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Ostende GLOSS Course 2006 GLOSS (and MedGLOSS, GCOS etc.) Philip L. Woodworth Permanent Service for Mean Sea Level
Ostende GLOSS Course 2006
GLOSS (and MedGLOSS, GCOS etc.)
Philip L. Woodworth
Permanent Service for Mean Sea Level
GLOSS
The Global Sea Level Observing System
Also known as
“ Global Level of the Sea Surface”
GLOSS Objectives
• Establishment of high quality global and regional sea level
networks for application to climate, oceanographic and
coastal sea level research
• Sea level stations around the world for long term climate
change and oceanographic sea level monitoring
• Coordinated by the Intergovernmental Oceanographic
Commission (IOC)
• Major contributor to IOC’s Global Ocean Observing
System (GOOS)
Some History
• GLOSS was initiated in the 1980s with the aim of increasing the quantity and quality of month and annual MSL data to the Permanent Service for Mean Sea Level (PSMSL)
• A network, now called the GLOSS Core Network, was defined to which all countries would contribute
• These ideas formed the basis for the first GLOSS Implementation Plan
The GLOSS Core Network
More History
• By the 1990s there had been many technical developments in sea level measurement:
Satellite Altimetry
GPS for measuring land movements• The second GLOSS Implementation Plan was written
to define:
GLOSS Core Network
A sub-network for Long Term Trends
A sub-network for Altimeter Calibration
A sub-network for Ocean Circulation
Ways of Measuring Sea Level Changes
Tide Gauge (float)
Bottom Pressure Gauge
Altimeter System
Ways of Measuring Land Level Changes
GPS Absolute Gravity
More History continued
• Another important change was that tide gauge authorities were asked to provide their ‘higher frequency’ sea level data (e.g. hourly values or similar) in addition to MSL values to the PSMSL.
• Two GLOSS Date Centres defined in addition to PSMSL:
GLOSS Fast Centre at Hawaii (where ‘fast’ means data in a few weeks e.g. for altimeter calibration)
GLOSS Delayed Mode Centre alongside PSMSL
Real Time Data in 2000’s
• Most recently there has been a request for as much GLOSS data to be delivered in near real time:
1. Allows data to be provided to a new set of users e.g. tsunami people.
2. Allows faults to be identified and fixed earlier and so also better delayed-mode data eventually.
• GLOSS Fast Centre at Hawaii also defined to be the GLOSS Real Time Centre
GLOSS Status
GLOSS status can be measured by how well the network is providing data to data centres:
• MSL data available at PSMSL
• Real-time data available at Real-Time Centre
• Delayed-mode data available at Delayed-Mode Centre
GLOSS Real-time coverage 22 September 2006
GLOSS Activities
Regional Developments
• Regional networks of gauges with greater spatial density, to serve the particular oceanographic interests of those regions - examples: IOCARIBE (Caribbean), MedGLOSS (Mediterranean & Black Seas)
National Activities
• Contribution to the activities of national agencies by improving the standards for sea level recording around the world
Training
• Annual training courses on the techniques of tide gauge operations, and workshops on special interests e.g. measurements in environmentally hostile areas
Responsibilities of GLOSS Data Providers
There are 3 responsibilities of GLOSS data providers:
1. Monthly and annual MSL data to PSMSL by 6 months after the data-year
2. Delayed-mode higher-frequency data (typically hourly values), quality controlled to one of the GLOSS centres (in practice PSMSL again or UHSLC) 4 months after recording
3. ‘Fast’ H-F data (not quality controlled) to GLOSS Fast Centre at UHSLC
GLOSS Data Availability
Data from GLOSS tide gauges
• Permanent Service for Mean Sea Level http://www.pol.ac.uk/psmsl/
• University of Hawaii Sea Level Center http://www.soest.hawaii.edu/UHSLC/
Also Regional Centres
• MedGLOSS
GLOSS and GCOS
The Global Climate Observing System has defined a
set of approximately 180 tide gauges for long term
climate (sea level) monitoring
These can to a good approximation be considered the
same sites as the GLOSS Core Network
In a similar way as the IOTWS has major overlap with
the GLOSS Network in the Indian Ocean
Conclusion is that all networks have to be ‘multiple
use’.
http://www.pol.ac.uk/psmsl/programmes/gloss.info.html
GLOSS - The Global Sea Level Observing System
Further Information
GLOSS Technical Secretary Permanent Service for Mean Sea LevelIntergovernmental Oceanographic Proudman Oceanographic LaboratoryCommission (IOC), UNESCOemail: [email protected] email: [email protected]
