Please complete the protocol for Session 5 "Discussion and Summary".
Date
Introduction
- Hartmut: need to resolve do: RS define the frame, or all absolute (including Field)? Let’s spend 30 minutes
- Next steps? Graham Appleby will present on parallels with ILRS/laser ranging
- Let’s discuss publication and outlook for a governing board
Which Stations Realize the Frame?
- Vojtech: Single epoch stations
- Derek : single epochs are “nodes” of the frame that may “decay” over time
- Vojtech: start by assessing traceability multi-epoch stations and instruments. Categorize stations by history, stability.
- Frame defined physically by a benchmark and its traceable gravity value
- Reference ITGRF stations: either characterized by (traceable) AG and a reference function or multiple AG measurements, etc. A reference station should be able to provide the current gravity value and uncertainty along with the linking/trace information.
- Single/multiple epoch stations whose uncertainty needs to include the (initially unknown) site stability.
- Derek: need to assess the current inventory to start the ITGRF and also mechanism to enlarge the ITGRF with new instruments and sites
- Hartmut: we need to users to be able to access the ITGRF in spite of the sparseness of AGs, etc.
- Discussion of what “realizes” the system and the frame?
- Frame is realized through absolute gravity measurements that are traceable either via comparisons and/or reference functions.
- Access to the frame via traceable observations including field stations, AG observations.
- Tradeable measurements are the realization of the system and the benchmark gravity value provides access to the frame
- Discussion of ITGRF Operation
- Graham to present on parallels with laser ranging ILRS governing board
- Nonhomogeneous distribution of stations
- Observations stations, center, data centers, analysis centers, a central bureau, a governing board. “Components required to achieve the goals of the service”
- Governing board is outward facing component (e.g. to IAG)
- Analysis standing committee ensure consistent quality across analysis centers
- Network engineering ensures instrument consistency and quality
- Graham recommends to start with a governing board (GB)
- George Vergios: instead of a service, recommends “coordination center” approach
- Graham to present on parallels with laser ranging ILRS governing board
- Hartmut: let’s initiate a core group structure today
- Propose to have the ITGRF “Coordination Group” (CG) under the BGI
- Four representatives/responsibilities
- Comparisons and traceability
- Reference Stations and Regional Coordinators. One on the CG
- Database / dissemination. Tolouse AGrav
- Analysis and processing of gravity. Time series analysis, links to IGETS. Building up reference functions, etc.
- Chairperson: general administration, outreach, papers, resolution, etc.
- BGI will renew its GB soon, good time to add ITGRF representation
- Derek: what tasks will this new group be responsible for?
- Ezequiel/Sylvain: we need an immediate roadmap and strategy. Guidelines, list of attributes, future structure, paper and resolution…
- Need to reach out for more regional participation: Middle East, Africa, SE Asis/Pacific, Australia, India
- CG Volunteer list;
- Hartmut Wziontek (Europe) – Chairperson
- Sylvain Bonvalot (Europe) – Co-chairperson (database)
- Derek van Westrum (North America) – reference station coordination
- Vojtech Palinkas (Europe) – traceability and comparisons
- To Be Determined - analysis and processing. Sylvain: possibly depends on AGrav attributes and future capabilities.
- Immediate Steps
- IUGG Resolution
- Current status and publication
- Find out what requirements for IUGG. Prefer to have a paper (white, peer?) at least submitted by the time the IUGG proposal process starts
- Paper contributors: Hartmut, Derek, Vojtech, Sylvain. Outline of paper mirrors the outline of this JWG meeting.
- All materials from this week will be on the BKG wiki.
- Next meeting: EGU session proposal (Marvin Reich). Early May 2027.
- Previous sessions in 2018 and 2019.
- Splinter meeting in 2027. Probably no remote participation
- Next online JWG meeting: Possibly the week of 30 November (week 49)