Combining atmospheric and non-tidal ocean loading effects to correct high precision gravity time-series

authored by: E. D. Antokoletz, H. Wziontek, H. Dobslaw, K. Balidakis, T. Klügel, F. A. Oreiro, C. N. Tocho
Abstract: In modelling atmospheric loading effects for terrestrial gravimetry, state-of-the-art approaches take advantage of numerical weather models to account for the global 3-D distribution of air masses. Deformation effects are often computed assuming the Inverse Barometer (IB) hypothesis to be generally valid over the oceans. By a revision of the IB assumption and its consequences we show that although the seafloor is not deformed by atmospheric pressure changes, there exists a fraction of ocean mass that current modelling schemes are usually not accounting for. This causes an overestimation of the atmospheric attraction effect over oceans, even when the dynamic response of the ocean to atmospheric pressure and wind is accounted through dynamic ocean models. This signal can reach a root mean square variability of a few nm s-2, depending on the location of the station. We therefore test atmospheric and non-tidal ocean loading effects at five superconducting gravimeter (SG) stations, showing that a better representation of the residual gravity variations is found when Newtonian attraction effects due to the IB response of the ocean are correctly considered. A sliding window variance analysis shows that the main reduction takes place for periods between 5 and 10 d, even for stations far away from the oceans. Since periods of non-tidal ocean mass variability closely resemble atmospheric signals recorded by SGs, we recommend to directly incorporate both an ocean component together with the IB into services that provide weather-related corrections for terrestrial gravimetry.
External Organisation(s): Federal Agency for Cartography and Geodesy (BKG)
Universidad Nacional de La Plata
CONICET
Helmholtz Centre Potsdam - German Research Centre for Geosciences
Servicio de Hidrografía Naval (SHN)
Type: Article
Journal: Geophysical journal international
Volume: 236
Pages: 88-98
No. of pages: 11
ISSN: 0956-540X
Publication date: 01.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Geophysics, Geochemistry and Petrology
Electronic version(s): https://doi.org/10.1093/gji/ggad371 (Access: Open)

BibTeX

@article{6d7611a7513d48cb9457f483426e4fd3,
title = "Combining atmospheric and non-tidal ocean loading effects to correct high precision gravity time-series",
abstract = "In modelling atmospheric loading effects for terrestrial gravimetry, state-of-the-art approaches take advantage of numerical weather models to account for the global 3-D distribution of air masses. Deformation effects are often computed assuming the Inverse Barometer (IB) hypothesis to be generally valid over the oceans. By a revision of the IB assumption and its consequences we show that although the seafloor is not deformed by atmospheric pressure changes, there exists a fraction of ocean mass that current modelling schemes are usually not accounting for. This causes an overestimation of the atmospheric attraction effect over oceans, even when the dynamic response of the ocean to atmospheric pressure and wind is accounted through dynamic ocean models. This signal can reach a root mean square variability of a few nm s-2, depending on the location of the station. We therefore test atmospheric and non-tidal ocean loading effects at five superconducting gravimeter (SG) stations, showing that a better representation of the residual gravity variations is found when Newtonian attraction effects due to the IB response of the ocean are correctly considered. A sliding window variance analysis shows that the main reduction takes place for periods between 5 and 10 d, even for stations far away from the oceans. Since periods of non-tidal ocean mass variability closely resemble atmospheric signals recorded by SGs, we recommend to directly incorporate both an ocean component together with the IB into services that provide weather-related corrections for terrestrial gravimetry.",
keywords = "Geodetic instrumentation, Loading of the Earth, Time variable gravity",
author = "Antokoletz, {E. D.} and H. Wziontek and H. Dobslaw and K. Balidakis and T. Kl{\"u}gel and Oreiro, {F. A.} and Tocho, {C. N.}",
note = "Funding Information: The authors sincerely thank the editor, Prof Duncan Agnew, and the anonymous reviewers for their supportive comments and suggestions during the review process of this paper. The authors also acknowledge Michael Van Camp from the ROB for providing the gravity time-series for Membach station, IGETS for providing Level 3 data for station Yebes and all stations operators for the maintenance of the different SGs used in this study. KB is funded by the DFG via the Collaborative Research Cluster TerraQ (SFB 1464, project-ID 434617780). EA, HW, HD, TK and FO worked on the numerical modelling. EA and HW processed the time-series of SGs. HD and KB provided expertise on ocean and atmospheric data sets used in this study. FO provided the local non-tidal ocean loading effects for the estuary of the R{\'i}o de La Plata. EA, HW, HD and CT drafted and coordinated the work on the manuscript. All authors contributed on the final version of the manuscript. ",
year = "2024",
month = jan,
doi = "10.1093/gji/ggad371",
language = "English",
volume = "236",
pages = "88--98",
journal = "Geophysical journal international",
issn = "0956-540X",
publisher = "Oxford University Press",
number = "1",
}