Journal of Geodesy (2000) 74: 497±502

IAG Newsletter Ole Baltazar Andersen IAG Central Bureau, Department of Geophysics, Juliane Maries vej 30, DK-2100 Copenhagen é, 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 ocials or by IAG symposia organizers (reports and announcements). Each IAG Newsletter includes several of the following topics:

New Working Group Chairman The IAU/IAG Working Group on ``cartographic coordinates and rotational elements of the planets and satellites'' is continuing under the chairmanship by Dr. Seidelmann. IAG Young Authors Award

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 General Information In Memoriam Professor Dr. Kresimir Colic, Faculty of Geodesy, University of Zagreb, has died. The IAG Central Bureau expresses its deepest sympathy to his family and colleagues. His obituary will be published in a future IAG Newsletter. New IAG Fellow Based on the recommendation from the GALOS president Mr. B.G.Harsson the IAG Executive Committee at its meeting in Nice, April 28 2000 has decided to award Dr. A. Calo Carrera the fellowship of IAG in appreciation of his work for GALOS and Geodesy. 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]

The IAG Executive Committee at its meeting in Nice, 28 April 2000 have decided to award give Peiliang Xu the IAG young authors award. The award is for the paper ``Biases and the accuracy of, and an alternative to, discrete nonlinear ®lters'', Published in JoG, Vol. 73, pp. 35±46, 1999. Peiliang Xu received the B.Eng in surveying engineering in 1983 and the Ph.D in geodesy in 1989, both from Wuhan Technical University of Surveying and Mapping. After being conferred the ®rst Ph.D in geodesy in China, he had been doing research at Delft University of Technology, Stuttgart University, The University of Calgary and National Research Institute for Earth Science and Disaster Prevention in Japan, either as a TUDelft research fellow, an Alexander von Humboldt research fellow, an STA fellow or a research associate. He is currently a Joshu at Disaster Prevention Research Institute, Kyoto University. He has authored or coauthored more than 40 papers in a number of journals such

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as Geophys. J. Int.; J. Geod.; Int. J. Remote Sensing and Commun. Statist. His research interest includes theoretical geodesy, space geodesy, mathematical theory of (geo)inverse ill-posed problems, deformation measuremnt, statistics and global optimization. Meeting reports Minutes of the EC meeting in Nice, 28±29th April, 2000, held in connection with the EGS XXV general assembly. The following were present: F. Sanso President G. Beutler First Vice President. D. Blitzkow Second Vice President C. C. Tscherning Secretary General O. Andersen Ass. Sec. General K. Keller Ass. Sec. General C. Rizos Secretary Sec 1. C. K. Shum President Sec 2. M. Sideris President Sec 3. G. Boedecker Secretary Sec 3. B. Heck President Sec 4. C. Wilson President Sec 5. V. Dehant. Secretary Sec 5. H. Drewes President Comm VIII. C. Boucher President Comm X M. Vermeer. President Comm XIII S. Zerbini President Comm XIV. I. Mueller Past President K. P. Schwarz Past President 1. Approval of agenda F. Sanso presented the agenda containing several additions, and this was approved. 2. Adoption of minutes of Como EC meeting The Minutes of the EC meeting on 28-29th November, 1999, in Como, Italy, had been distributed by e-mail and were published as part of the IAG newsletter in JoG 74/ 02. They were adopted by the EC without corrections. 3. Proposal for an IAG retiree association I. Mueller had distributed a proposal for establishing an association of IAG retiree/seniors/past ocers as a forum to contribute expertise of value to IAG. The association would be open to all IAG fellows and associates, and have meetings at Scienti®c Assemblies and an electronic newsletter. The EC agreed on the general idea of having such an association, and awaits the formal proposal from I. Mueller at the SA in Budapest. 4. IAG Scienti®c Assembly in Budapest 2001 I. Mueller presented the status of the preparation of the Local Organizing Committee (LOC) for the SA in Budapest (3±7 Sept 2001). The preparations are under control and the LOC has established a web page for communication. The Academy of Sciences, where the SA will be held, has 11 meeting rooms of various sizes (max 320 persons). The LOC requests that IAG specify requirements with respect to rooms and sizes at least 3±5 weeks before the SA. Details on the scienti®c program are given under item 8.

