Journal of Geodesy (2003) 76: 715–718 DOI 10.1007/s00190-003-0316-7

IAG Newsletter Ole Baltazar Andersen IAG Central Bureau, Department of Geophysics, Juliane Maries vej 30, DK-2100 Copenhagen Ø, Denmark e-mail: [email protected]; Fax: +45 3536 5357; URL:http://www.gfy.ku.dk/iag/

The IAG Newsletter is under the editorial responsibility of the IAG Central Bureau. It is an open forum and contributors are welcome to send material (preferably in electronic form) to the IAG Central Bureau. These contributions should complement information sent by IAG officials or by IAG symposia organizers (reports and announcements). Each IAG Newsletter includes several of the following topics: I. general information II. reports of IAG symposia III. reports by commissions, special commissions or study groups IV. symposia announcements V. book reviews VI. fast bibliography

Announcement IAG Young Authors Award, 2001 The executive committe of the IAG has decided to award Susan Skone the IAG Young Authors Award, 2001 for your paper ‘‘The inpact of magnetic storms on GPS receiver performance’’, published in Journal of Geodesy, Vol. 75, no. 9–10, 2001. The award consist of USD 1000 and an IAG award certificate.

Books for review are the responsibility of: Christian Tiberius TU Delft, Faculty of CEG, Dept. of Mathematical geodesy and positioning P.O.Box 5030 – NL 2600 GA Delft – The Netherlands Fax: (+31) 15 27 83 711 E-mail: [email protected]

Dr. Susan Skone holds B.Sc. degrees in math and physics (1989, 1991) and an M.Sc. in physics (1994) from the University of Alberta. In 1998 she graduated with a Ph.D. in Geomatics Engineering from the University of Calgary (Killam scholar, Amelia Earhart fellow). She has been employed as an Assistant Professor in the Geomatics Department at University of Calgary since January 1999, and is the recipient of a University Faculty Award from the Natural Sciences and Engineering Research Council of Canada (1999–2004). Since 1995 her research has focused on satellite-based global navigation satellite systems. She is actively involved in atmospheric research for GPS applications, and has developed commercial software for ionosphere modelling. Her technical papers have been recognized with numerous international awards, and she has received the Canadian Hunter Young Innovator Award (1999-2000) and the Canadian Aeronautics and Space Institute’s Casey Baldwin Award (2000). She is actively involved with the IAG SSG 1.180: GPS as an Atmospheric Remote Sensing Tool.

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Meeting Announcement IUGG 2003. Sapporo Japan Homepage at: http://www.jamstec.go.jp/jamstec-e/iugg/ index.html Abstract Submission deadline: January 20th, 2003. The International Celestial Reference System – Maintenance and Future Realizations Joint Discussion 16 at IAU General Assembly, 22 July 2003, Darling Harbour Convention Center, Sydney, Australia Homepage at http://www.astronomy2003.com Digital Earth 2003 – International Conference Brno, Czech Republic, Sept. 21–25, 2003 Homepage at http://digitalearth03.geogr.muni.cz/ 15th International Symposium on Earth Tides, Ottawa, Canada, 2–6 August 2004. More info from Shuzo Takemoto [email protected]

Meeting report Minutes of the SIRGAS (Sistema de Referencia Geocentrico para Las Americas) committee meeting, held on october 21 and 22, 2002 Santiago, Chile The president of the Committee highlighted the financial support given by the International Association of Geodesy (IAG), decisive for holding the meeting. The Pan-American Institute of Geography and History (PAIGH), which had approved funds for the project in 2002, could not honor this commitment due to financial difficulties that it is currently facing. Therefore IAG responded to our last minute request, enabling the attendance of eight participants of seven countries of South America, which was decisive for the success of the meeting. All annexes can be found under http://www1.ibge.gov.br/home/geografia/geodesico/ sirgas/principal.htm or http://www.ibge.gov.br/sirgas 1. Status on the integration of the South American countries to SIRGAS (R. Barriga, President of the WG II) (Annex I) 2. Presentation of the SIRGAS 2000 GPS campaign results by the processing centers 2.1 IBGE (S. Costa) (Annex II) 2.2 DGFI (K. Kanniuth) The coordinates obtained in the individual solutions of each processing center (DGFI with Bernese, DGFI with GIPSY and IBGE with Bernese) shown

