On the vision of an
International Altimeter Service (IAS)
Invitation to discuss the IAS
Wolfgang Bosch,
bosch@dgfi.badw.de
Rationale for IAS (top-down)
• Focus on Global Earth Observing Systems (GEOS) to
be coordinated by GEOSS, a system of systems
• G4OS:
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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
OST Science Team Meeting, Hobart, March 12-15, 2007
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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?
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OST Science Team Meeting, Hobart, March 12-15, 2007
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
OST Science Team Meeting, Hobart, March 12-15, 2007
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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
OST Science Team Meeting, Hobart, March 12-15, 2007
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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
OST Science Team Meeting, Hobart, March 12-15, 2007
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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-stopshop“ for users
• IAS shall cover the entire spectrum of altimetry
applications, including all surface types (ice, lakes, land)
OST Science Team Meeting, Hobart, March 12-15, 2007
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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.doc
OST Science Team Meeting, Hobart, March 12-15, 2007
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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
OST Science Team Meeting, Hobart, March 12-15, 2007
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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, G4OS and other
bodies
OST Science Team Meeting, Hobart, March 12-15, 2007
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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.
OST Science Team Meeting, Hobart, March 12-15, 2007
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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)
OST Science Team Meeting, Hobart, March 12-15, 2007
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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, … ?
OST Science Team Meeting, Hobart, March 12-15, 2007
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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
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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?
OST Science Team Meeting, Hobart, March 12-15, 2007
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OST Science Team Meeting, Hobart, March 12-15, 2007
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