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JSG T.33 - Revision history
2024-03-29T01:30:46Z
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Novak: /* Membership */
2020-06-10T10:48:34Z
<p><span dir="auto"><span class="autocomment">Membership</span></span></p>
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<td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 10:48, 10 June 2020</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Membership===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Membership===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'' '''Wieslaw Kosek (Poland), chair ''' <br /> Orhan Akyilmaz (Turkey) <br /> Johannes Boehm (Austria) <br /> Xavier Collilieux (France) <br /> Olivier de Viron (France) <br /> Laura Fernandez (Argentina) <br /> Richard Gross (USA) <br /> Mahmut O. Karslioglu (Turkey) <br /> Anna Kłos (Poland) <br /> Hans Neuner (Germany) <br /> Tomasz Niedzielski (Poland) <br /> Sergei Petrov (Russia) <br /> Waldemar Popiński (Poland) <br /> Michael Schmidt (Germany) <br /> Michel Van Camp (Belgium) <br />  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'' '''Wieslaw Kosek (Poland), chair ''' <br /> Orhan Akyilmaz (Turkey) <br /> Johannes Boehm (Austria) <br /> Xavier Collilieux (France) <br /> Olivier de Viron (France) <br /> Laura Fernandez (Argentina) <br /> Richard Gross (USA) <br /> Mahmut O. Karslioglu (Turkey) <br /> Anna Kłos (Poland) <br /> Hans Neuner (Germany) <br /> Tomasz Niedzielski (Poland) <br /> Sergei Petrov (Russia) <br /> Waldemar Popiński (Poland) <br /> Michael Schmidt (Germany) <br /> Michel Van Camp (Belgium) <br /> Jan Vondrák (Czech Republic) <br /> Dawei Zheng (China) <br /> Yonghong Zhou (China) <br />''</div></td></tr>
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Novak
http://icct.kma.zcu.cz/index.php?title=JSG_T.33&diff=599&oldid=prev
Novak at 10:48, 10 June 2020
2020-06-10T10:48:11Z
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Introduction===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Introduction===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">It is well known that space geodetic methods are under influence </del>of <del class="diffchange diffchange-inline">ionospheric refraction, and therefore from </del>the <del class="diffchange diffchange-inline">very beginning of these </del>techniques <del class="diffchange diffchange-inline">geodesy deals with </del>the <del class="diffchange diffchange-inline">ionosphere. In this context sophisticated methods and models have been developed </del>in <del class="diffchange diffchange-inline">order to determine</del>, <del class="diffchange diffchange-inline">to represent </del>and <del class="diffchange diffchange-inline">to predict </del>the <del class="diffchange diffchange-inline">ionosphere</del>. <del class="diffchange diffchange-inline">Apart from this </del>the <del class="diffchange diffchange-inline">ionosphere fits into another issue called „space weather“, which describes </del>the <del class="diffchange diffchange-inline">interactions </del>between the <del class="diffchange diffchange-inline">constituents of space </del>and <del class="diffchange diffchange-inline">earth</del>. <del class="diffchange diffchange-inline">To be more precise space weather means </del>the <del class="diffchange diffchange-inline">conditions in space with a significant impact on space-based </del>and <del class="diffchange diffchange-inline">ground-based technology as well as on earth and its inhabitants.  Solar radiation</del>, <del class="diffchange diffchange-inline">that is electromagnetic emission as well as particle emission, is </del>the <del class="diffchange diffchange-inline">main cause or “drive” of space weather</del>.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Observations </ins>of the <ins class="diffchange diffchange-inline">space geodesy </ins>techniques <ins class="diffchange diffchange-inline">enable measuring Earth’s gravity variations caused by mass displacement, </ins>the <ins class="diffchange diffchange-inline">change </ins>in <ins class="diffchange diffchange-inline">the Earth’s shape</ins>, and the <ins class="diffchange diffchange-inline">change in the Earth’s rotation</ins>. <ins class="diffchange diffchange-inline">The Earth’s rotation represented by </ins>the <ins class="diffchange diffchange-inline">Earth Orientation Parameters (EOP) should be observed with possibly </ins>the <ins class="diffchange diffchange-inline">smallest latency to provide real-time transformation </ins>between the <ins class="diffchange diffchange-inline">International Terrestrial and Celestial Reference Frames (ITRF </ins>and <ins class="diffchange diffchange-inline">ICRF)</ins>. <ins class="diffchange diffchange-inline">Observed by GRACE missions, redistribution of mass within the fluid layers relative to </ins>the <ins class="diffchange diffchange-inline">solid Earth induces exchange of angular momentum between these layers </ins>and <ins class="diffchange diffchange-inline">solid Earth</ins>, <ins class="diffchange diffchange-inline">changes in </ins>the <ins class="diffchange diffchange-inline">Earth’s inertia tensor</ins>.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">Originally, geodesy, or </del>to <del class="diffchange diffchange-inline">be more precise, space geodetic methods have considered </del>the <del class="diffchange diffchange-inline">ionosphere as a disturbing factor that affects signal propagation </del>and <del class="diffchange diffchange-inline">that has </del>to <del class="diffchange diffchange-inline">be corrected</del>. <del class="diffchange diffchange-inline">This (geodetic) perspective has been changed over time </del>and <del class="diffchange diffchange-inline">the ionosphere has become a target value so that geodetic </del>observations <del class="diffchange diffchange-inline">are used to determine </del>the <del class="diffchange diffchange-inline">ionosphere</del>. <del class="diffchange diffchange-inline">Different groups have developed models </del>of <del class="diffchange diffchange-inline">high quality</del>, <del class="diffchange diffchange-inline">e.g</del>. <del class="diffchange diffchange-inline">3D-models </del>which <del class="diffchange diffchange-inline">describe </del>the <del class="diffchange diffchange-inline">ionosphere as a function </del>of <del class="diffchange diffchange-inline">longitude</del>, <del class="diffchange diffchange-inline">latitude </del>and <del class="diffchange diffchange-inline">time </del>or <del class="diffchange diffchange-inline">even 4D-models accounting for the height as well. However, since </del>the <del class="diffchange diffchange-inline">ionosphere is a manifestation </del>of <del class="diffchange diffchange-inline">space weather</del>, <del class="diffchange diffchange-inline">geodesy should contribute to space weather research</del>, and <del class="diffchange diffchange-inline">in this respect completely new scientific questions arise</del>, <del class="diffchange diffchange-inline">in particular with respect </del>to the <del class="diffchange diffchange-inline">so called “geo-effect”</del>, which <del class="diffchange diffchange-inline">is the impact of space weather in general</del>.