5. Feedback on Travaux/Handbook and IAG newsletter O. Andersen informed that the Travaux was distributed on CD and is also available from the Central Bureau (CB) as a book. The Geodesist's Handbook is published, but only a few members of the EC had received it so far. O. Andersen reported that Springer takes up to 2-3 month in printing issues, and also sometimes merges issues which delays publication of the IAG newsletter. This is problematic, and EC stressed that it should be avoided in the future. The IAG Secretary will contact the Editor-in-chief on this issue. Possible distribution of an electronic quarter-annual newsletter via e-mail was considered. 6. Collaboration with ION (Institute of Navigation) The president of ION has approached IAG for coorporation on a GPS book jointly written by authors from IAG and ION. The EC decided to ask F. Sanso to contact R. Neilan, P.Willis, G. Hein or W. Gurtner to establish liaison and to de®ne a fruitful coorporation with ION, based on areas where IAG has strength. 7. Report from the review committee (herinafter RC) G. Beutler presented the report of the IAG review committee (RC) and went through the Executive summary available at ftp://ubecx.unibe.ch/aiub.iag. Only part 5(IAG mission and objectives) and part 6 (IAG structure) were subsequently discussed in detail. Once the comments made below have been given to the RC they have the mandate to create the proposal that should be presented to the EC in March 2001 and subsequent to council at the SA in 2001. IAG mission and objectives A revision of the suggested IAG mission and objectives was carried out, and it was recommended that two more points should be added: a preamble on the usefulness of geodesy for society and another bullet on emerging technologies. IAG structure It was decided by vote that the IAG structure should have commissions, services, and a communication/outreach branch and a few projects represented on the same level. Projects on this top level will be established by the EC. GIGGOS may be one of them, but has not been selected at this point in time. There was agreement on establishing a communication and outreach branch, and that a call for participation should be drafted. It was recommended by the EC that the review committee consider the ¯exibility within the IAG structure and allows for establishment of inter-commission/service bodies (i.e., for geodetic theory or techniques, which presently resides within commissions). Structure of the IAG Central bureau, IAG bureau, EC and Council. G. Beutler pointed out that the commission names were not ®xed by the proposal, and that he would appreciate input from EC members on this. It was strongly stressed that there should be no appointed members in the EC. Services, commissions and members can nominate members, which will subsequently be elected by the Council.

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The importance of the Council was stressed. A suggestion for improved communication between the EC and the Council would be to initiate informative meetings at the SA. Individual Membership and Nominations/Voting K. P. Schwarz introduced possible scenarios for IAG personal membership based on the IAVCEI model. It was clari®ed that the issue of personal membership is not necessarily linked to the review process, but that it would be advantageous to introduce it at the same time if the EC agrees to go this route. In the IAVCEI model, personal members have bene®ts (i.e. discounts on participation in General Assemblies and journal subscription, voting rights). The EC gave its approval in principle to develop a proposal for personal membership that has di€erent levels of membership fees (developing countries) and bene®ts. It also decided that voting rights should not be given to individual members. The proposal will have to be approved by the EC. Finally the EC agreed to invite I. Mueller and J. Kauba to join the review committee for ®nalising the proposal for IAG restructuring. 8. Scienti®c program for the IAG Scienti®c Assembly (SA) in Budapest K. P. Schwarz had prepared and distributed a proposal for the scienti®c program for the SA in Budapest in 2001. Four symposia are proposed, two of them will run in parallel every day. Friday will be devoted to the IAG restructuring. The possibility of awarding a prize for the best student presentation using the IAG fund was discussed. It was decided to publish all presented and poster papers whose mauscripts are available at the meeting on a CD without review. A selected number of representative papers will be reviewed for publication in the IAG/ Springer symposia series. The registration fees will be increased to include the cost of producing the proceedings. The review process should be strict to be representative of the quality of science that IAG stands for. J. Adam will be asked to serve as editor of the proceedings. It was left to the convenors to accept/reject abstracts and carry out the review process. Besides the CD containing all abstracts and remaining un-reviewed papers, there will be an ocial IAG CD containing mid term reports of the bodies (especially the SSG) of the IAG. 9. Collaboration with sister societies (FIG, ISPRS, etc) after IUSM It was stressed that the collaboration should be on the working level and as concrete as possible. Obvious collaboration should be co-sponsoring of each other's symposia. 10. ISPRS has requested support for becoming a member of ICSU The Bureau has issued a positive response to the ISPRS request for ICSU membership.

