The International Association of Geodesy (IAG) is informing all concerned scientists and research Institutes that the post of Director of the “International Centre for Earth Tides” (ICET) will become vacant on January first 2008. ICET is one of the IAG Services integrated inside the “International Gravity Field Service” (IGFS). ICET is a member of the Federation of Astronomical and Geophysical Data Analysis Services (FAGS) and a World Data Center.

Interested persons will find in the following document an overview of the responsibilities and activities of ICET. More information can be found on the ICET WEB site http://www.astro.oma.be/ICET, or obtained directly from the ICET Director Prof. Bernard Ducarme (ducarme@oma.be).

An application letter should be sent to Prof. Carl Christian Tscherning, IAG General Secretary, (e-mail: iag@gfy.ku.dk) with a description of the long term project foreseen for ICET and the commitment of its new host institution. A copy should be sent to Prof. Gerhard Jentzsch (Gerhard.jentzsch@uni-jena.de), President of ICET Directing board. The proposal should be submitted before June 1st 2007.

ICET terms of reference

The terms of reference of the International Centre for Earth Tides (ICET) can be summarised as follows:

• to collect all available measurements on Earth tides, as World Data Centre;
• to evaluate these data by convenient methods of analysis in order to reduce the very large amount of measurements to a limited number of parameters which should contain all the desired and needed geophysical information;
• to compare the data from different instruments and different stations distributed all over the world, evaluate their precision and accuracy from the point of view of internal errors as well as external errors;
• to help solving the basic problem of calibration by organizing reference stations or realizing calibration devices;
• to fill gaps in information and data;
• to build a data bank allowing immediate and easy comparison of earth tides parameters with different Earth models and other geodetic and geophysical parameters ;
• to ensure a broad diffusion of the results and information to all interested laboratories and individual scientists.

Main activities

These goals are achieved essentially by the diffusion of information and software, the data processing, the training of young scientists and the welcome of visiting scientists.

ICET has also a long term “Research Project”. Since 1997, ICET is fostering the development of the “Global Geodynamics Project” (GGP), a permanent network of superconducting gravimeters able to observe inertial and gravitational accelerations at the surface of the Earth from seismic periods up to polar motion. ICET has an agreement with the GeoForsghungZentrum (GFZ) Potsdam for the administration of the GGP data base and is responsible for preprocessing and analyzing the tidal data. It represents 90% of the incoming data.

ICET is publishing each year at least one issue the “Bulletin d’Information des Marées Terrestres (BIM)” with original scientific papers. Besides general information including historical aspects and ICET reports, the ICET WEB site gives access to:

• the general bibliography on Earth Tides from 1870-1997;
• the table of content of all the BIM issues, and starting from BIM 133, year 2000, an electronic version of the papers;
• various tidal analysis and preprocessing software available from different WEB sites or on request from ICET;
• various products.

More details on the ongoing activities can be found on the management section of the WEB site.

Requirements

The ICET Director has to be a scientist able to devote a part of his activity to ICET. The task can be shared with other scientists. A scientific expertise in Earth tides is required. Technical support is required for the data reduction and analysis, the ICET and GGP data base maintenance and the updating of the ICET WEB site. From our experience there is enough work for a full time technician, depending of course of the number of involved scientists.

This staff has to be fully supported by the host Institution. Additional costs, such as the publication of the BIM, have also to be supported by the host institution, as ICET is only receiving a slight financial support through the Federation of Astronomical and Geophysical data analysis Services (FAGS). Figures concerning the yearly expenses can be found in the annual reports (see management section on the WEB site).

The applicants should submit a business plan including:

• a presentation of the Director and his staff;
• a budget;
• a planning of activities for the following years;
• a formal commitment of the responsible of the Institute.

C.C.Tscherning, IAG Secretary General.