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Redistribution of masses induce temporal variations of Earth's gravity field where 1 degree spherical harmonics correspond </ins>to the <ins class="diffchange diffchange-inline">Earth’s centre of mass variations (long term mean of them determines the ITRF origin) </ins>and <ins class="diffchange diffchange-inline">2 degree spherical harmonics correspond </ins>to <ins class="diffchange diffchange-inline">Earth rotation changes</ins>. <ins class="diffchange diffchange-inline"> Satellite altimetry enables observation of changes in geometry of sea level </ins>and <ins class="diffchange diffchange-inline">space geodesy techniques enable </ins>observations <ins class="diffchange diffchange-inline">of changes in geometry of </ins>the <ins class="diffchange diffchange-inline">Earth's crust by monitoring horizontal and vertical deformations of site positions</ins>. <ins class="diffchange diffchange-inline"> Sea surface height varies due to thermal expansion </ins>of <ins class="diffchange diffchange-inline">sea water and changes in ocean water mass arising from melting polar ice cap, mountain glacier ice</ins>, <ins class="diffchange diffchange-inline">as well as due to groundwater storage</ins>. <ins class="diffchange diffchange-inline">The site positions </ins>which <ins class="diffchange diffchange-inline">are determined together with satellite orbit parameters (in </ins>the <ins class="diffchange diffchange-inline">case </ins>of <ins class="diffchange diffchange-inline">SLR</ins>, <ins class="diffchange diffchange-inline">GNSS </ins>and <ins class="diffchange diffchange-inline">DORIS) </ins>or <ins class="diffchange diffchange-inline">radio source coordinates (in </ins>the <ins class="diffchange diffchange-inline">case </ins>of <ins class="diffchange diffchange-inline">VLBI) and Earth orientation parameters (x</ins>, <ins class="diffchange diffchange-inline">y pole coordinates</ins>, <ins class="diffchange diffchange-inline">UT1-UTC/LOD </ins>and <ins class="diffchange diffchange-inline">precession-nutation corrections dX</ins>, <ins class="diffchange diffchange-inline">dY) are then used </ins>to <ins class="diffchange diffchange-inline">build </ins>the <ins class="diffchange diffchange-inline">global ITRF which changes due to e.g. plate tectonics, postglacial rebound, atmospheric</ins>, <ins class="diffchange diffchange-inline">hydrology and ocean loading and earthquakes. In these three components of geodesy </ins>which <ins class="diffchange diffchange-inline">should be integrated into one unique physical and mathematical model there are changes that are described by spatial and temporal geodetic time series</ins>.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">There are two principal goals </del>of the <del class="diffchange diffchange-inline">proposed study group</del>. <del class="diffchange diffchange-inline">First</del>, to <del class="diffchange diffchange-inline">connect </del>the <del class="diffchange diffchange-inline">“geodetic” ionosphere research </del>with <del class="diffchange diffchange-inline">solar</del>-<del class="diffchange diffchange-inline">terrestrial physics, </del>in order to <del class="diffchange diffchange-inline">consider </del>the <del class="diffchange diffchange-inline">complete cause</del>-<del class="diffchange diffchange-inline">effect</del>-<del class="diffchange diffchange-inline">chain</del>. <del class="diffchange diffchange-inline">Second</del>, <del class="diffchange diffchange-inline">the above mentioned “geo</del>-<del class="diffchange diffchange-inline">effect” has to </del>be <del class="diffchange diffchange-inline">investigated in detail, which is </del>an important <del class="diffchange diffchange-inline">aspect, because modern society depends </del>to a <del class="diffchange diffchange-inline">great extent on technology</del>, <del class="diffchange diffchange-inline">i</del>.<del class="diffchange diffchange-inline">e. technology </del>that can be <del class="diffchange diffchange-inline">disturbed</del>, <del class="diffchange diffchange-inline">that can be harmed or that even can be destroyed by extreme space weather events</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Different time series analysis methods have been applied to analyze all elements </ins>of the <ins class="diffchange diffchange-inline">Earth’s system for better understanding the mutual relationship between them</ins>. <ins class="diffchange diffchange-inline">The nature of considered signals in the geodetic time series is mostly wideband</ins>, <ins class="diffchange diffchange-inline">irregular and non-stationary. Thus, it is recommended </ins>to <ins class="diffchange diffchange-inline">apply spectra-temporal analyzes methods to analyze and compare these series to explain </ins>the <ins class="diffchange diffchange-inline">mutual interaction between them in different time and different frequency bands. The main problems to deal </ins>with <ins class="diffchange diffchange-inline">is to estimate the deterministic (including trend and periodic variations) and stochastic (non-periodic variations and random changes described by different noise characters) components in these geodetic time series as well as to apply the appropriate methods of spectra</ins>-<ins class="diffchange diffchange-inline">temporal comparison of these series.  </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">The multiple methods of time series analysis may be encouraged to be applied to the preprocessing of raw data from various geodetic measurements </ins>in order to <ins class="diffchange diffchange-inline">promote the quality level of enhancement of signals existing in these data. The topic on the improvement of the edge effects in time series analysis should be also considered, since they may affect </ins>the <ins class="diffchange diffchange-inline">reliability of long</ins>-<ins class="diffchange diffchange-inline">range tendency (trends) estimated from data series as well as the real</ins>-<ins class="diffchange diffchange-inline">time data processing and prediction</ins>. <ins class="diffchange diffchange-inline">For coping with small geodetic samples one can apply simulation-based methods and if the data are sparse</ins>, <ins class="diffchange diffchange-inline">Monte</ins>-<ins class="diffchange diffchange-inline">Carlo simulation or bootstrap technique may </ins>be <ins class="diffchange diffchange-inline">useful. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Measurements by space geodetic techniques provide </ins>an important <ins class="diffchange diffchange-inline">contribution </ins>to <ins class="diffchange diffchange-inline">the understanding of climate change. The analysis of Earth rotation and geophysical time series as well as global sea level variations shows that there is </ins>a <ins class="diffchange diffchange-inline">mutual relationship between them for oscillations with periods from a few days to decades. The thermal annual cycle caused by the Earth's orbital motion modified by variable solar activity induces seasonal variations the Earth’s fluid layers, thus in the Earth rotation</ins>, <ins class="diffchange diffchange-inline">sea level variations as well as in the changes of the Earth's gravity field and centre of mass</ins>. <ins class="diffchange diffchange-inline">The interrelationships between the geodetic time series and changes of global troposphere temperature show </ins>that <ins class="diffchange diffchange-inline">they provide very important information about the Earth's climate change (for example global sea level increases faster during El Nino events associated with the increase of global temperature and in this time the increase of length of day </ins>can be <ins class="diffchange diffchange-inline">also noticed).  Thus</ins>, <ins class="diffchange diffchange-inline">the spectra-temporal analysis and comparison of geodetic time series should also include time series associated with solar activity.    </ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Objectives===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Objectives===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">improvements </del>and <del class="diffchange diffchange-inline">enlargements </del>of <del class="diffchange diffchange-inline">ionosphere models (</del>including <del class="diffchange diffchange-inline">scintillations)</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Study of the nature of geodetic time series to choose optimum time series analysis methods for filtering, spectral analysis, time frequency analysis and prediction.</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">geodetic contributions to investigate </del>the <del class="diffchange diffchange-inline">impact </del>of <del class="diffchange diffchange-inline">space weather/</del>the <del class="diffchange diffchange-inline">ionosphere (extreme events) on satellite motion</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* Study of Earth's geometry, rotation </ins>and <ins class="diffchange diffchange-inline">gravity field variations and their geophysical causes in different frequency bands.</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* geodetic <del class="diffchange diffchange-inline">contributions </del>to <del class="diffchange diffchange-inline">investigate </del>the <del class="diffchange diffchange-inline">impact </del>of <del class="diffchange diffchange-inline">space weather/the ionosphere (extreme events) on communication </del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* Evaluation of appropriate covariance matrices for the time series by applying the law </ins>of <ins class="diffchange diffchange-inline">error propagation to the original measurements, </ins>including <ins class="diffchange diffchange-inline">weighting schemes, regularization, etc.</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">investigations </del>of <del class="diffchange diffchange-inline">the impact </del>of <del class="diffchange diffchange-inline">space weather/the ionosphere (extreme events) on remote sensing products </del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Determination of </ins>the <ins class="diffchange diffchange-inline">statistical significance levels </ins>of the <ins class="diffchange diffchange-inline">results obtained by different time series analysis methods and algorithms applied to geodetic time series.</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">investigations </del>of <del class="diffchange diffchange-inline">the impact of space weather/the </del>ionosphere <del class="diffchange diffchange-inline">(extreme events) on terrestrial technical infrastructure (metallic networks, power grids)</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* Comparison of different time series analysis methods in order to point out their advantages and disadvantages.</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">“geodetic observations” </del>of <del class="diffchange diffchange-inline">currents (ring current, electrojets)</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Application and development of time frequency analysis methods to detect the relationship between </ins>geodetic <ins class="diffchange diffchange-inline">time series and time series associated with the solar activity in order </ins>to <ins class="diffchange diffchange-inline">solve </ins>the <ins class="diffchange diffchange-inline">problems related to the climate change. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* Recommendations </ins>of <ins class="diffchange diffchange-inline">different time series analysis methods for solving problems concerning specific geodetic time series.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Detection </ins>of <ins class="diffchange diffchange-inline">reliable station velocities and their uncertainties with taking into account their non-linear motion and environmental loadings and identification </ins>of <ins class="diffchange diffchange-inline">site clusters with similar velocities </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Deterministic and stochastic modelling and prediction </ins>of <ins class="diffchange diffchange-inline">troposphere and </ins>ionosphere <ins class="diffchange diffchange-inline">parameters for real time precise GNSS positioning. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Better Earth Orientation Parameters short-term prediction using the extrapolation models </ins>of <ins class="diffchange diffchange-inline">the fluid excitation functions.  </ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Program of activities===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Program of activities===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* the <del class="diffchange diffchange-inline">maintaining </del>of <del class="diffchange diffchange-inline">a website </del>for <del class="diffchange diffchange-inline">general information as well as for internal exchange </del>of data <del class="diffchange diffchange-inline">sets </del>and <del class="diffchange diffchange-inline">results</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">Organization of a session on time series analysis in geodesy at </ins>the <ins class="diffchange diffchange-inline">Hotine-Marussi Symposium in 2022.</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">* organization of a workshop w.r.t</del>. <del class="diffchange diffchange-inline">space weather and geo-effects</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* Co-organization </ins>of <ins class="diffchange diffchange-inline">the PICO sessions "Mathematical methods </ins>for <ins class="diffchange diffchange-inline">the analysis </ins>of <ins class="diffchange diffchange-inline">potential field </ins>data and <ins class="diffchange diffchange-inline">geodetic time series" at the European Geosciences Union General Assemblies in Vienna, Austria</ins>.