11. Report from the WG on Education The report of the WG was presented by C. Tscherning. It was questioned whether there should be any of teaching material, and it was agreed that only the functionality of the links from the homepage to the proposed material will be checked. C. Tscherning was elected as president of the Committee on Education. 12. Report from the Committee for Developing Countries (CDC) D. Blitzkow had found it dicult to make progress in the work. The goals of the former CDC had been reviewed, and a number of concrete activities were taking place in South America. Despite IAG had allocated USD 4000 to the CDC it was not at all sucient to start any meaningful activity due to the large cost of air-travel within Africa. A workshop will be organized in May 2000 in Sao Paulo on the South-American geoid cosponsored by the Int. Geoid Service (IgeS). G. Beutler referred to the position paper of J. Manning, which contained useful considerations concerning the developing countries. J.Manning had also pointed to the activities of the UN regional Cartographic Conferences. It was concluded that we have to start with local geodesists, and in this sense the schools were a good entry point. 13. Discussion of IAU recommendation E. Groten had informed the Bureau about the IAU request of having a reference value of the gravity potential for time-corrections. It was recommended to use the best current value. 14. Request from GALOS to Recognize Galo Carrera as an IAG Fellow GALOS had requested that the work of Galo Carrera was recoginzed by IAG. The EC decided to award him the fellowship of IAG. 15. IAU request of IAG representative to IAU Commission 19 Clark Wilson was proposed, and accepted. 16. IAG Sponsored meetings To be summarized from the IAG homepage. J. Manning has requested the IAG endorsement of a regional workshop in Mongolia. An IAG representative was requested. The meeting is recognized as a ®ne initiative, and J.Manning will be asked to represent IAG. A meeting on Recent Crustal Movements in Helsingfors in August has been organized, and could be in con¯ict with the Scienti®c Assembly. It was felt that the way in which the ®rst announcement of this meeting used the IAG name was inappropriate. This was conveyed to the organizers by M. Vermeer. S. Zerbini is advising the LOC with respect to the program. Com. XIV will sponsor the meeting. 17. IAG collaboration with EGS and AGU IAG SSG co-sponsorship is possible together with AGU/EGS at international meetings. This would be a way to achieved IAG goals. IAG SSG could be used as a bridge between AGU and EGS. IAG ought to be visible,

