[IGSMAIL-3370]: GPS Tide Gauge Benchmark Monitoring Pilot Project / Call for Participation
Tilo Schoene
tschoene at gfz-potsdam.de
Wed Jun 6 08:25:04 PDT 2001
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IGS Electronic Mail 06 Jun 08:30:38 PDT 2001 Message Number 3370
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Author: Tilo Schoene, GFZ Potsdam
Dear colleagues,
please find attached a Call for Participation for the GPS Tide Gauge
Benchmark Monitoring Pilot Project. You may download a pdf-version of
the document at http://op.gfz-potsdam.de/staff/schoene/TIGA_CfP.pdf .
Sincerely,
Tilo Schoene
Chair TIGA Pilot Project Committee
INTERNATIONAL GPS SERVICE
CALL FOR PARTICIPATION
GPS Tide Gauge Benchmark Monitoring Pilot Project
(TIGA - PP)
* Letter from Chair on behalf of WG
Dear Colleague:
The IGS plays a significant role in promoting, establishing
and the densification of a global reference system. More-
over, coordinates published and distributed by the IGS are
used in numerous scientific applications, ranging from plate
tectonic studies to atmospheric sounding. In contrast, since
the beginning of the GPS era several studies have revealed
the uncertainty in the GPS height component. Especially when
studying sea level changes, where the GPS height of the
benchmark is used for defining an absolute sea level datum,
problems occur when correcting the time series for height
changes of the benchmark.
Addressing the height component in routine computation and
establishing and maintaining new geodetic ties to tide
gauge systems will be further an important contribution to
climate change studies. With the TIGA Pilot Project as
described in the attached Call for Participation the IGS
will again provide its expertise to a new field of
scientific application.
For the first time it is not the intention of the IGS to
provide results with a very low latency, but to have as
much as possible stations included. The Pilot Project
committee hopes that through this strategy new scientific
applications will be driven.
Participation in this IGS activity is open to governmental
agencies, educational and research institutions and other
organizations whose financial resources allow a firm
commitment to be made in support of TIGA. Proposals may be
submitted at any time during the period ending on August 1,
2001.
The enclosed document provides information on the
participation solicited, where existing components will
assume expanded roles and functions, and where new groups
or components may be interested in contributing. Proposals
may address single or multiple aspects of TIGA for which
the proposing organization has the capability and capacity
to support.
Organizations interested in participating in the TIGA
activities should submit a Letter of Intent by July 1,
2001, expressing their interest. IGS will offer full
cooperation to groups involved in the development of
support capabilities for TIGA. Participants in current
activities are also strongly encouraged to respond to this
solicitation.
Your interest and cooperation in participating in this
international effort are welcomed and highly appreciated.
Please feel free to contact the IGS Central Bureau or
myself with questions or comments regarding this Call.
Sincerely Yours,
Tilo Schoene
Description of the Proposal
* Background
The GPS Tide Gauge Benchmark Monitoring - Pilot Project
(TIGA-PP) is a pilot study of the International GPS Service
(IGS) for establishing a service to analyze GPS data from
stations at or near tide gauges (TG) on a continuous basis
(CGPS @ TG). It was approved by the IGS Governing Board at
its 16th meeting (March 25, 2001). The primary product of
the service is time series of coordinates for analyzing
vertical motions of Tide Gauges and Tide Gauge Benchmarks
(TGBM). All products are made public to support and
encourage other applications, e.g. sea level studies. In
particular, the products of the service facilitate the
distinction between absolute and relative sea level changes
by accounting for the vertical uplift of the station, and
are, therefore, an important contribution to climate change
studies. The service may further contribute to the
calibration of satellite altimeters and other oceanographic
activities. The pilot project will operate for a period up
to three years, from 2001 to 2004. After this period the
IGS Governing Board will evaluate the project and decide
whether or not this activity should become a regular IGS
service function.
* Goals
The IGS has the experience and infrastructure as well as a
stated interest to become involved in the activities for
GPS continuous monitoring of tide gauge benchmarks. With
its global distribution, the IGS network at tide gauges may
become the frame for regional activities, too, like
European Sea Level Service (ESEAS) or other regional
networks.
