ICSM Geodesy Technical Subcommittee
This presentation is the property of its rightful owner.
Sponsored Links
1 / 17

ICSM Geodesy Technical Subcommittee Darwin 2nd September 2004 Bill Mitchell Manager PowerPoint PPT Presentation


  • 54 Views
  • Uploaded on
  • Presentation posted in: General

ICSM Geodesy Technical Subcommittee Darwin 2nd September 2004 Bill Mitchell Manager National Tidal Centre Bureau of Meteorology. Relative sea level trends (mm/year) for gauges with records longer than 20 years on the University of Hawaii Sea Level Centre archive. +1.13. +0.37. +2.79.

Download Presentation

ICSM Geodesy Technical Subcommittee Darwin 2nd September 2004 Bill Mitchell Manager

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

ICSM Geodesy Technical Subcommittee

Darwin 2nd September 2004

Bill Mitchell

Manager

National Tidal Centre

Bureau of Meteorology


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

Relative sea level trends (mm/year) for gauges with records longer than 20 years on the University of Hawaii Sea Level Centre archive

+1.13

+0.37

+2.79

-0.2

+0.42

-0.68

+0.26

+0.64

+1.79

-2.24

-2.03

+0.89

-2.21

+1.43

+3.80

+3.99

Average relative sea level trend is +0.63 mm/year

Regional coherency?


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

Instrumentation


South pacific sea level and climate monitoring project

South Pacific Sea Level and Climate Monitoring Project

National Tidal Centre

Bureau of Meteorology


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

National Tidal Centre

Bureau of Meteorology


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

+5.9

+9.0

+4.7

+7.5

+6.8

+10.9

+5.5

+11.7

+13.4

+5.1

+6.3

+13.5

+5.4

+4.1

+1.4

+12.3

+4.0

+5.7

+10.3

+5.2

+7.4

+6.7

+3.2

+3.7

+3.9

Relative rates of sea level change (mm/year). All are positive with the highest rates in the Northwest of Australia

National Tidal Centre

Bureau of Meteorology


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

+0.3

+1.5

+0.6

+0.5

-0.1

+0.6

+0.5

+0.2

-0.4

+0.2

+1.7

+1.1

+0.9

+1.2

+0.1

+0.8

+0.7

+0.8

+0.9

+2.5

+1.2

+0.8

+0.2

+1.0

-0.2

Contribution of atmospheric pressure to relative sea level rise rates (mm/year)

National Tidal Centre

Bureau of Meteorology


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

+0.5

+0.2

-0.1

0.0

+0.4

0.0

+1.2

-0.3

-0.2

-0.9

0.0

Contribution of change of vertical datum to rate of

sealevel rise (mm/year)


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

+5.1

+7.3

+4.2

+7.0

+6.5

+10.3

+5.0

+11.5

+13.8

+3.7

+4.9

+12.4

+4.5

+3.1

+2.2

+11.5

+3.3

+4.9

+9.4

+5.9

+2.7

+6.2

+3.0

+2.7

+4.1

Net rates of relative sea level rise (mm/year) as at 15th April 2004

National Tidal Centre

Bureau of Meteorology


Sea level and climate monitoring project

Sea Level and Climate Monitoring Project

Conclusions

On average, global relative mean sea levels have risen between 1 and 2 mm/year over the last century and there has not been a detectable acceleration in the last 50 years

Rates of relative sea level rise may vary considerably between sites due to site specific influences such as meteorology, oceanography and vertical tide gauge movement and land motion

The arrays are continuing to deliver long term, high quality datasets to the region and is thus satisfying their key objectives

National Tidal Centre

Bureau of Meteorology


Sea level and climate monitoring project1

Sea Level and Climate Monitoring Project

Conclusions (continued)

In order to derive stable estimates of relative sea level trends we must monitor for at least twenty years

An integral component of the operation of a tide gauge is accurate surveying between the gauge and the benchmarks in the vicinity

Changes in atmospheric pressure need to be monitored since they may significantly contribute to trends in sea level

National Tidal Centre

Bureau of Meteorology


South pacific sea level and climate monitoring project1

South Pacific Sea Level and Climate Monitoring Project

Conclusions (continued)

Accurate monitoring of the geological motion of islands is necessary to adjust the trends - can use CGPS

Note: beware of short-term datasets!

National Tidal Centre

Bureau of Meteorology


Icsm geodesy technical subcommittee darwin 2nd september 2004 bill mitchell manager

86 years of tide gauge records at Fort Denison in Sydney Harbour

show a trend of 0.9 mm/year and the monthly minima are rising

faster than the monthly maxima


South pacific sea level and climate monitoring project2

South Pacific Sea Level and Climate Monitoring Project

Future

Within three years a major refurbishment of the Australian Baseline Array

Potential for installation of CGPS at each site as part of the refurbishment

Will need to precise level between CGPS and Baseline station

National Tidal Centre

Bureau of Meteorology


  • Login