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by co-sponsering sessions etc. F. Sanso will contact AGU and EGS concerning collaboration. 18.Young author's award F. Sanso refered to the letter of P. Teunissen, editor-inchief of the JofG, which had been distributed in advance. Of the four candidates proposed. Dr. Xu. was unanimously chosen for his paper ``Biases and the accuracy of, and an alternative to, discrete nonlinear ®lters'', Published in JoG, Vol. 73, pp. 35±46, 1999. 19. Gravity ®eld service A meeting will be held in Milan concerning uni®cation of the three gravity services. BGI, IGS, IETC. NIMA might provide a new GDEM (SRTM (100±200 m)) to improve global gravity. The EC encouraged this initiative. 20. Next meetings Next EC meeting: (EGS 2001 26-30 of March) 30±31/3 2001. Major items will be IAG restructuring, and SA planning. Ole B. Andersen Meeting report of the IAG/IAPSO Joint Working Group on Geodetic E€ects of Nontidal Oceanic Processes held in conjugation with the EGS XXV General Assembly, Nice, France, April, 2000 The oceans have a major impact on global geophysical processes of the Earth. Nontidal changes in oceanic currents and ocean-bottom pressure have been shown to be a major source of polar motion excitation and also measurably change the length of the day. The changing mass distribution of the oceans causes the Earth's gravitational ®eld to change and causes the center-ofmass of the oceans to change which in turn causes the center-of-mass of the solid Earth to change. The changing mass distribution of the oceans also changes the load on the oceanic crust, thereby a€ecting both the vertical and horizontal position of observing stations located near the oceans. Products of oceanic general circulation models (OGCMs) have been used to study these and other geodetic e€ects of nontidal oceanic processes. Data assimilation systems similar to those employed in numerical weather prediction are beginning to be used with OGCMs to improve their ®delity. In the near future, time-varying gravitational ®eld measurements, which over the oceans can be interpreted as timevarying ocean-bottom pressure measurements, will be available from the CHAMP and GRACE satellites. The assimilation of these new data types into OGCMs can be expected to further improve the accuracy of global ocean models, and hence the accuracy of the predicted e€ects of oceanic processes on the Earth's rotation, deformation, gravitational ®eld, and geocenter. Recognizing the important role that nontidal oceanic processes play in Earth rotation dynamics, an IAG/ IAPSO Joint Working Group on Geodetic E€ects of Nontidal Oceanic Processes was formed at the XXII General Assembly of the IUGG in Birmingham. The

objective of this IAG/IAPSO Joint Working Group is to investigate the e€ects of nontidal oceanic processes on the Earth's rotation, deformation, gravitational ®eld, and geocenter, and to foster interactions between the geodetic and oceanographic communities in order to promote greater understanding of these e€ects. A meeting of this IAG/IAPSO Joint Working Group was held on April 27, 2000 in Nice, France in conjunction with the 25th General Assembly of the European Geophysical Society during which presentations were given by Rui Ponte, Chris Hughes, and Richard Gross. Rui Ponte discussed an oceanographic data assimilation system being created by collaborators from the Massachusetts Institute of Technology (MIT), the Scripps Institution of Oceanography, and the Jet Propulsion Laboratory. The ocean model component of the data assimilation system, originally developed at MIT, is currently run on a 2 ´ 2 degree horizontal grid with constant mixing coecients and a simple convective adjustment scheme. Future improvements will include ®ner resolution, more realistic mixed layer physics and eddy parameterizations, and relaxation of the volume conserving formulation. The oceanographic data currently being assimilated include altimetric measurements of sea surface height, hydrographic sections, and sea surface temperature measurements. Other types of data (e.g., ¯oats, XBT pro®les) will also be included in the future. Routine calculation of oceanic angular momentum and torque quantities from the output of the assimilation system is envisioned. Chris Hughes described the GLObal Undersea Pressure (GLOUP) data bank. For more information about GLOUP and/or to obtain the series of historical oceanbottom pressure measurements see the GLOUP home page at http://www.pol.ac.uk/psmslh/gloup/gloup.html. Richard Gross described the International Earth Rotation Service (IERS) Special Bureau for the Oceans (SBO). The IERS Special Bureau for the Oceans is one of seven Special Bureaus of the IERS Global Geophysical Fluids Center (GGFC) which was established on January 1, 1998 in order to help relate dynamical properties of the atmosphere, oceans, mantle, and core to motions of the Earth, including its rotation. In particular, the IERS Special Bureau for the Oceans is responsible for collecting, calculating, analyzing, archiving, and distributing data relating to nontidal changes in oceanic processes a€ecting the Earth's rotation, deformation, gravitational ®eld, and geocenter. The oceanic products available through the IERS SBO are produced primarily by general circulation models of the oceans that are operated by participating modeling groups and include oceanic angular momentum, center-of-mass, bottom pressure, and torques. Through the IERS SBO web site at http://euler.jpl.nasa.gov/sbo, oceanic data can be downloaded and a bibliography of publications pertaining to the e€ect of the oceans on the solid Earth can be obtained. Currently, two di€erent oceanic angular momentum data sets are available. The IERS SBO is therefore one possible source of data that can be used by the IAG/IAPSO Joint Working Group in their investigations on the geodetic e€ects of nontidal oceanic processes.