a consistency between each other of about 5 mm in the horizontal components and 7.5 mm in the vertical component. Resolution: The SIRGAS Committee decided that the final solution of the SIRGAS 2000 GPS campaign will be generated by the combination of three solutions: DGFIs, using the Bernese software; DGFIs, using the GIPSY software; and IBGEs, using the Bernese software. 3. Combination of the processing centers results (H. Drewes/K. Kanniuth/S. Costa) 3.1 Combination strategy and connection to ITRF2000 M. Kumar, from NIMA, presented the following issue: the ITRF solutions are generated using the tide-free system, which is not realistic and contradicts the IAG Resolution 16 of 1983 (Annex III) Resolution: To keep using the tide-free system in the SIRGAS 2000 results and to formally suggest to IAG to manage with the International Earth Rotation Service (IERS) the solution of this issue. 3.2 Determination of velocities According to H. Drewes, it is not enough to consider the results of the SIRGAS 1995 and 2000 campaigns for the determination of the SIRGAS stations velocities. Resolution: The SIRGAS Committee approves H. Drewes proposal of considering the observations of permanent GPS stations and of geodynamic campaigns, in addition to the results of the SIRGAS 1995 and 2000 campaigns, for the determination of the velocity field of the South American continent. 3.3 Final results (coordinates and velocities) Resolution: The SIRGAS Committee accepts in advance as official the final combined results of the SIRGAS 2000 GPS campaign, to be generated by the processing centers in near future. Resolution: The SIRGAS Committee defines the date of December 20, 2002, as the deadline for the processing centers to release the final combined results of the SIRGAS 2000 GPS campaign. Resolution: The SIRGAS Committee defines the date of March 28, 2003, as the deadline for DGFI to release the results of the velocity field for the South American continent. Resolution: The procedures to generate the official results of the SIRGAS 2000 GPS campaign will be described in a final report, similarly to that released during the IAG Scientific Assembly, held in Rio de Janeiro, in 1997. Resolution: The SIRGAS Committee proposes to include in the SIRGAS 2000 GPS campaign final report a special acknowledgment to the processing centers – DGFI and IBGE – by the enormous efforts carried out and by the excellence of the results obtained. 4. Use of the SIRGAS 2000 final results (H. Drewes, Representative of IAG)

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Resolution: The SIRGAS Committee proposes to include in the SIRGAS 2000 GPS campaign final report detailed instructions about how to use the campaign final results. It was recommended that, for countries that have not adopted yet SIRGAS 1995 as reference system, they should adopt the system based on the SIRGAS 2000 results, reference epoch 2000.4. 5. Presentations of the Working Group III ‘‘Vertical Datum’’ (L. Sanchez, President of WG III, and H. Drewes, Representative of IAG) 5.1 Introduction (Annex IV) 5.2 Urgent need of a modern vertical reference system (Annex V) 5.3 Computation of geopotential numbers and physical heights (Annex VI) 5.4 Reference surface: considerations regarding W0 (Annex VII) 5.5 Future activities (Annex VIII), recommending to countries:

7. Closing (L. Fortes) Resolution: The SIRGAS Committee acknowledges the Instituto Geogrfico Militar of Chile for the excellent organization of the meeting and for the support to the Committee members. L. Fortes IBGE Brazil Book Review

