The need for high quality sustained sea level observations in a changing climate

1. The need for high quality sustained sea
level observations in a changing climate
ANGELA HIBBERT, ELIZABETH BRADSHAW
NATIONAL OCEANOGRAPHY CENTRE, LIVERPOOL

2. Intergovernmental Panel on Climate Change Reports
• 1901-2010 Global Mean Sea Level rose by 1.7 mm/y, accelerating to
~3.2 mm/y in recent years.
• Use a compilation of paleo, tide gauge and altimeter data, plus model
scenarios
The need for high quality sustained sea level observations
in a changing climate

3. Monitoring UK Sea Level and Climate
Met Office State of the UK Climate Annual Report
UK sea level index computed from five tide gauges
stations (Aberdeen, North Shields, Sheerness,
Newlyn and Liverpool).
The uncertainties are as large now as they were in
the 1900s.

4. Status of the UK Tide Gauge Network
Deterioration in the quality and availability of data over last decade
Serious implications for UK sea level research, advice given to
policymakers, ability to forecast and mitigate sea level variability, including
tides, extremes and longer-term trends.
Technology last upgraded ~early 1990's. Now does not comply with
international recommendations.

5. Long term trends – longest record in wales
At least 60 years of high data are needed to evaluate long-term sea level change.
Only Holyhead has a record of >=60 years.
MonthlyMeanSeaLevel(mm)
Month/Year

6. Issues with long term trends - Barmouth
• January 2013: Sensors damaged in storm
• May 2016: New bubbler sensors installed
but issues with levelling data
• 2013-2018: No Mean Sea Level data
produced

7. High Frequency data – meteotsunami/storm
surges/seiches
• Observations at ~1min intervals are essential to examine storm surges or
meteotsunamis
Woodcut image of the flooding caused by the 1607 storm
surge in the Bristol Channel.
Printed in London by W. I. for Edward White.
South West UK meteotsunami
Oscillations ~20cm above predicted

8. Vertical Land Movement at tide gauges
Prof. Richard Peltier's Glacial Isostatic Adjustment
prediction for tide gauge rates

9. Newport tide gauge trend
Cardiff
GPS station
Monthly Mean
Sea Level

10. None of these are co-located <500m from the tide gauge. International guidance states "A
GNSS antenna should be mounted as close as possible to the tide gauge, or even fixed to
it if the installation allows."
Data from Système d’Observation du Niveau des Eaux Littorales (SONEL)
Global Navigation Satellite System (GNSS)
data at tide gauge stations

11. Futureproofing the UK Tide Gauge Network
• New radar technology with secondary sensors for resilience
• GNSS for land level and sea level monitoring
• High frequency sampling for tsunami monitoring
• Data transmission via free satellite systems
• Powered by renewable energy

12. With better data, we can improve our understanding of climate change
and mitigation of coastal hazards through informed decision-making.
The National Oceanography Centre has a long history of developing and
installing sea level measurement equipment for these purposes and
urges Policymakers to take rapid action to improve the standard of sea
level monitoring equipment in Wales.
Take Home Message:
Porthcawl 2008. Credit: David Jones/PA Wire