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">* publication of important findings</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Membership===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Membership===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'' '''<del class="diffchange diffchange-inline">Klaus Börger </del>(<del class="diffchange diffchange-inline">Germany</del>), chair''' <br /> Mahmut <del class="diffchange diffchange-inline">Onur Karsioglu </del>(Turkey)<del class="diffchange diffchange-inline">, vice-chair </del><br /> <del class="diffchange diffchange-inline">Michael Schmidt </del>(Germany) <br /> <del class="diffchange diffchange-inline">Jürgen Matzka </del>(Germany) <br /> <del class="diffchange diffchange-inline">Barbara Görres </del>(<del class="diffchange diffchange-inline">Germany</del>) <br /> <del class="diffchange diffchange-inline">George Zhizhao Liu </del>(<del class="diffchange diffchange-inline">Hong Kong, China</del>) <br /> <del class="diffchange diffchange-inline">Ehsan Forootan </del>(<del class="diffchange diffchange-inline">Germany</del>) <br /> <del class="diffchange diffchange-inline">Johannes Hinrichs </del>(<del class="diffchange diffchange-inline">Germany</del>) <br />''</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'' '''<ins class="diffchange diffchange-inline">Wieslaw Kosek </ins>(<ins class="diffchange diffchange-inline">Poland</ins>), chair ''' <ins class="diffchange diffchange-inline"><br /> Orhan Akyilmaz (Turkey) <br /> Johannes Boehm (Austria) <br /> Xavier Collilieux (France) <br /> Olivier de Viron (France) <br /> Laura Fernandez (Argentina) <br /> Richard Gross (USA) </ins><br /> Mahmut <ins class="diffchange diffchange-inline">O. Karslioglu </ins>(Turkey) <br /> <ins class="diffchange diffchange-inline">Anna Kłos (Poland) <br /> Hans Neuner </ins>(Germany) <br /> <ins class="diffchange diffchange-inline">Tomasz Niedzielski (Poland) <br /> Sergei Petrov (Russia) <br /> Waldemar Popiński (Poland) <br /> Michael Schmidt </ins>(Germany) <br /> <ins class="diffchange diffchange-inline">Michel Van Camp </ins>(<ins class="diffchange diffchange-inline">Belgium</ins>) <br />  </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Jan Vondrák </ins>(<ins class="diffchange diffchange-inline">Czech Republic</ins>) <br /> <ins class="diffchange diffchange-inline">Dawei Zheng </ins>(<ins class="diffchange diffchange-inline">China</ins>) <br /> <ins class="diffchange diffchange-inline">Yonghong Zhou </ins>(<ins class="diffchange diffchange-inline">China</ins>) <br />''</div></td></tr>
</table>
Novak
http://icct.kma.zcu.cz/index.php?title=JSG_T.33&diff=598&oldid=prev
Novak at 10:34, 10 June 2020
2020-06-10T10:34:48Z
<p></p>
<table class="diff diff-contentalign-left" data-mw="interface">
<col class="diff-marker" />
<col class="diff-content" />
<col class="diff-marker" />
<col class="diff-content" />
<tr style="vertical-align: top;" lang="en">
<td colspan="2" style="background-color: white; color:black; text-align: center;">← Older revision</td>
<td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 10:34, 10 June 2020</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1" >Line 1:</td>
<td colspan="2" class="diff-lineno">Line 1:</td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><big>'''JSG T.33: <del class="diffchange diffchange-inline">Space weather </del>and <del class="diffchange diffchange-inline">ionosphere</del>'''</big></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><big>'''JSG T.33: <ins class="diffchange diffchange-inline">Time series in geodesy </ins>and <ins class="diffchange diffchange-inline">geodynamics</ins>'''</big></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Chair: '': <del class="diffchange diffchange-inline">Klaus Börger </del>(<del class="diffchange diffchange-inline">Germany</del>)''<br></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Chair: '': <ins class="diffchange diffchange-inline">Wieslaw Kosek </ins>(<ins class="diffchange diffchange-inline">Poland</ins>)''<br></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Affiliation:''Commissions 1, 4 <del class="diffchange diffchange-inline">and </del>GGOS''</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Affiliation:''Commissions 1, <ins class="diffchange diffchange-inline">3 and </ins>4<ins class="diffchange diffchange-inline">, </ins>GGOS''</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>__TOC__</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>__TOC__</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>===<del class="diffchange diffchange-inline">Terms of Reference</del>===</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>===<ins class="diffchange diffchange-inline">Introduction</ins>===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>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.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>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.</div></td></tr>
</table>
Novak
http://icct.kma.zcu.cz/index.php?title=JSG_T.33&diff=537&oldid=prev
Pendl: Pendl moved page JSG0.20 to JSG T.33
2020-06-01T09:17:34Z
<p>Pendl moved page <a href="/index.php?title=JSG0.20" class="mw-redirect" title="JSG0.20">JSG0.20</a> to <a href="/index.php?title=JSG_T.33" title="JSG T.33">JSG T.33</a></p>
<table class="diff diff-contentalign-left" data-mw="interface">
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<td colspan="1" style="background-color: white; color:black; text-align: center;">← Older revision</td>
<td colspan="1" style="background-color: white; color:black; text-align: center;">Revision as of 09:17, 1 June 2020</td>
</tr><tr><td colspan="2" style="text-align: center;" lang="en"><div class="mw-diff-empty">(No difference)</div>
</td></tr></table>
Pendl
http://icct.kma.zcu.cz/index.php?title=JSG_T.33&diff=536&oldid=prev
Pendl at 09:17, 1 June 2020
2020-06-01T09:17:27Z
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<td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 09:17, 1 June 2020</td>
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<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><big>'''JSG <del class="diffchange diffchange-inline">0</del>.<del class="diffchange diffchange-inline">20</del>: Space weather and ionosphere'''</big></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><big>'''JSG <ins class="diffchange diffchange-inline">T</ins>.<ins class="diffchange diffchange-inline">33</ins>: Space weather and ionosphere'''</big></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Chair: '': Klaus Börger (Germany)''<br></div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>Chair: '': Klaus Börger (Germany)''<br></div></td></tr>
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Pendl
http://icct.kma.zcu.cz/index.php?title=JSG_T.33&diff=414&oldid=prev
Admin at 08:15, 29 April 2016
2016-04-29T08:15:30Z
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<td colspan="2" style="background-color: white; color:black; text-align: center;">Revision as of 08:15, 29 April 2016</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l1" >Line 1:</td>