The goals of the TIGA-PP are identified as follows:
1. Establish, maintain and expand a global CGPS @ TG network
- Select a set of GPS-equipped tide gauges with a long
and reliable history practicable for both sea level
change studies and satellite altimeter calibrations.
- Apply IGS network operation standards.
- Promote the establishment of more continuously
operating GPS stations in particular in the southern
hemisphere.
- Promote the establishment of links to other sites
which may contribute to vertical motion determination,
e.g., DORIS, SLR, VLBI, and/or absolute gravity
stations.
- Develop recommendations for a minimum technical
standard of the whole tide gauge system to be included
into the Pilot Study, e.g., sensor types, the nature
of the leveling program, and metadata documentation.
2. Contribute to the procedures in which IGS realizes a
global reference frame in order to improve its utility
for global vertical geodesy. This may involve
reprocessing a significant subset of the (past and
present) IGS global tracking data set.
3. Compute precise station coordinates and velocities for
the CGPS @ TG stations using a processing stream that
runs months behind real-time in order to include the
largest possible number of stations. This effort will
incorporate all previously collected GPS data at each
CGPS @ TG station. Later on the combined solution will
have a maximum latency of one year.
4. Establish a secondary processing stream with much reduced
latency in order to support operational activities that
cannot tolerate large processing delays.
5. Monitor the stability of the network.
* Objectives
Since the success of TIGA-PP depends on two different
sensors, GPS and tide gauges, the accuracy of both have to
be evaluated. A total system error budget, including
various TG instrumentations, will be explored and defined
within the project period.
Currently a wide range of different tide gauge systems are
in operation, ranging from traditional floating gauges to
advanced acoustic and pressure systems. Often scientific
applications can only be run by using data 'as they are
provided'. However, it is expected that the IAG Special
Commission 8 (CGPS @ TG) will recommend standards for the
scientific implementation of GPS-equipped tide gauge
systems. The TIGA-PP Committee will promote such efforts
and will take actions to popularize such recommendations.
Although a new IGS site log file is currently under
development, the information herein is insufficient for sea
level related studies. The TIGA-PP Committee in cooperation
with the appropriate bodies of the TG community will
develop an augmented version of the site log to overcome
certain limitations.
According to studies by, e.g., Guy Woppelmann, for certain
tide gauges no ties exist to nearby GPS stations. The Pilot
Project Committee will identify such stations and also take
action to encourage and help with local ties.
GPS and other space geodetic techniques are only one tool
for the determination of vertical motion rates. A strong
preference is given to CGPS @ TG stations near absolute
gravity sites, if possible equipped with superconducting
gravity meters to account for short-term variations. If
such points are available in the vicinity, ties will be
encouraged.
Tide Gauge Data Centers (e.g. PSMSL, UHSLC, NTF) will be
requested to support the establishment of a common tide
gauge data format for stations participating in the TIGA-
PP. The data centers will further be requested to store and
make available the additional meteorological data provided
by participating stations.
* Organizational Aspects
The Call for Participation is released to enlist the
participation of current IGS network stations, Analysis
Centers, and Data Centers, as well as to solicit the
participation of new stations and Analysis Centers. The IGS
Central Bureau is asked to accept the increased
responsibility resulting from the inclusion of the pilot
service within the IGS. The Pilot Project will include
stations that meet IGS network requirements. The timeliness
for collecting data will be less stringent compared to
standard IGS operations to allow remote stations to
participate. The Pilot Project Committee, the IAG Special
Commission 8 (CGPS @ TG) and the PSMSL are responsible for
selecting the final set of stations.
* Project Committee
The TIGA-PP Committee is responsible for establishing and
managing the service during the pilot period. The members
are:
- Trevor Baker, POL
- Mike Bevis, University of Hawaii (Chair CGPS @ TG)
- Claude Boucher, IGN
- Remi Ferland, NRCan
- Bruce Haines, JPL
- John Manning, AUSLIG
- Gary Mitchum, University of South Florida
- Angelyn Moore, IGS Central Bureau (Network)
- Ruth Neilan, IGS Central Bureau, Director (ex officio)
- Steve Nerem, University of Colorado
- Christoph Reigber, GFZ Potsdam, (Chairman IGS GB)
- Wolfgang Scherer, NTF
- Tilo Schoene, GFZ Potsdam (chair of TIGA-PP)
- C.K. Shum, Ohio State University
- Guy Woppelmann, University La Rochelle
- Philip Woodworth, PSMSL
The Committee may ask other bodies or individuals to
provide their expertise and to review proposals throughout
the whole project.
