Transcript GLOSS (and MedGLOSS, GCOS etc.)

GLOSS (and MedGLOSS, GCOS etc.)
Philip L. Woodworth
Permanent Service for Mean Sea Level
Ostende GLOSS Course 2006
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
Altimeter System
Tide Gauge (float)
Bottom Pressure
Gauge
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,
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’.
GLOSS - The Global Sea Level
Observing System
Further Information
GLOSS Technical Secretary
Intergovernmental Oceanographic
Commission (IOC), UNESCO
email: [email protected]
Permanent Service for Mean Sea Level
Proudman Oceanographic Laboratory
email: [email protected]
http://www.pol.ac.uk/psmsl/programmes/gloss.info.html