| Date: | 2001-06-07 08:28:00 | |
| Sender: | Tilo Schoene, GFZ Potsdam <Tilo Schoene <tschoene@gfz-potsdam.de>> | |
| Subject: | [SLR-Mail] No. 776: GPS Tide Gauge Benchmark Monitoring Pilot Project / Call for Participation | |
| Author: | Tilo Schoene, GFZ Potsdam | |
| Content: | ******************************************************************************** SLR Electronic Mail 2001-06-07 08:28:00 UTC Message No. 776 ******************************************************************************** Author: Tilo Schoene, GFZ Potsdam Subject: GPS Tide Gauge Benchmark Monitoring Pilot Project / Call for Participation 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@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@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@igscb.jpl.nasa.gov and tschoene@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@gfz-potsdam.de Tel: +49-(0)8153-28 1391 http://op.gfz-potsdam.de/ Fax: +49-(0)8153-28 1207 From: Tilo Schoene ******************************************************************************** |