1. On the vision of an International Altimeter Service (IAS) Invitation to discuss the IAS Wolfgang Bosch, bosch@dgfi.badw.de On the vision of an International Altimeter Service (IAS) Invitation to discuss the IAS Wolfgang Bosch, bosch@dgfi.badw.de

2. OST Science Team Meeting, Hobart, March 12-15, 2007 2 Rationale for IAS (top-down) Focus on Global Earth Observing Systems (GEOS) to be coordinated by GEOSS, a system of systems G 4 OS: –GOOS for the Ocean –GCOS for Climate –GTOS for the terrestrial Component, and –GGOS for the geodetic component Due to its many interdisciplinary applications for oceanography, marine geophysics, the Earth gravity field, the Earth rotation, … satellite altimetry has to be a mandatory element of GEOS

3. OST Science Team Meeting, Hobart, March 12-15, 2007 3 Rationale for IAS (bottom-up) There are already (many and excellent) services for satellite altimetry, but in spite of that users are sometimes lost in hyperspace –Differences between MGDR-C (CNES) and MGB (NASA) known? –Where can users find the most reliable estimate of range biases of Jason1 or ENVISAT? –Why are all users forced to perform their own upgrade for new orbits (due to improved gravity fields) and new correction models (tides, SSB, wet tropo)? –Should a user take KMS04 or CLS01 or DSNC07? –Why are there different formats for the marine gravity data ( S&S and DNSC)? –Where to get informed about different estimates of the Mean Dynamic Ocean Topography?

4. OST Science Team Meeting, Hobart, March 12-15, 2007 4 IGS – a model for IAS ? Motivation for IAS derived from IGS (International Global Navigation Satellite Systems Service), successfully realised –By voluntary cooperation of many organisations using –Standards for observation (RINEX) and solutions (SINEX) Acknowledge! Without IGS (ILRS, IVS) we would miss –Precise orbits of altimeter satellites –Definition and maintenance of International Terrestrial Reference Frame (ITRF) – crucial for investigating any long-term evolution of the sea level

5. OST Science Team Meeting, Hobart, March 12-15, 2007 5 Experiences from IGS and other services Once a Service is established it gets its own dynamic To contribute to a service may help to request external funds Existence and impact of services did help to avoid reduction of space techniques

6. OST Science Team Meeting, Hobart, March 12-15, 2007 6 IAS Planning Group (IAS-PG) Initiated in 2003 by a Call of C.K. Shum, Ph. Woodworth, G. Mitchum, and W.Bosch hosted by IAG, Commission1 „Reference Systems“ == COSPAR Subcommission „Coordination of Space Techniques“ Official endorsements by –Global Sea Level Observing System GLOSS(IOC) –International Association of Geodesy, IAG –International Association of the Physical Sciences of the Oceans, IAPSO

7. OST Science Team Meeting, Hobart, March 12-15, 2007 7 IAS-PG Conclusions General agreement: an Altimetry Service is useful and should be created IAS shall be built upon voluntary contributions and integrate (and extend) existing services IAS shall coordinate, leaving processing and data storage at different institutions/centres IAS shall provide a single point-of-contact, a „one-stop- shop“ for users IAS shall cover the entire spectrum of altimetry applications, including all surface types (ice, lakes, land)

8. OST Science Team Meeting, Hobart, March 12-15, 2007 8 First attempt towards an IAS Drafting IAS Terms of References 1) with structure and organisation similar to other services IAS splinter in Venice 2006: No consensus on this ToR –organisational overhead (Governing Board) not accepted –no organisation ready to operate a Central Bureau –IAS objectives too imprecise (what data what products?) New attempt (one step back): –The IAS organisation needs to be reviewed –focus should be on pilot projects demonstrating value adding to existing services 1) http://www.dgfi.badw.de/wiki/Documents/IAS-TOR-06-02-14.dochttp://www.dgfi.badw.de/wiki/Documents/IAS-TOR-06-02-14.doc

9. OST Science Team Meeting, Hobart, March 12-15, 2007 9 Call for an IAS- Integrating Office (IAS-IO) Submitted on January, 15, 2007 seeking proposals for the establishment of an IAS-Integrating Office with the general objectives –to provide a single point of contact for information on satellite altimetry and its applications; –to communicate with, and interface to, mission data providers, centres which process, archive, and analyse altimeter data, and other related services/organizations; –to promote satellite altimetry as a core element of Global Earth Observing Systems

10. OST Science Team Meeting, Hobart, March 12-15, 2007 10 IAS-IO shall accomplish its mission by Collaborating with space agencies, processing centres, research institutes, altimeter experts Establishing a collaborative Web site (Wiki or Content Management System) (a single point-of-contact) Directing user requests to the appropriate organizations (IAS a mediator) Establishing pilot projects to enhance and expand its activities (may evolve to permanent components of IAS) Reporting to IAG, IAPSO, GLOSS, GEOSS, G 4 OS and other bodies

11. OST Science Team Meeting, Hobart, March 12-15, 2007 11 The roadmap for IAS-IO Proposals will be reviewed by the Nomination Committee (NC, representatives of IAG, IAPSO, GLOSS, related services) One of the applicants shall be recommended to take the lead of the IAS-IO The NC may suggest a list of intial tasks and value-adding activities of the IAS-IO.

12. OST Science Team Meeting, Hobart, March 12-15, 2007 12 Suggestions for IAS-Pilot projects Distributed (on-request) upgrade of GDR data by retracked data, new orbits and/or correction models –Can take advantage of high granularity of GDRs –Decomposition and re-merging of GDRs easy –Sharing distributed resources e.g. by GRID technology, Harmonisation or common user interface for marine gravity data New compilation of global ocean tides models. If possible complete this collection by regional tide models and provide uniform interfaces Improvements of tides in shallow water (empirically and/or by assimilation into regional models)

13. OST Science Team Meeting, Hobart, March 12-15, 2007 13 IAS in the context of CAGS and ICSU At present, services are operating under the umbrella of the Committee on Astronomical and Geophysical Services, CAGS (formerly FAGS) Future role of CAGS unclear, to be reviewed in 2 years by the International Council of Scientific Unions, ICSU) ICSU Priority Area Assessment (PAA) focuses on Scientific Data and Information (SciDIF). Integration of IGS, ILRS, IVS, IAS, … ?

14. OST Science Team Meeting, Hobart, March 12-15, 2007 14 Possible funding of IAS-IO activities U.S. funding situation not known. In the European context there are Open Call’s for financing networking, meetings, conferences, and scientific exchange for Earth System Science COST action of the European Science Foundation Participation of at least five COST member states required Clould be CLS, NOC, DNSC, DEOS + German Group. Two stage procedure with preliminary/final proposals. Deadline for preliminary proposals is March 30! Interested?

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