G. Jentzsch et al., Ocean tidal loading affecting precise geodetic observations on Greenland: Error account of surface deformations by tidal gravity measurements, PHYS CH P A, 25(4), 2000, pp. 401-407
Citations number
24
Categorie Soggetti
Earth Sciences
Journal title
PHYSICS AND CHEMISTRY OF THE EARTH PART A-SOLID EARTH AND GEODESY
Air-borne and satellite based altimetry are used to monitor the Greenland i
ce-cap. Since these measurements are related to fiducial sites at the coast
, the robustness of the height differences depends on the stability of thes
e reference points. To benefit from the accuracy of these methods on the ce
ntimeter level, station corrections regarding the Earth tides and the ocean
tidal loading have to be applied. Models for global corrections esp. for t
he body tides are available and sufficient, but local corrections regarding
the effect of the adjacent shelf area still have to be inferred from addit
ional observations. Near the coast ocean tidal loading causes additional ve
rtical deformations in the order of 1 to 10 cm Therefore, tidal gravity mea
surements were carried out at four fiducial sites around Greenland in order
to provide corrections for the kinematic part of the coordinates of these
sites. Starting in 1993 four stations were occupied on Greenland for a one
year record each.
The results show the expected strong tidal anomalies due to ocean tidal loa
ding. The loading computations confirmed these observations, but it turned
out that with global models only about 50 % of the observed effect can be e
xplained. This means that at these stations st vertical deformation of up t
o +/-3.5 cm is not corrected applying these global models. (C) 2000 Elsevie
r Science Ltd. All rights reserved.