To be an oral-presentation at
European Geophysical Society 1998, Nice 1998
Long term components of the sea level fluctuations in European seas
1Institute of Physical Geodesy;
Tecnical
University Darmstadt
Sea level fluctuations relative to a fixed point of the crust,
as obtained from tide gauge observations, are important for
coastal monitoring.
These fluctuations are the combined effect of sea level changes relative
to a given reference surface and of crustal movements.
The first component, which is due to global mass/volume change and to regional
changes in the oceanic and atmospheric circulations, is obtained
from altimetric observations, the second by computation of the
geocentric coordinates of the stations using positioning techniques.
We are interested in the long term sea level fluctuations.
We analyse the long term variations of the absolute sea level, measured
by the ERS-1, ERS-2 and Topex/Poseidon satellites, and of the relative
sea level, given by the tide gauge observations, and we compare and combine
locally both types of data.
We analyse the correlation of the sea surface heights variations with
the variations of other sea-surface and atmosphere parameters:
sea surface temperature, wind speed and sea wave heights obtained
by satellite observations,
air temperature and air pressure at tide gauge stations locations.
The analysis shows that combined satellite and tide gauge observations
are contributing to an accurate analysis of sea level variations.
A high coherency between some parameters of the sea-atmosphere
system is demonstrated. Periodical signals are found and
observations over longer intervals are necessary to give confidence to the
values estimated for the trends.
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