TY - JOUR

T1 - Combining atmospheric and non-tidal ocean loading effects to correct high precision gravity time-series

AU - Antokoletz, E. D.

AU - Wziontek, H.

AU - Dobslaw, H.

AU - Balidakis, K.

AU - Klügel, T.

AU - Oreiro, F. A.

AU - Tocho, C. N.

N1 - 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 Río 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.

PY - 2024/1

Y1 - 2024/1

N2 - 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.

AB - 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.

KW - Geodetic instrumentation

KW - Loading of the Earth

KW - Time variable gravity

UR - http://www.scopus.com/inward/record.url?scp=85177789728&partnerID=8YFLogxK

U2 - 10.1093/gji/ggad371

DO - 10.1093/gji/ggad371

M3 - Article

AN - SCOPUS:85177789728

VL - 236

SP - 88

EP - 98

JO - Geophysical journal international

JF - Geophysical journal international

SN - 0956-540X

IS - 1

ER -