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<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><big>'''JSG 0.20: <del class="diffchange diffchange-inline">High resolution harmonic analysis </del>and <del class="diffchange diffchange-inline">synthesis of potential fields</del>'''</big></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><big>'''JSG 0.20: <ins class="diffchange diffchange-inline">Space weather </ins>and <ins class="diffchange diffchange-inline">ionosphere</ins>'''</big></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Chair: ''<del class="diffchange diffchange-inline">Sten Claessens </del>(<del class="diffchange diffchange-inline">Australia</del>)''<br></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Chair: ''<ins class="diffchange diffchange-inline">: Klaus Börger </ins>(<ins class="diffchange diffchange-inline">Germany</ins>)''<br></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Affiliation:''<del class="diffchange diffchange-inline">Comm. 2 </del>and GGOS''</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Affiliation:''<ins class="diffchange diffchange-inline">Commissions 1, 4 </ins>and GGOS''</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>__TOC__</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>__TOC__</div></td></tr>
<tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l8" >Line 8:</td>
<td colspan="2" class="diff-lineno">Line 8:</td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Terms of Reference===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Terms of Reference===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">The gravitational fields </del>of <del class="diffchange diffchange-inline">the Earth </del>and <del class="diffchange diffchange-inline">other celestial bodies in </del>the <del class="diffchange diffchange-inline">Solar System are customarily represented by a series of spherical harmonic coefficients. The models made up </del>of these <del class="diffchange diffchange-inline">harmonic coefficients are used widely in a large range of applications within </del>geodesy. In <del class="diffchange diffchange-inline">addition, spherical harmonics are now used </del>in <del class="diffchange diffchange-inline">many other areas of science such as geomagnetism, particle physics</del>, <del class="diffchange diffchange-inline">planetary geophysics, biochemistry and computer graphics, but one of the first applications of spherical harmonics was related </del>to <del class="diffchange diffchange-inline">the gravitational potential, </del>and <del class="diffchange diffchange-inline">geodesists are still at the forefront of research into spherical harmonics. This holds true especially when it comes </del>to the <del class="diffchange diffchange-inline">extension of spherical harmonic series to ever higher degree and order (d/o)</del>.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">It is well known that space geodetic methods are under influence </ins>of <ins class="diffchange diffchange-inline">ionospheric refraction, </ins>and <ins class="diffchange diffchange-inline">therefore from </ins>the <ins class="diffchange diffchange-inline">very beginning </ins>of these <ins class="diffchange diffchange-inline">techniques </ins>geodesy <ins class="diffchange diffchange-inline">deals with the ionosphere</ins>. In <ins class="diffchange diffchange-inline">this context sophisticated methods and models have been developed </ins>in <ins class="diffchange diffchange-inline">order to determine</ins>, to <ins class="diffchange diffchange-inline">represent </ins>and to <ins class="diffchange diffchange-inline">predict </ins>the <ins class="diffchange diffchange-inline">ionosphere</ins>. <ins class="diffchange diffchange-inline">Apart from this </ins>the <ins class="diffchange diffchange-inline">ionosphere fits into another issue called „space weather“, which describes </ins>the <ins class="diffchange diffchange-inline">interactions between </ins>the <ins class="diffchange diffchange-inline">constituents </ins>of <ins class="diffchange diffchange-inline">space and earth</ins>. <ins class="diffchange diffchange-inline">To be more precise space weather means </ins>the <ins class="diffchange diffchange-inline">conditions in space </ins>with <ins class="diffchange diffchange-inline">a significant impact on space</ins>-<ins class="diffchange diffchange-inline">based and ground</ins>-<ins class="diffchange diffchange-inline">based technology as well as on earth and its inhabitants</ins>. <ins class="diffchange diffchange-inline"> Solar radiation</ins>, <ins class="diffchange diffchange-inline">that </ins>is <ins class="diffchange diffchange-inline">electromagnetic emission as well as particle emission</ins>, <ins class="diffchange diffchange-inline">is </ins>the <ins class="diffchange diffchange-inline">main cause or “drive” </ins>of <ins class="diffchange diffchange-inline">space weather</ins>.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">The maximum d/o of spherical harmonic series of </del>the <del class="diffchange diffchange-inline">Earth’s gravitational potential has risen steadily over </del>the <del class="diffchange diffchange-inline">past decades. The highest d/o models currently listed by </del>the <del class="diffchange diffchange-inline">International Centre for Global Earth Models (ICGEM) have a maximum d/o </del>of <del class="diffchange diffchange-inline">2190</del>. <del class="diffchange diffchange-inline">In recent years, spherical harmonic models of </del>the <del class="diffchange diffchange-inline">topography and topographic potential to d/o 10,800 have been computed, and </del>with <del class="diffchange diffchange-inline">ever</del>-<del class="diffchange diffchange-inline">increasing computational prowess, expansions to even higher d/o are feasible. For comparison, the current highest</del>-<del class="diffchange diffchange-inline">resolution global gravity model has a resolution of 7</del>.<del class="diffchange diffchange-inline">2” in the space domain</del>, <del class="diffchange diffchange-inline">which </del>is <del class="diffchange diffchange-inline">roughly equivalent to d/o 90</del>,<del class="diffchange diffchange-inline">000 in </del>the <del class="diffchange diffchange-inline">frequency domain, while the highest-resolution global Digital Elevation Model has a resolution </del>of <del class="diffchange diffchange-inline">5 m, equivalent to d/o ~4,000,000</del>.</div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">The increasing maximum d/o of harmonic models </del>has <del class="diffchange diffchange-inline">posed and continues </del>to <del class="diffchange diffchange-inline">pose both theoretical </del>and <del class="diffchange diffchange-inline">practical challenges for </del>the geodetic <del class="diffchange diffchange-inline">community</del>. <del class="diffchange diffchange-inline">For example</del>, the <del class="diffchange diffchange-inline">computation </del>of <del class="diffchange diffchange-inline">associated Legendre functions of the first kind</del>, <del class="diffchange diffchange-inline">which are required </del>for <del class="diffchange diffchange-inline">spherical harmonic analysis and synthesis</del>, is <del class="diffchange diffchange-inline">traditionally subject </del>to <del class="diffchange diffchange-inline">numerical instabilities </del>and <del class="diffchange diffchange-inline">underflow/overflow problems. Much progress has been made on </del>this <del class="diffchange diffchange-inline">issue by selection of suitable recurrence relations</del>, <del class="diffchange diffchange-inline">summation strategies</del>, <del class="diffchange diffchange-inline">and use </del>of <del class="diffchange diffchange-inline">extended range arithmetic, but further improvements to efficiency may still be achieved</del>.  </div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Originally, geodesy, or to be more precise, space geodetic methods have considered the ionosphere as a disturbing factor that affects signal propagation and that </ins>has to <ins class="diffchange diffchange-inline">be corrected. This (geodetic) perspective has been changed over time </ins>and the <ins class="diffchange diffchange-inline">ionosphere has become a target value so that </ins>geodetic <ins class="diffchange diffchange-inline">observations are used to determine the ionosphere</ins>. <ins class="diffchange diffchange-inline">Different groups have developed models of high quality</ins>, <ins class="diffchange diffchange-inline">e.g. 3D-models which describe </ins>the <ins class="diffchange diffchange-inline">ionosphere as a function </ins>of <ins class="diffchange diffchange-inline">longitude</ins>, <ins class="diffchange diffchange-inline">latitude and time or even 4D-models accounting </ins>for <ins class="diffchange diffchange-inline">the height as well. However</ins>, <ins class="diffchange diffchange-inline">since the ionosphere </ins>is <ins class="diffchange diffchange-inline">a manifestation of space weather, geodesy should contribute </ins>to <ins class="diffchange diffchange-inline">space weather research, </ins>and <ins class="diffchange diffchange-inline">in </ins>this <ins class="diffchange diffchange-inline">respect completely new scientific questions arise</ins>, <ins class="diffchange diffchange-inline">in particular with respect to the so called “geo-effect”</ins>, <ins class="diffchange diffchange-inline">which is the impact </ins>of <ins class="diffchange diffchange-inline">space weather in general</ins>.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>There are <del class="diffchange diffchange-inline">further separate challenges in ultra-high d/o harmonic analysis (</del>the <del class="diffchange diffchange-inline">forward harmonic transform) and synthesis (the inverse harmonic transform)</del>. <del class="diffchange diffchange-inline">Many methods for </del>the <del class="diffchange diffchange-inline">forward harmonic transform exist, typically separated into least</del>-<del class="diffchange diffchange-inline">squares and quadrature methods</del>, <del class="diffchange diffchange-inline">and further comparison between </del>the <del class="diffchange diffchange-inline">two at high d/o</del>, <del class="diffchange diffchange-inline">including studying </del>the <del class="diffchange diffchange-inline">influence of aliasing</del>, is <del class="diffchange diffchange-inline">of interest. The inverse harmonic transform</del>, <del class="diffchange diffchange-inline">including synthesis of </del>a <del class="diffchange diffchange-inline">large variety of quantities</del>, <del class="diffchange diffchange-inline">has received much interest in recent years</del>. <del class="diffchange diffchange-inline">In moving towards higher d/o series</del>, <del class="diffchange diffchange-inline">highly efficient algorithms for synthesis on irregular surfaces and/</del>or <del class="diffchange diffchange-inline">in scattered point locations, are of utmost importance. </del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>There are <ins class="diffchange diffchange-inline">two principal goals of </ins>the <ins class="diffchange diffchange-inline">proposed study group</ins>. <ins class="diffchange diffchange-inline">First, to connect </ins>the <ins class="diffchange diffchange-inline">“geodetic” ionosphere research with solar</ins>-<ins class="diffchange diffchange-inline">terrestrial physics</ins>, <ins class="diffchange diffchange-inline">in order to consider </ins>the <ins class="diffchange diffchange-inline">complete cause-effect-chain. Second</ins>, the <ins class="diffchange diffchange-inline">above mentioned “geo-effect” has to be investigated in detail</ins>, <ins class="diffchange diffchange-inline">which </ins>is <ins class="diffchange diffchange-inline">an important aspect</ins>, <ins class="diffchange diffchange-inline">because modern society depends to </ins>a <ins class="diffchange diffchange-inline">great extent on technology</ins>, <ins class="diffchange diffchange-inline">i.e</ins>. <ins class="diffchange diffchange-inline">technology that can be disturbed</ins>, <ins class="diffchange diffchange-inline">that can be harmed </ins>or that <ins class="diffchange diffchange-inline">even can </ins>be <ins class="diffchange diffchange-inline">destroyed by extreme space weather events</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> </div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">Another question </del>that <del class="diffchange diffchange-inline">has occupied geodesists for many decades is whether there is a substantial benefit to the use of oblate ellipsoidal (or spheroidal) harmonics instead of spherical harmonics.  The limitations of the spherical harmonic series for use on or near the Earth’s surface are becoming more and more apparent as the maximum d/o of the harmonic series increase. There are still open questions about the divergence effect and the amplification of the omission error in spherical and spheroidal harmonic series inside the Brillouin surface. </del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> </div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">The Hotine-Jekeli transformation between spherical and spheroidal harmonic coefficients has proven very useful, in particular for spherical harmonic analysis of data on a reference ellipsoid. It has recently been improved upon and extended, while alternatives using surface spherical harmonics have also been proposed, but the performance of the transformations at very high d/o may </del>be <del class="diffchange diffchange-inline">improved further. Direct use of spheroidal harmonic series requires (ratios of) associated Legendre functions of the second kind, and their stable and efficient computation is also of ongoing interest.</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Objectives===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Objectives===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">The objectives </del>of <del class="diffchange diffchange-inline">this study group are to:</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* improvements and enlargements </ins>of <ins class="diffchange diffchange-inline">ionosphere models (including scintillations)</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Create and compare stable and efficient methods for computation of ultra-high degree and order associated Legendre functions </del>of the <del class="diffchange diffchange-inline">first and second kind </del>(<del class="diffchange diffchange-inline">or ratios thereof</del>)<del class="diffchange diffchange-inline">, plus its derivatives and integrals.