*************************************************************************** Gazette IERS Gazette IERS Gazette IERS Gazette IERS Gazette _____________________________________ No 14, 21 February 1997 / ____________________________________/ Contact: iers@obspm.fr ftp: hpvlbi.obspm.fr (145.238.100.7) WWW: ftp://hpvlbi.obspm.fr/iers/ierscb.html *************************************************************************** INTERNATIONAL EARTH ROTATION SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE CALL FOR PROPOSALS COORDINATING CENTER ENTITLED "MONITORING GLOBAL GEOPHYSICAL FLUIDS" The International Earth Rotation Service requests proposals for participations in a Coordinating Center that would help relate properties of the various global geophysical fluids to motions of the Earth, including those of its three-dimensional rotation vector. The major Earth system fluid components, namely the atmosphere, ocean, and the core are known to participate in forcing motions of the Earth, including Earth rotation and polar motion, and to modify the gravitational fields and the motions of the Geocenter. Also, ancillary aspects of properties of the fluids such as the atmosphere, must be considered to properly interpret signals derived from the techniques of space geodesy relevant to the IERS mission. Moreover, effects of the ocean tides comprise a special type of forcing by the oceans. The Coordinating Center for Monitoring Global Geophysical Fluids is an extension of the Sub-Bureau for Atmospheric Angular Momentum, in existence since 1989. During this period a great deal of research has demonstrated the significance of atmospheric forcing on the Earth's rotation variations. The roles of other geophysical fluids have recently become evident too, and now this will be recognized formally within the IERS. Also, the Coordinating Center will deal with torques and gravitational field changes due to the fluid mass transports, in addition to angular momentum, and all these elements will be an integral part of computation and data management of the Center. For this Coordinating Center for Monitoring Global Geophysical Fluids, and consequently its sub-centers, there is a need to receive or calculate, distribute, archive, and analyze data related to each of the fluids for Earth rotation-related purposes. The IERS anticipates a need for a Coordinator for the Center for Monitoring Global Geophysical Fluids, as well as for personnel who will participate in the activities of its various subcenters, including the subcenter for the atmosphere, for the ocean, for ocean tides, for the core, and for the geocenter and gravitational fields. Such participants may include directors of each of the five sub-centers, as well as scientists who will provide data and analyses to the subcenters. The Coordinating Center for Monitoring Global Geophysical Fluids and its five subcenters need not be housed in the same institution. The Center will be involved in all technical and administrative activities defined below. The IERS anticipates that the role of the Coordinator for Monitoring Global Geophysical Fluids will be as follows. - To maintain contact with each of the five subcenters, and ensure that the primary datasets from each of the centers are available to the IERS centers and users. - To report on behalf of all activities of the Coordinating Center to the IERS Directing Board and participate in Board meetings as a member. - To organize unified approaches to analysis and data handling among the five subcenters, so far as possible. - To help organize special campaigns as needed in coordination with other IERS elements. - To cooperate with the Technique Coordinators for the provision of geophysical data needed for the treatment of space geodesy observations, and with the Central Bureau on circulation of information. The role of Sub-Center Directors will be: - To receive or calculate, archive, distribute and analyze geophysical fluid data related to the subcenter. - To maintain liaisons with both the head of the Coordinating Center for Monitoring Global Geophysical Fluids and with scientists who produce data within the discipline of the coordinating center. An overview of the five sub-centers is outlined in the Appendix. ----- Proposals for participation in the IERS Coordinating Center entitled "Monitoring of Global Geophysical Fluids" and its sub-centers should be submitted by 30 June 1997, to: Christoph Reigber Chairman, IERS Directing Board GFZ Potsdam Bereich 1, Telegrafenberg A17 D-14473 Potsdam, Germany Telephone 49 331 288 11 00 Fax 49 331 288 11 11 Internet reigber@gfz-potsdam.de with copy to: Martine Feissel Secretary, IERS Directing Board Observatoire de Paris 61 Avenue de l'Observatoire 75014 Paris, France Telephone 33 (0)1 40 51 22 26 Fax 33 (0)1 40 51 22 91 Internet feissel@obspm.fr The submissions should list the resources available to support the proposed activity. As the IERS cannot provide financial resources, the commitment of institutions hosting the proposed Coordinating Center and Sub-Centers will be an important consideration in the proposal review. The IERS Directing Board will review the proposals and make the selection at its September 1997 meeting. ----- This text and its Appendix are available under anonymous ftp at 145.238.100.7 (hpvlbi.obspm.fr), file:iers/info/gazette.14 or via WWW with netscape, ftp://hpvlbi.obspm.fr/iers/ierscb.html click 'IERS communications and publications' ______________________________________________________________________________ Appendix: Tasks as coordinator or as sub-center participants for the new Coordinating Center entitled 'Monitoring of Global Geophysical Fluids' Tasks foreseen for the different sub-centers of the Coordinating Center for Monitoring Geophysical Fluids are the following. Sub-Center for the Atmosphere (SCA) ----------------------------------- 1. To continue the present activities of the Sub-Bureau for Atmospheric Angular Momentum (SBAAM): - to collect and archive meteorological data used for AAM: - wind vector (from zonal wind and meridional wind), - mass term (from surface pressure); - to integrate them at different vertical levels in the atmosphere, - to compute the AAM with two options: - modeling with a perfect Inverted Barometer Ocean (IBO), - modeling with a Non-Inverted Barometer Ocean (NIBO); - to collect, archive and compute zonal mean wind, zonal mean temperature, and spherical harmonics of surface pressure. 