Workshop on the State of GPS Vertical Positioning Precision: Separation of Earth Processes by Space Geodesy Sponsored by the European Center for Geodynamics and Seismology (ECGS), the Fonds National de la Recherch (Luxembourg), the Natural History Museum of Luxembourg, and UNAVCO Scientific Committee: G. Blewitt K. Larson T. van Dam O. Francis P. Elosequi Venue: Luxembourg City, Luxembourg at the hotel Parc-Bell-Vue Reservations to be made by Patricia Codran ECGS (mailto:pc@ecgs.lu) Date: 2-4 April, 2003 (week before EGS) Registration Fee: 50 euros. Registration limited to 50 participants!!! ABSTRACT: Observed signals in GPS data are the sum of noise and real crustal motions. Interpretation of the data depends on our ability to extract a signal of interest from the total signal. This workshop will highlight the difficulties associated with extracting a signal such as post-glacial rebound, plate tectonics or loading, from vertical geodetic data. FORMAT: Session Chairs will be asked to invite appropriate papers, to coordinate contributed papers in their session, and to coordinate written proceedings, including a paper which summarizes useful outcomes from the discussions. In the spirit of a true workshop, presentations may be as short as a single figure or a brief introductory statement, followed by discussion. The Session Chairs may wish to start each session with one review type of paper to provide a context for the session; however, AGU-EGS types of "complete" presentations with little opportunity for open discussion are discouraged. The Session Chairs should provide a (partial) list of discussion topics in advance of the meeting to give all workshop participants an opportunity to prepare and contribute some material for discussion. Morning Sessions: Oral Invited Speakers, Pertinent Contributed Speakers Afternoon Sessions: Oral/Posters Publication Proceedings: 'Cahiers du Centre Europen de Godynamique et de Sismologie' (Luxembourg Funding Requirement) General layout of the meeting, including suggested areas of discussion: DAY 1 Theme: Empirical Characteristics of GPS Vertical Data - Empirical measures over different spatial and temporal scales - Empirical measures in the wavelength and frequency domains - Effect of frame and coordinate realization methods on time series. - Effect of processing models and strategies on time series. - What "appears" to be signal, and what "appears" to be noise? - What characteristics appear to be limit the signal to noise ratio? - What is unexplained, surprising, or interesting? DAY 2 Theme: Performance and Limitations of Models - What are the limitations of GPS processing models and software? - How well do displacement models explain observed characteristics? - Which processing strategies minimize observed-modeled vertical? - What are the limitations of current vertical displacement models? - Vertical displacement models: observation or coordinate level? - What are the limitations of reference frames and realization? DAY 3 Theme: Resolutions - What should we do? - What do we recommend for processing models, strategies, frames? - What do we recommend for vertical displacement models? - What future research might improve vertical data quality? - How can errors be better characterized/quantified/understood? - How might we improve models of vertical displacements? For more information please see www.ecgs.lu or e-mail T. van Dam (tonie@ecgs.lu)