 |
| Titel |
Preliminary analysis of the connection between ocean dynamics and the noise of gravity tide observed at the Sopronbánfalva Geodynamical Observatory, Hungary |
| VerfasserIn |
G. Papp, E. Szűcs, L. Battha |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250060351
|
|
|
|
|
|
| Zusammenfassung |
| An experimental development of a PC controlled CCD ocular system applied for the LaCoste
and Romberg G949 gravimeter of the Geodetic and Geophysical Research Institute of the
Hung. Acad. Sci. made the continuous observation of time variation of gravity possible. The
system was operated for half a year in the Sopronbánfalva Geodynamical Observatory to test
its capabilities. The primary aim of this development was to provide an alternative and
self-manageable solution for the standard/factory CPI reading of this type of gravimeter and
use it for the monitoring of earth tide phenomenon. It, however, turned out that this system is
sensitive enough to observe the effect of variable seismic noise (microseisms) due to the
changes of ocean weather in the North Atlantic and North Sea regions at microGal level (1
μGal=10-8 m/s2). Up to now much attention was not paid to its influence on the quality and
accuracy of gravity observations because of the large distance (> 1000 km) between
the observation place (generally the Carpathian-Pannonian basin) and the source
locations (centers of storm zones of the northern hydrosphere). Based on an elementary
single wave surface deformation model the noise levels of gravity observations were
compared to the spectral characteristics of seismic time series recorded at the same
time in the Observatory. Although the sampling rate of gravity records was 120
s the daily variation of gravity noise level could be correlated to the variation of
spectral amplitude distribution of the analyzed high pass filtered (cut-off frequency =
0.005 Hz) seismograms in the frequency band between 0.005 Hz and 10 Hz. Also
available daily maps of ocean weather parameters were used to support both the
correlation analysis and the parametrization of the source of microseisms for further
statistical investigations. These maps which were processed by standard image
processing algorithms provide numerical data about geometrical (distance and azimuth of
the source relative to the observation point) and physical (mass of swelling water)
quantities. The information can be applied for characterizing the state of ocean
weather at a given day which may help the prediction of its influence in the future.
Probably it is the first attempt to analyse quantitatively the effect of ocean weather
on gravity observations in this specific area of the Carpathian-Pannonian region. |
|
|
|
|
|