The TIGA-PP Committee will evaluate, review and approve
proposals solicited in terms of science applications for
stations to be included, Analysis Centers and Data Centers
taking appropriate actions as necessary. The descriptions
and responsibilities of these fundamental IGS components
are defined in the Terms of Reference
(http://igscb.jpl.nasa.gov/organization/bylaws.html).
Technical specifications for stations, Analysis Centers and
Data Centers are included in the Call for Participation.
The Committee will develop operational guidelines for
incorporating the TGBM monitoring into the IGS. Links to
the International Association of Geodesy (IAG), the
International Association for the Physical Sciences of the
Ocean (IAPSO), the Global Sea Level Observing System
(GLOSS), the Permanent Service for Mean Seal Level (PSMSL),
the European Sea Level Service (ESEAS), the APSG Seal Level
Working Group, NOAA/NOS and other international and
national agencies will be incorporated, as appropriate.
* Call for Participation
The TIGA Pilot Project Committee is seeking participation
in the following categories:
- TIGA Observing Stations
- TIGA Data Centers
- TIGA Analysis Centers
- TIGA Associate Analysis Centers
In addition a Call is issued for a search for historical
GPS and tide gauge data.
# TIGA Observing Stations
The Call goes to individual stations and organizations
operating GPS-equipped tide gauge stations or GPS receivers
near tide gauge stations. Stations not belonging to the IGS
network are also welcome to answer this Call. However, only
stations which maintain an open data policy for both GPS
and TG data can participate. Observing stations which can
provide support in the categories: satellite altimetry
calibration, long-term sea level trend analysis, and global
isostatic adjustment / uplift studies are asked to
participate. Participating stations should have been in
operation for several years for both GPS and tide gauges or
the long-term deployment of a GPS-equipped tide gauge
system should be under way.
GPS sites participating in the TIGA-PP will have to observe
the same guidelines and rules as official IGS sites, except
the rules for data upload and timeliness. At
(http://igscb.jpl.nasa.gov/guide_igs.html) and
(http://igscb.jpl.nasa.gov/join_igs.html) the guidelines
can be found..
The primary goal of TIGA is to provide height coordinates
and velocities of the vertical motion of the participating
CGPS @ TG stations, but with much higher latency. This Call
specifically targets on areas with uneven geographical
distribution of GPS-equipped tide gauge systems, most
notably due to the lack of communications or stations in
coastal areas of Africa, Asia, China, India, Russia,
Southeast Asia, South America and the polar regions.
Regular service of the TIGA Analysis Centers will have a
latency of one year. GPS data are accepted at any date
before. To address as many as possible science
applications, storage of hourly data for the tide gauges is
necessary. For sea level studies additional information
about, e.g., air pressure and temperature, wind speed,
direction or gust are desirable. Station owners are
encouraged to provide these parameters together with the
tide gauge data.
Local ties between the GPS antenna reference point and
collocated instrumentation (e.g. DORIS, SLR, VLBI, gravity
sites) should be known within an accuracy of about 1mm for
the height component. In order to maintain the long-term
stability, all TGMB's and additional BM's, including the
GARP, should be re-leveled by a first order leveling on a
routine basis. The repetition period depends on the local
geographical/geological situation. For leveling between the
TGBM and the TG within the frame of the TIGA-PP,
responsibility shall be assumed by the TG
owner/hydrographic office and efforts will be made to
assess the accuracy of data. TG owner participate by
providing the needed information and committing themselves
to perform the leveling. Copies of the leveling log sheets
and sketch maps should be send to TIGA Data Centers as
well. A contact person should be identified in the
Proposal.