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">geodetic contributions to investigate the impact </ins>of <ins class="diffchange diffchange-inline">space weather/</ins>the <ins class="diffchange diffchange-inline">ionosphere </ins>(<ins class="diffchange diffchange-inline">extreme events</ins>) <ins class="diffchange diffchange-inline">on satellite motion</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Study </del>the <del class="diffchange diffchange-inline">divergence effect </del>of <del class="diffchange diffchange-inline">ultra-high degree spherical and spheroidal harmonic series inside </del>the <del class="diffchange diffchange-inline">Brillouin sphere/spheroid.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">geodetic contributions to investigate </ins>the <ins class="diffchange diffchange-inline">impact </ins>of <ins class="diffchange diffchange-inline">space weather/</ins>the <ins class="diffchange diffchange-inline">ionosphere (extreme events) on communication </ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Verify </del>the <del class="diffchange diffchange-inline">numerical performance </del>of <del class="diffchange diffchange-inline">transformations between spherical and spheroidal harmonic coefficients to ultra-high degree and order.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">investigations of </ins>the <ins class="diffchange diffchange-inline">impact </ins>of <ins class="diffchange diffchange-inline">space weather/the ionosphere (extreme events) on remote sensing products </ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Compare least-squares and quadrature approaches to very high-degree and order spherical and spheroidal harmonic analysis.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">investigations of the impact of space weather/the ionosphere (extreme events) on terrestrial technical infrastructure </ins>(<ins class="diffchange diffchange-inline">metallic networks, power grids</ins>)</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">* Study efficient methods for ultra-high degree and order harmonic analysis </del>(<del class="diffchange diffchange-inline">the forward harmonic transform</del>) <del class="diffchange diffchange-inline">for a variety of data types and boundary surfaces.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">“geodetic observations” of currents </ins>(<ins class="diffchange diffchange-inline">ring current, electrojets</ins>)</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Study efficient methods for ultra-high degree and order harmonic synthesis </del>(<del class="diffchange diffchange-inline">the inverse harmonic transform</del>) <del class="diffchange diffchange-inline">of point values and area means of all potential quantities of interest on regular and irregular surfaces.</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Program of activities===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Program of activities===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Providing </del>a <del class="diffchange diffchange-inline">platform </del>for <del class="diffchange diffchange-inline">increased cooperation between group members, facilitating and encouraging </del>exchange of <del class="diffchange diffchange-inline">ideas </del>and <del class="diffchange diffchange-inline">research </del>results<del class="diffchange diffchange-inline">.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">the maintaining of </ins>a <ins class="diffchange diffchange-inline">website </ins>for <ins class="diffchange diffchange-inline">general information as well as for internal </ins>exchange of <ins class="diffchange diffchange-inline">data sets </ins>and results</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Creating and updating </del>a <del class="diffchange diffchange-inline">bibliographic list of relevant publications from both the geodetic community as well as other disciplines for the perusal of group members</del>.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">organization of </ins>a <ins class="diffchange diffchange-inline">workshop w.r.t</ins>. <ins class="diffchange diffchange-inline">space weather and geo-effects</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>* <del class="diffchange diffchange-inline">Organizing working meetings at international symposia and presenting research results in the appropriate sessions.</del></div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>* <ins class="diffchange diffchange-inline">publication of important findings</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Membership===</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>===Membership===</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>'' '''<del class="diffchange diffchange-inline">Sten Claessens </del>(<del class="diffchange diffchange-inline">Australia</del>), chair''' <br /> <del class="diffchange diffchange-inline">Hussein Abd-Elmotaal </del>(<del class="diffchange diffchange-inline">Egypt</del>) <br /> <del class="diffchange diffchange-inline">Oleh Abrykosov </del>(Germany) <br /> <del class="diffchange diffchange-inline">Blažej Bucha (Slovakia) <br /> Toshio Fukushima (Japan) <br /> Thomas Grombein </del>(Germany) <br /> <del class="diffchange diffchange-inline">Christian Gruber </del>(Germany) <br /> <del class="diffchange diffchange-inline">Eliška Hamáčková </del>(<del class="diffchange diffchange-inline">Czech Republic</del>) <br /> <del class="diffchange diffchange-inline">Christian Hirt </del>(Germany) <br /> <del class="diffchange diffchange-inline">Christopher Jekeli (USA) <br /> Otakar Nesvadba (Czech Republic) <br /> Moritz Rexer (Germany) <br /> Josef Sebera (Czech Republic) <br /> Kurt Seitz </del>(Germany) <br />''</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>'' '''<ins class="diffchange diffchange-inline">Klaus Börger </ins>(<ins class="diffchange diffchange-inline">Germany</ins>), chair''' <br /> <ins class="diffchange diffchange-inline">Mahmut Onur Karsioglu </ins>(<ins class="diffchange diffchange-inline">Turkey</ins>)<ins class="diffchange diffchange-inline">, vice-chair </ins><br /> <ins class="diffchange diffchange-inline">Michael Schmidt </ins>(Germany) <br /> <ins class="diffchange diffchange-inline">Jürgen Matzka </ins>(Germany) <br /> <ins class="diffchange diffchange-inline">Barbara Görres </ins>(Germany) <br /> <ins class="diffchange diffchange-inline">George Zhizhao Liu </ins>(<ins class="diffchange diffchange-inline">Hong Kong, China</ins>) <br /> <ins class="diffchange diffchange-inline">Ehsan Forootan </ins>(Germany) <br /> <ins class="diffchange diffchange-inline">Johannes Hinrichs </ins>(Germany) <br />''</div></td></tr>
</table>
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http://icct.kma.zcu.cz/index.php?title=JSG_T.33&diff=413&oldid=prev
Admin: Created page with "<big>'''JSG 0.20: High resolution harmonic analysis and synthesis of potential fields'''</big> Chair: ''Sten Claessens (Australia)''<br> Affiliation:''Comm. 2 and GGOS'' __T..."
