A Trans-Siberian Tidal Gravity Profile (TSP) for the validation of the ocean tides loading corrections

Abstract

Tidal gravity observations have been performed across Siberia, along a profile extending from Novosibirsk to the West until Sakhalin Island to the East. All the stations were occupied by the same instrument (LCR402) for periods ranging from one to more than 2 years. The first goal was to compare the observed tidal parameters of the main tidal waves O1, K1 and M2 with modelled ones computed from nine different ocean tides models: SCW80, ORI96, CSR3, FES95, FES02, CSR4, GOT00, NAO99 and TPX06. In order to assess the overall accuracy of tidal predictions across Siberia, we selected also the best ocean tides models for long period tides, on the basis of previous comparisons. The observed amplitude factors and phase differences agree with the modelled ones within the associated RMS errors, generally at the level of 0.3%. On the other hand, the predicted tidal factors, computed from different ocean tides models, exhibit a high level of consistency (0.15%) on the Siberian territory. The tidal load vectors agree within 1 nm s−2. A mean of the different load vectors will provide the most precise corrections, except in the area of the Sakhalin Island, where the most recent models fit better the observations. The final conclusion is that gravity tides predictions, based on the mean of the most recent ocean tides models, have a precision of the order of 5 nm s−2 on the Siberian territory.