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Meetings of the IAG/IAPSO Joint Working Group on Geodetic E€ects of Nontidal Oceanic Processes are planned to be held twice-per-year in conjunction with major conferences in order to foster interactions on this topic between the geodetic and oceanographic communities. These meetings, which are open to all interested individuals, will generally be held in the Spring in conjunction with the EGS conference in Europe and in the Fall in conjunction with the Fall AGU conference in the United States. The next meeting will be held in conjunction with the Fall 2000 AGU conference in San Francisco, California during December 15±19, 2000 with the exact date and time to be announced later. In order to receive announcements about this and all future meetings, please contact Richard Gross by sending an e-mail message to him at [email protected]. R. Gross Working Meeting of the IAG SSG 4.190 on Non-Probabilistic Assessment in Geodetic Data Analysis The ®rst working meeting of the IAG SSG 4.190 took place at the Geodetic Institute, University of Karlsruhe (GIK), on April 7, 2000. 11 members and corresponding members were participating. The meeting was opened with a welcome note by B. Heck, president of the IAG Section IV on General Theory and Methodology. H. Kutterer, chairman of the SSG, continued with a short review of the terms of reference and objectives. The main part of the meeting consisted of oral presentations by members of the SSG on the topics fuzzy-theory (E. A. Shyllon, K. Heine), robust estimation (A. Carosio), arti®cial neural networks (J. B. Miima), interval mathematics (S. SchoÈn), GIS for local geoid computation (M. Brovelli), and on general uncertainty theory (H. Kutterer). It was decided to have annual closed working meetings of the SSG. Besides, it is planned to organize an open international workshop on robust and fuzzy techniques in March 2001 in ZuÈrich. The ®nancial support of the stay of E. A. Shyllon by the IAG is gratefully acknowledged as well as the sponsoring of the organization of the meeting by the GIK. H. Kutterer Meeting information IAG Scienti®c Assembly Budapest, Hungary 3±7 September, 2001 Sponsor: IAG First circular and information is available at http:// www.sztaki.hu/conferences/iag2001

Invitation The International Association of Geodesy (IAG), one of the member associations of the International Union of Geodesy and Geophysics (IUGG) will hold its Scienti®c Assembly in the capital of Hungary, Budapest from September 2nd to 8th, 2001, in response to an invitation of the IAG Section of the Hungarian National Committee for the IUGG. The scienti®c symposia and associated meetings will be held at the building of the Hungarian Academy of Sciences, HAS. Pre-and post symposia programs will be organized in order to support the discovery of Hungary's unique cultural treasures and its challenging natural environment. All scientists interested in IAG activities are cordially invited to participate in the Scienti®c Assembly in Hungary in 2001. The new millennium has an outstanding signi®cance for the host country, Hungary, which celebrates the 1000th anniversary of its statehood as well as of the adoption of Christianity. Bordered by Austria, Croatia, Romania, Serbia and Montenegro, Slovakia, Slovenia and Ukraine, Hungary is the heart of Central Europe. Located at the crossroads of all these di€erent cultures, Hungary provides a perfect bridge between Eastern and Western Europe. The LOC would like to combine the high-level scienti®c and technical content of the Scienti®c Assembly with the culture of Hungary and hopes to be a good host to all Assembly participants. At the very beginning of the new Millennium the Scienti®c Assembly hopefully will attract participants from all over the world. Scienti®c Program The scienti®c program, under the title ``Vistas for Geodesy in the New Millennium'', will emphasize the interaction of geodesy with the other earth sciences and engineering, and its growing contribution to the modeling of the System Earth. It will highlight the impact of major new satellite missions and the integration of new data sources with existing ones. The program will be open for new ideas, the planning of new programs, the integration of new people, and the creation of new ¯exible organizational structures. A major e€ort will be made to attract a large number of graduate and undergraduate students to share the new vistas for geodesy. Special IAG Council Meeting As decided at the last General Assembly of the IAG in Birmingham in 1999, a special IAG Council Meeting will take place in conjunction with this Scienti®c Assembly in order to decide on possible re-structuring of the IAG. More information More information is available at http://www.sztaki.hu/ conferences/iag2001 7th International Winter Seminar on Geodynamics: Viscoelastic Theories in Geodynamics Sopron, Hungary 19±23 February, 2001 Sponsor: IAG More info can be found at http://www.ggki.hu/a/

