|IOC group of experts on the Global Sea Level Observing System (GLOSS), eleventh session, Paris, France, 13-15 May 2009|
(2010). IOC group of experts on the Global Sea Level Observing System (GLOSS), eleventh session, Paris, France, 13-15 May 2009. GOOS Report, 181. JCOMM Meeting Report, 73. 26, V annexes pp.
Part of: GOOS Report. UNESCO, more
JCOMM Meeting Report. IOC/WMO: Paris, more
This report presents a summary of the topics discussed at the Eleventh Session of the Group of Experts on the Global Sea Level Observing System (GLOSS-GE). The Group of Experts evaluated the status of its GLOSS station networks. Regarding the GLOSS Core Network, it recognized the need for a clear policy on the meaning of "fast delivery" and to have the necessary capacity to handle fast-delivery data. The sub-networks of co-located and near-co-located GPS stations need to be improved and completed, including the infrastructure to ensure data processing and products. The Group of Experts accepted that all GPS stations should, if possible, be tied to the corresponding tide gauge benchmarks; it also stressed the importance of improving cooperation between the sea level and the geodetic communities and of relating the sea level station data to the TOPEX/Poseidon–Jason satellite data. It accepted the main conclusions and recommendations of the Workshop on Precision Observations of Vertical Land Motion at Tide Gauges (May 2009). The Group of Experts reviewed recent research based on tide gauge observations which is currently addressing the main factors determining mean sea level: thermal expansion; changes in glaciers, ice fields and ice caps; the considerable differences between the periods 1961–1993 and 1993–2003 are not easy to explain (to reduce the error requires a global data set, but there has been a decline in data submission, especially in the northern hemisphere, since about 1997). The Group addressed the question of whether and how to exploit tide gauge stations in the context of tsunami and other ocean hazards warning systems, particularly on a regional level. This may require expanding the field of expertise of GLOSS and revision of its own Terms of Reference. The Group of Experts examined the real-time station network and the work of the Sea Level Station Monitoring Facility, in Ostend (Belgium) and acknowledged the important service it provides to many sea level institutions without access to the GTS. The Group of Experts also recognized the Facility as the GLOSS designated centre for real time sea level data. The Group adopted the GLOSS Manual and Technical Report on Quality Control of Sea Level Data. It reviewed the sea level products now available on the World-Wide Web and updates on regional and national sea level activities were provided. The Group reviewed present links between GLOSS and other relevant programmes. It also received information on the latest technical developments regarding radar gauge intercomparison and BGAN- based tide gauges. The Group identified issues or actions to be addressed to its parent body, JCOMM, at its third session (November 2009) and drew up a list of its own intersessional activities for 2009–2011.