2. To continue to look for new data to improve the AAM computation: - new data based on new considerations for the air/sea interface; - new data based on techniques to directly monitor the winds in the upper atmosphere; - new atmospheric data centers; - consideration for a new time interval between the data (less than 6 hours) for getting sub-diurnal AAM; - consideration for an increasing data span, i.e. to continue the analysis of the historical meteorological observations. 3. To look for new data relative to the atmosphere and which are of interest for the space geodesy and meteorology communities: - new space-based data for examining the temperature and humidity; - new parameters as - water vapor (zenith path delay) data based on radio- metric techniques such as VLBI, GPS, ..., - ionosphere TEC (Total Electron Content) based on radio-signal analyses. 4. To interact with the Sub-Center for the Ocean (SCO) which should look for a better modeling of the interaction between ocean and atmosphere, not only Inverted Barometer/Non-Inverted barometer (IBO/NIBO), but also dynamical ocean. 5. To make a synthesis of the various values of AAM by forming a combination AAM series. 6. To implement computations of not only AAM but torques. 7. To compute the effects of the atmosphere on the variations of the Length-Of-Day (LOD), of the polar motion, of the precession/nutation, of the geocenter, and of the the gravitational field. 8. To document the data by creating and maintaining online information files (with: when and which modifications in the atmospheric analysis systems, explanation of possible discontinuities in the series, summaries of the individual model characteristics, commentary on changes to the systems that may affect the AAM computation,...). 9. To compute the loading effects induced by the atmosphere on the solid Earth and the associated changes in the Earth Orientation Parameters (EOP), in the geocenter position and on the gravitational field. Sub-Center for the Ocean (SCO) ------------------------------ 1. To address the following request to research groups doing Global Circulation Models (GCM) or satellite altimetry: - to consider ocean heights and currents in the different time scales where the ocean can be important for Earth Orientation Parameters (EOP) and geocenter and gravitational field variations (mostly seasonal and daily and sub-daily time scales); - to incorporate computations of ocean AM and geocenter motion in model runs; - to send the results to the Sub-Center for the Ocean (SCO) with documentation (on the hypothesis concerning the ocean/atmosphere interaction, on the close-up of the hydrological cycle...); - eventually to incorporate torque computations. 2. To stimulate the ocean loading computations and the associated effects on the EOP, on the geocenter position and on the gravitational field. 3. To collect and archive these data, with the given documentation, or eventually ftp-sites where they are available. 4. To look for a better modeling of the interaction between ocean and atmosphere (not only Inverted barometer/Non-inverted barometer (IBO/NIBO), but also dynamical ocean), and to interact with the Sub-Center for the Atmosphere (SCA) for this point. 5. To encourage the ocean loading computations and the associated effects on the EOP, on the geocenter position and on the gravitational field. Sub-Center for the Ocean Tide (SCOT) ------------------------------------ 1. To collect information about ocean tide models. 2. To address the following request to research groups doing ocean tide models (using satellite altimetry data, tidal gauge data, finite element models, and/or hydrodynamic models): - to consider ocean heights and currents in the different tidal time scales (zonal long period tides, diurnal tesseral tides, and semi-diurnal sectorial tides); - to incorporate computations of ocean tide AM and geocenter motion in the runs; - to compute ocean tide effects on EOP and on the geocenter and the gravitational field; - to send the results to the Sub-Center for the Ocean Tide (SCOT) with documentations (on what kind of data, what kind of constraint, which hypotheses for the models...); - eventually to incorporate torque computations. 3. To compare them by means of validation against satellite altimetry data, tidal gauge data, solid Earth tides (ocean loading effects). 4. To produce a standard model. 5. To encourage the tidal ocean loading computations and the associated effects on the EOP, on the geocenter position and on the gravitational field. Sub-Center for the Core (SCC) ----------------------------- 1. To seek results from research on Core-Mantle coupling, geomagnetism, core fluxes, ...etc. concentrating on the relation with decade fluctuation of LOD. 2. To seek results from research on Core-Mantle coupling, core fluxes, ...etc. concentrating on the diurnal time scale in relation with the Free Core Nutation (FCN) and the Free Inner Core Nutation (FICN, also noted PFCN). 3. To seek results from research on core modes and interaction with the inner core, in relation with the EOP. 4. To summarize that information. Sub-Center for Geocenter and Gravitational field (SCGG) ------------------------------------------------------- 1. To collect and archive positions of the geocenter from satellite geodesy, together with proper documentation (e.g. way they are determined), with a particular attention on the IERS Geocenter motion Campaign (see Call for proposals in the IERS Gazette 10 of 2 January 1997). 2. To collect and archive data and/or make note of the ftp sites where they are available, of the gravitational field and also of the time variation of its components. 3. To emphasize the importance of the geophysical studies related to the geocenter motion and the gravitational field variation and to encourage related particular campaigns. 4. To interact with the other sub-centers computing effects on the geocenter and on the gravitational field. _____________________________________________________________________________ Note: The data from all sub-centers should be electronically accessible, such as by anonymous ftp, and should contain on-line information (README) files. _____________________________________________________________________________