The relationship between the accuracy of gravity tide measurements and ocean weather

Dynamics of oceans and seas can be monitored through the Internet nearly real time, so we correlated visually the noise of the recorded gravity tide with the available marine data - wave height and direction maps - (www.oceanweather.com) with the help of a picture sequence.

Gravity tide signal registered with 2 min. sampling rate in the Geodynamical Observatory of the GGRI of HAS has an average noise level of about +/- 2 microGal standard deviation. Disregarding the transient phenomena, which are connected to the seismic activity directly, the noise of the measurements grows sometimes significantly and the standard deviation of the signal may attain the +/- (5-10) microGal value. The reason of the increased background noise is primarily the heavy swell in the North Atlantic areas. Dynamics of oceans and seas can be monitored through the Internet nearly real time, so we correlated visually the noise of the recorded gravity tide with the available marine data - wave height and direction maps - (www.oceanweather.com) with the help of a picture sequence.

From this it can be seen, that certain marine processes ongoing many thousands of kilometres far from Sopron (Hungary) have a really adverse effect on the accuracy of the gravity measurements and it is important to monitor these processes continuously. When the noise level is high it is not advised to carry out measurements or the measurements referring to these time periods cannot be used for investigations requiring high accuracy (< 5 microGal).