• Geodetic leveling of the SIRGAS2000 stations • Connection of leveling networks between neighboring countries • Identification and typing of all leveling lines that connect SIRGAS2000 stations • Typing of the national leveling networks • Identification of the network nodes • UNIFIED determination of the quasi-geoid • Determination of the sea surface topography (SSTop) (GPS positioning of tide gauges) The WG III president offered support to the member countries of the SIRGAS Committee regarding the computation of geopotential numbers and help with parallel tasks. It is emphasized that the height differences to be used in computations are the observed ones, WITHOUT any error distribution or adjustment. 6. Continuation of the discussion on the new statute proposal (L. Fortes and C. Brunini) Resolution: The SIRGAS Committee approves the new project Statute, corresponding to the version originally proposed by the representation of Argentina, with the modifications discussed during the meeting in Santiago del Chile. With the approval of the Statute (Annex IX), the substitute representative of Argentina in the Committee, Claudio Brunini, proposed the names of Luiz Paulo Souto Fortes, from IBGE/Brazil, and Eduardo Andre´s Laura, from IGM/Argentina, respectively for president and vice-president of the project for the next term (2003-2007). The current president of the SIRGAS Committee will contact all countries embraced by the project in order to confirm the names of the representatives in the Committee and, consequently, to define the necessary quorum for electing the new project authorities. This election will be carried out by electronic mail and the elected authorities will be installed in office in July 2003, at the General Assembly of the International Association of Geodesy.

title: author: publisher: ISBN: year: price: pages: size: details:

The Grip of Gravity Prabhakar Gondhalekar Cambridge University Press 0-521-80316-0 2001 GBP 18.95/US$ 28 358 16 · 23.5 cm hardback

This is a modern book on gravity and its implication for space research, astronomy and astrophysics, from Kepler and Galileo to satellite missions dedicated to the exploration of the most subtle questions posed by Einstein’s theory of relativity, from Eo¨tvo¨s’ torsion balance to gravitational lenses in interstellar space. It is a readable book of high scientific level. In the last century, the greatest physicists wrote wonderful books dedicated to their non-specialist colleagues or even to an educated public: Einstein, Eddington, Heisenberg, Schro¨dinger and many more. This has changed: today’s top physicists are frequently

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specialists absorbed by their narrow field of research and by team management, project acquisition etc. Who nowadays finds the time to write a high–level accessible book like Einstein’s ‘The Meaning of Relativity’? Nevertheless, the interest in good general science books persists. ‘The Grip of Gravity’ is such a book. It is accessible to a (highly) educated general public, at the same time providing a wealth of information on the newest research results on gravitation in space sciences to the scientist working in neighboring fields like astronomy or geodesy. The subtitle ‘The quest to understand the laws of motion and gravitation’ indicates that the author is concerned with ‘meaning’ as Einstein was. The scope of the book is excellently indicated by the names forming the titles of the chapters: Aristotle, Kepler, Galileo, Newton, Einstein, Dicke, Hubble & Eddington, Planck. ‘Aristotle’ is the authority on science throughout the Middle Ages, ‘Kepler’ stands for planetary motion, ‘Newton’ represents classical mechanics and ‘Einstein’ outlines the theory of relativity. ‘Dicke’ stands for experimental relativity, which has only become possible by the most precise methods of contemporary satellite techniques. ‘Hubble & Eddington’ discusses astrophysical implications on cosmology, the ‘big bang’, birth, life and death of stars and galaxies, neutron stars, black holes, quasars etc. ‘Planck’ represents the (unresolved) relation between general relativity, quantum theory and the old and new attempts to find a ‘unified theory’ or even a ‘theory of

everything’: supergravitation and superstrings, fantastic and esoteric concepts except for a few initiated specialists. None of them, to my knowledge, has written a book ‘The meaning of supergravitation’, understandable (including the necessary mathematics) as Einstein’s book was. A magnificent building like the present book would have deserved a splendid entrance door welcoming the reader. Unfortunately, I find the first chapter, ‘Aristotle’, slightly disappointing, being an uneven and rather conventional compilation. An exception is the excellent and informative treatment of Arab science. (The very importance of the work ‘Almagest’ would have merited a correct spelling of the Greek original title.) As a general complementary reading I recommend the classic ‘Science and the Modern World’ by Alfred North Whitehead, especially the first chapter, ‘The origins of modern science’. From Kepler on, the book reads like a fascinating science fiction story: much excellent science, precise measurements, elaborate theories, captivating human glimpses. And fiction? The imaginative effort of scientists to explain the measured data by bold, brilliant and fantastic theories surpass everything which a science– fiction author can ever plausibly invent. I strongly recommend this extraordinary book (at least) to every space geodesist. Helmut Moritz Graz Technical University/Austria