TIGA Observing Station operators have the responsibility to
coordinate their activities fully with the appropriate
corresponding national tide gauge data authorities with
regard to the provision of tide gauge information to the
Pilot Project. A minimum requirement is the provision of
monthly mean sea level values to the PSMSL. In addition, in
accord with the requirements of the GLOSS Implementation
Plan, hourly (or similar) 'delayed mode' raw tide gauge
data must be made available, as soon as possible and free
of charge, to one of the GLOSS centers (i.e. either the
PSMSL itself, or to the University of Hawaii Sea Level
Center (UHSLC) or to the Australian National Tidal Facility
(NTF)), from where it will be provided to the TIGA-PP. In
the case that such data cannot be made freely in this way,
there should be explanation of the national tide gauge data
policy and of any other factor which inhibits ready
provision of the data. (Authorities which in addition are
capable of providing data in 'fast mode', e.g. for the use
of radar altimeter calibration, may send their data to the
GLOSS Fast Data Center at UHSLC.)
# TIGA Data Centers
The Pilot Project will support other research activities
incorporating tide gauge data. A prerequisite is the
storage of additional metadata, e.g. repeated local ties
between the GARP and the primary TGBM, as well as between
all additional TGMB's. All archived data should be
available by anonymous FTP for GPS data and (at least) as
hardcopies for metadata.
Data Centers are solicited to fulfill three functions:
1. Store GPS data sent by different media (FTP, computer
tapes, CD-ROM, diskettes, etc.) with high and changing
latency.
2. Store Metadata (e.g. leveling data, sketch maps of the
TG) of any kind (e.g. computerized, handwritten,
microfiches, etc.)
3. Establish links to Tide Gauge Data Centers for easy
and convenient data access.
Repositories of tide gauge data for stations participating
in the Pilot Project are in the sole responsibility of the
appropriate national or international data centers, e.g.
PSMSL, UHSLC, or NTF. TIGA Data Centers will not store or
duplicate tide gauge data.
# TIGA Analysis Centers (TAC)
Analysis Centers will process tracking data of the CGPS @
TG network in order to calculate and make available station
coordinates with special emphasis on the height component
and rates of their vertical motions. All TAC's will include
a common subset of IGS permanent stations for a common
reference frame. To achieve a homogeneous spatial network,
they will also agree upon the inclusion of non-CGPS @ TG
stations. TAC's will follow recommendations given in the
IERS Standards as far as possible.
Refer to
(ftp://igscb.jpl.nasa.gov/igscb/resource/accharter.txt) for
a general charter on establishing an AC.
Three types of TAC's are defined in this Call for
Participation. Type I centers are preferred.
+ Type I TAC's will re-compute a selected subset of the
IGS network data (including a retro-processing of IGS
station data for CGPS @ TG) for improved long-term
stability of the reference frame since the inception of
the IGS and process current and future data with a
latency of at least one year.
+ Type II TAC's will process current and future data with a
latency of at least one year
+ Type III TAC's will process data with reduced latency
in order to support operational activities that cannot
tolerate large processing delays.
A combination of the above is of course acceptable.
Moreover, TIGA AC's are encouraged to study the vertical
accuracy of the GPS coordinates and to provide advice on
their improvement. Studies of the tropospheric effects on
the height determination, ocean loading and reference frame
issues may also be worked out.
# TIGA Associate Analysis Centers (TAAC)
The TIGA-PP is seeking groups to perform independent
routine analyses and evaluations of the vertical motion
rates including:
- Comparisons of results obtained by the TAC's similar to
those routinely performed by the IGS
- Evaluations based on independent techniques, e.g.,
DORIS, SLR, VLBI, and absolute gravity observations.
Proposals from those groups are encouraged.
- TAAC's should explore and assess potential improvement
of the suite of IGS classical and other products, e.g.,
PWV or vertical motions.
- TAAC's should provide general contributions to improve
the processing strategy, and provide an independent but
critical review.
Refer to
(ftp://igscb.jpl.nasa.gov/igscb/resource/accharter.txt) for
a general charter on establishing an AAC.
# Survey for historical GPS and tide gauge data
With TIGA-PP also CGPS @ TG stations can be (re)-processed,
which where not available before due to latency or other
reasons. This Call will encourage station owners to provide
their archived GPS and tide gauge data to the TIGA Data
Centers and Tide Gauge Data Centers. The only requirement
is to observe the same guidelines such as TIGA Observing
Stations. A Letter of Intent should be submitted.
