Non-tidal ocean loading signals of the North and Baltic Sea from
terrestrial gravimetry, GNSS, and high-resolution modeling
Abstract
Non-tidal ocean loading signals are known to be a significant source of
geophysically induced noise in gravimetric and geodetic observations
also far-away from the coast and especially during extreme events such
as storm surges. Operational products suffer from a low temporal and
spatial resolution and reveal only small amplitudes on continental
stations. Dedicated high-resolution sea-level modelling of the North and
Baltic Sea provides a largely improved prediction of non-tidal ocean
loading signals. Superconducting gravimeter and GNSS observations on the
small offshore island of Heligoland in the North Sea are used for a
thorough evaluation of the model values revealing correlations of up to
0.9 and signal reductions of up to 50 % during a storm surge period of
one month in Jan-Feb 2022. Additional continental superconducting
gravimeter stations are used to assess the benefits from high-resolution
modelling for an improved signal separation further away from the coast.