Global Sea Level Observing System (GLOSS)Mark Merrifield (Chair of GLOSS GE)Thorkild Aarup (IOC)OOPC 2-4 May 2007
The GLOSS Programme • Established by IOC in 1984 with the aim of improving the quantity and quality of sea level data to international sea level data centres. • Primary element of GLOSS is the GLOSS Core Network (GCN) of approximately 300 sea level stations in nearly 90 countries. • GCN designed to provide high quality sea level data for application to climate, oceanographic, coastal research (Examples WOCE, CLIVAR, GODAE, GOOS,..). • GLOSS recommends GCN stations report high frequency data in near real time in support of operational modelling, tsunami and storm surge warnings and altimeter calibration.
GLOSS DATA STREAMS • Delayed mode, quality controlled Mean Sea Level (MSL) data to the PSMSL (Liverpool, UK) • Delayed mode, quality controlled higher-frequency data (e.g. hourly heights) to a GLOSS Data Centre (PSMSL or UHSLC) • Real time/Fast data to GLOSS Fast Centre at UHSLC and where relevant international tsunami warning centers • GPS data to IGS/TIGA Centre (Potsdam, Germany) initiated in 2001.
Status of GCN • Presently 168 stations (58%) reporting HF data in real time or fast mode (within ~ 1 month) • Some 34 stations are expected to be upgraded to real time or fast or replaced with nearby operational stations in 2007-2008 bringing the total of operational stations to 202 (70% of GCN) • ~ 90 stations are not delivering high frequency/real time or fast data • ~ 30% national restrictions concerning exchange of HF data • ~ 30% lack infrastructure and/or technical capability to install gauges • Remaining stations need some form of equipment upgrades (i.e. modern water level gauges and/or DCPs/satellite transmitters). • ~ 80* stations in GCN have GPS or DORIS stations nearby