallic networks, power grids)
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* “geodetic observations” of currents (ring current, electrojets)
  
 
===Program of activities===
 
===Program of activities===
  
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* Launching of a web-page for dissemination of informa-tion, presentation, communication, outreach purposes, and providing a bibliography.
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* the maintaining of a website for general information as well as for internal exchange of data sets and results
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* Working meetings at international symposia and pre-sentation of research results in appropriate sessions.
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* organization of a workshop w.r.t. space weather and geo-effects
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* Organization of workshops dedicated mainly to problem identification and motivation of relevant scientific research.
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* publication of important findings
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* Organization of a second IAG School on Reference Frames.
 
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===Membership===
 
===Membership===
  
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'' '''Dermanis (Greece), chair'''<br /> Z. Altamimi (France)<br /> X. Collilieux (France)<br /> H. Drewes (Germany)<br /> F. Sansò (Italy)<br />T. van Dam (Luxembourg)<br/>''
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'' '''Klaus Börger (Germany), chair''' <br /> Mahmut Onur Karsioglu (Turkey), vice-chair <br /> Michael Schmidt (Germany) <br /> Jürgen Matzka (Germany) <br /> Barbara Görres (Germany) <br /> George Zhizhao Liu (Hong Kong, China) <br /> Ehsan Forootan (Germany) <br /> Johannes Hinrichs (Germany) <br />''

Revision as of 10:15, 29 April 2016

JSG 0.20: Space weather and ionosphere

Chair: : Klaus Börger (Germany)
Affiliation:Commissions 1, 4 and GGOS

Terms of Reference

It is well known that space geodetic methods are under influence of ionospheric refraction, and therefore from the very beginning of these techniques geodesy deals with the ionosphere. In this context sophisticated methods and models have been developed in order to determine, to represent and to predict the ionosphere. Apart from this the ionosphere fits into another issue called „space weather“, which describes the interactions between the constituents of space and earth. To be more precise space weather means the conditions in space with a significant impact on space-based and ground-based technology as well as on earth and its inhabitants. Solar radiation, that is electromagnetic emission as well as particle emission, is the main cause or “drive” of space weather.

Originally, geodesy, or to be more precise, space geodetic methods have considered the ionosphere as a disturbing factor that affects signal propagation and that has to be corrected. This (geodetic) perspective has been changed over time and the ionosphere has become a target value so that geodetic observations are used to determine the ionosphere. Different groups have developed models of high quality, e.g. 3D-models which describe the ionosphere as a function of longitude, latitude and time or even 4D-models accounting for the height as well. However, since the ionosphere is a manifestation of space weather, geodesy should contribute to space weather research, and in this respect completely new scientific questions arise, in particular with respect to the so called “geo-effect”, which is the impact of space weather in general.

There are two principal goals of the proposed study group. First, to connect the “geodetic” ionosphere research with solar-terrestrial physics, in order to consider the complete cause-effect-chain. Second, the above mentioned “geo-effect” has to be investigated in detail, which is an important aspect, because modern society depends to a great extent on technology, i.e. technology that can be disturbed, that can be harmed or that even can be destroyed by extreme space weather events

Objectives

  • improvements and enlargements of ionosphere models (including scintillations)
  • geodetic contributions to investigate the impact of space weather/the ionosphere (extreme events) on satellite motion
  • geodetic contributions to investigate the impact of space weather/the ionosphere (extreme events) on communication
  • investigations of the impact of space weather/the ionosphere (extreme events) on remote sensing products
  • investigations of the impact of space weather/the ionosphere (extreme events) on terrestrial technical infrastructure (metallic networks, power grids)
  • “geodetic observations” of currents (ring current, electrojets)

Program of activities

  • the maintaining of a website for general information as well as for internal exchange of data sets and results
  • organization of a workshop w.r.t. space weather and geo-effects
  • publication of important findings

Membership

Klaus Börger (Germany), chair
Mahmut Onur Karsioglu (Turkey), vice-chair
Michael Schmidt (Germany)
Jürgen Matzka (Germany)
Barbara Görres (Germany)
George Zhizhao Liu (Hong Kong, China)
Ehsan Forootan (Germany)
Johannes Hinrichs (Germany)

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