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International Symposium on Vertical Reference Systems February 20±23, 2001 Cartagena, Colombia Sponsor: IAG More info can be found at http://codazzi9.igac.gov.co/ veres.html IAG International symposium on Recent crustal movements Helsinki, Finland, August 27±31, 2001 More info can be found at: http://www.g®.®./SRCM Fourth International Symposium on ``Turkish-German Joint Geodetic Days'' Berlin, Germany April 3±6, 2001 More information can be found at: http://www.ins. itu.edu.tr/jeodezi/fotog/tgjgd/index.html Book Review title: authors: publisher: orders to: Rooseveltova ISBN: year:

Space Geodesy and Space Geodynamics Milan Bursa and Jan Kostelecky Ministry of Defence of the Czech Republic Dr. D. Dusatko, Military Geographic Institute, 23, 161 01 Praha 6, Czech Republic 80-86049-95-7/80-85469-78-2 1999

pages: size: details:

459 16.5  24 cm hard cover ± english translation

The book comprises 459 pages and consists of the following chapters: De®nition, Historical Evolution of the Subject; Systems of Coordinates; Equations of Motion of a Satellite and Their Solution; Gravitational and Gravity Potential at Points of the Earth's Surface and in Outer Space; Motion of an Arti®cial Satellite in the Gravitational Field of the Earth, Moon and Sun; Methods and Achievements of Satellite Geodesy; Principles of Space Geodynamics. From the two main topics making up the title of the book, the authors, in agreement with current terminology, seem to understand space geodesy as: · motion of a satellite orbiting around the Earth in a mathematically de®ned gravitational ®eld under perturbation by the attraction of Moon and Sun; · modern observational satellite methods, from satellite laser ranging and GPS to VLBI and gradiometry; · geodetic results achieved and/or achievable by such methods,including Earth parameters and Geodetic Reference Systems; and space geodynamics as the study of temporal variations of the Earth and its gravity ®eld: · Earth rotation and polar motion, as well as precession and nutation; · treatment of the Earth as a deformable body; · Earth tides; · tidal deformation of the Earth and its gravity ®eld; · continental drift and plate tectonics; · satellite altimetry and sea surface topography. The two topics of the book are by no means separated: space techniques such as Satellite Laser Ranging and VLBI are used for measuring continental drift as well as for establishing precise positions and gravitational reference models. Both authors are well known for their original contributions to these topics over several decades. The standard topics thus are well treated, but also topics less frequently found in the textbook literature are considered, so the search of original literature is considerably reduced; it is also facilitated by an extensive bibliography. The book is well readable, the structure is logical, the content is very comprehensive and rich, and many numerical values, dicult to ®nd elsewhere, give the book a special applicational value. Such a synthesis of space geodesy and geodynamics is unique in the geodetic literature. This very informative book ®lls a de®nite need and can be highly recommended to every student and researcher working in this ®eld. Helmut Moritz