* LETTER OF INTENT
Those organizations interested in submitting a proposal in
response to this Call for Participation should send a one-
page non-binding Letter of Intent due by August 1, 2001.
The Letter of Intent should state that you intend to submit
a proposal. The letter should be sent to the IGS Central
Bureau with a copy to the chair of the TIGA-PP:
Ruth Neilan, Director
IGS Central Bureau
Jet Propulsion Laboratory
M/S 238-540
4800 Oak Grove Drive
Pasadena, CA 91109 USA
Telephone Number: (818) 354-8330
Fax Number: (818) 393-6686
Email: igscb at igscb.jpl.nasa.gov
Tilo Schoene
GeoForschungsZentrum Potsdam (GFZ)
c/o DLR Oberpfaffenhofen
82234 Wessling
Telephone Number: +49-8153-281391
Fax Number: +49-8153-281207
Email: tschoene at gfz-potsdam.de
The letter should include the following information:
- Organization name and address
- Name, address, and telephone and fax numbers of the
principal point of contact
- Specific areas of support which will be addressed in
the proposal.
Letters of Intent must be received on or before July 1,
2001. Material in these letters is for information purposes
only and is not binding on the signatories. Those
organizations responding will receive additional
documentation and information in the future.
* GENERAL PROPOSAL INFORMATION
Proposals submitted in response to the Call for
Participation must include specific details on the
technical support that will be offered by the organization
and a management plan. These two main proposal sections
will be used for proposal evaluation and to facilitate
comparative analysis. Proposals must be signed by an
official authorized to certify institutional support,
sponsorship and management of the proposed activities.
Proposals are due on or before August 1, 2001, at the
addresses provided above. To start with the Pilot Project
activities and the coordination of the Project a very
stringent schedule is set. Due to the importance of the
project, groups may join at any time afterwards during the
time of the Pilot Project. However, a Letter of Intent will
be necessary for groups willing to join later.
* PROPOSAL EVALUATION AND SELECTION
The principal criteria considered in evaluating the
proposal are their relevance to the IGS and TIGA-PP
objectives, their intrinsic merit, and overall contribution
to the service when compared to contributions available
through other proposals. In addition to these criteria,
management factors will be considered in the selection.
If the TIGA-PP decides to accept only a portion of the
proposal, the submitting organization will be given the
opportunity to accept or decline such partial acceptance.
Organizations responding to this Call for Participation
will be notified by the Chairman of the Pilot Project
committee of the outcome of the proposal selection process
in September 2001.
* SCHEDULE OF IGS TIGA ACTIVITY
July 1, 2001 Letters of Intent due
August 1, 2001 Proposals due
August/September Evaluation/Selection
September 2001 Responses and Letters of Acceptance
sent after the IAG General Assembly
(Sep 3-7, 2001)
* PROPOSAL PREPARATION DETAILS
The Proposal should be structured as follows:
- Cover Page (details below)
- Proposal Summary
- Description of Proposed Activities
- Management Proposal
- Financial Arrangements.
The Cover Page should contain the following information:
- IGS TIGA component referred to
- parent/funding organization
- name and title of authorizing official
- name and title of primary point of contact
- mailing address
- phone/fax/email
- cooperating organizations/institutes
- signatures (the cover page should be signed both by the
Authorizing Official committing the
organization/institution to the IGS activity and the
primary point of contact involved).
Please send your proposal via postal mail to the IGS
Central Bureau at the above address. For easier
distribution to the reviewers, an additional e-mail version
should be made available (in ASCII or attached Word file).
Please send the email version to igscb at igscb.jpl.nasa.gov and
tschoene at gfz-potsdam.de.
Proposals should not exceed 15 pages.
--
Tilo Schoene
GeoForschungsZentrum Potsdam (GFZ), Division 1, Section 1.2
c/o DLR Oberpfaffenhofen, D-82234 Wessling, Germany
mailto:tschoene at gfz-potsdam.de Tel: +49-(0)8153-28 1391
http://op.gfz-potsdam.de/ Fax: +49-(0)8153-28 1207
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