2016-04-29T08:03:17Z
<p>Created page with "<big>'''JSG 0.20: High resolution harmonic analysis and synthesis of potential fields'''</big> Chair: ''Sten Claessens (Australia)''<br> Affiliation:''Comm. 2 and GGOS'' __T..."</p>
<p><b>New page</b></p><div><big>'''JSG 0.20: High resolution harmonic analysis and synthesis of potential fields'''</big><br />
<br />
Chair: ''Sten Claessens (Australia)''<br><br />
Affiliation:''Comm. 2 and GGOS''<br />
<br />
__TOC__<br />
<br />
===Terms of Reference===<br />
<br />
The gravitational fields of the Earth and other celestial bodies in the Solar System are customarily represented by a series of spherical harmonic coefficients. The models made up of these harmonic coefficients are used widely in a large range of applications within geodesy. In addition, spherical harmonics are now used in many other areas of science such as geomagnetism, particle physics, planetary geophysics, biochemistry and computer graphics, but one of the first applications of spherical harmonics was related to the gravitational potential, and geodesists are still at the forefront of research into spherical harmonics. This holds true especially when it comes to the extension of spherical harmonic series to ever higher degree and order (d/o).<br />
The maximum d/o of spherical harmonic series of the Earth’s gravitational potential has risen steadily over the past decades. The highest d/o models currently listed by the International Centre for Global Earth Models (ICGEM) have a maximum d/o of 2190. In recent years, spherical harmonic models of the topography and topographic potential to d/o 10,800 have been computed, and with ever-increasing computational prowess, expansions to even higher d/o are feasible. For comparison, the current highest-resolution global gravity model has a resolution of 7.2” in the space domain, which is roughly equivalent to d/o 90,000 in the frequency domain, while the highest-resolution global Digital Elevation Model has a resolution of 5 m, equivalent to d/o ~4,000,000.<br />
<br />
The increasing maximum d/o of harmonic models has posed and continues to pose both theoretical and practical challenges for the geodetic community. For example, the computation of associated Legendre functions of the first kind, which are required for spherical harmonic analysis and synthesis, is traditionally subject to numerical instabilities and underflow/overflow problems. Much progress has been made on this issue by selection of suitable recurrence relations, summation strategies, and use of extended range arithmetic, but further improvements to efficiency may still be achieved. <br />
<br />
There are further separate challenges in ultra-high d/o harmonic analysis (the forward harmonic transform) and synthesis (the inverse harmonic transform). Many methods for the forward harmonic transform exist, typically separated into least-squares and quadrature methods, and further comparison between the two at high d/o, including studying the influence of aliasing, is of interest. The inverse harmonic transform, including synthesis of a large variety of quantities, has received much interest in recent years. In moving towards higher d/o series, highly efficient algorithms for synthesis on irregular surfaces and/or in scattered point locations, are of utmost importance. <br />
<br />
Another question that has occupied geodesists for many decades is whether there is a substantial benefit to the use of oblate ellipsoidal (or spheroidal) harmonics instead of spherical harmonics. The limitations of the spherical harmonic series for use on or near the Earth’s surface are becoming more and more apparent as the maximum d/o of the harmonic series increase. There are still open questions about the divergence effect and the amplification of the omission error in spherical and spheroidal harmonic series inside the Brillouin surface. <br />
<br />
The Hotine-Jekeli transformation between spherical and spheroidal harmonic coefficients has proven very useful, in particular for spherical harmonic analysis of data on a reference ellipsoid. It has recently been improved upon and extended, while alternatives using surface spherical harmonics have also been proposed, but the performance of the transformations at very high d/o may be improved further. Direct use of spheroidal harmonic series requires (ratios of) associated Legendre functions of the second kind, and their stable and efficient computation is also of ongoing interest.<br />
<br />
===Objectives===<br />
<br />
The objectives of this study group are to:<br />
* Create and compare stable and efficient methods for computation of ultra-high degree and order associated Legendre functions of the first and second kind (or ratios thereof), plus its derivatives and integrals.<br />
* Study the divergence effect of ultra-high degree spherical and spheroidal harmonic series inside the Brillouin sphere/spheroid.<br />
* Verify the numerical performance of transformations between spherical and spheroidal harmonic coefficients to ultra-high degree and order.<br />
* Compare least-squares and quadrature approaches to very high-degree and order spherical and spheroidal harmonic analysis.<br />
* Study efficient methods for ultra-high degree and order harmonic analysis (the forward harmonic transform) for a variety of data types and boundary surfaces.<br />
* Study efficient methods for ultra-high degree and order harmonic synthesis (the inverse harmonic transform) of point values and area means of all potential quantities of interest on regular and irregular surfaces.<br />
<br />
===Program of activities===<br />
<br />
* Providing a platform for increased cooperation between group members, facilitating and encouraging exchange of ideas and research results.<br />
* Creating and updating a bibliographic list of relevant publications from both the geodetic community as well as other disciplines for the perusal of group members.<br />
* Organizing working meetings at international symposia and presenting research results in the appropriate sessions.<br />
<br />
===Membership===<br />
<br />
'' '''Sten Claessens (Australia), chair''' <br /> Hussein Abd-Elmotaal (Egypt) <br /> Oleh Abrykosov (Germany) <br /> Blažej Bucha (Slovakia) <br /> Toshio Fukushima (Japan) <br /> Thomas Grombein (Germany) <br /> Christian Gruber (Germany) <br /> Eliška Hamáčková (Czech Republic) <br /> Christian Hirt (Germany) <br /> Christopher Jekeli (USA) <br /> Otakar Nesvadba (Czech Republic) <br /> Moritz Rexer (Germany) <br /> Josef Sebera (Czech Republic) <br /> Kurt Seitz (Germany) <br />''</div>
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