Identifying common hydrological signals observed by superconducting gravimeters

Abstract:

Superconducting gravimeters have been deployed at numerous observatories around the world especially for geodetic and geophysical purposes. Thanks to their high sensitivity to mass transport of any form and a sufficient temporal resolution, these instruments are increasingly used in hydrological studies including inter-comparisons with global hydrological models and GRACE products. However, the contribution of the local zone significantly exceeds the remaining regional and global effects that are essential for such inter-comparisons. Nevertheless, intense large scale hydrological phenomena propagate into local variations and, therefore, are observable by gravimeters hundreds of kilometres apart.

In this study, we analyse time series of a selected group of superconducting gravimeters in Europe with a focus on common features related to large scale hydrological variations. The common signals are inferred using combination of various global hydrological models, in-situ hydro-meteorological observations and gravity time series corrected for non-hydrological effects. A special emphasis is put on extreme non-periodic variations. In this regard, we investigate the benefits of superconducting gravimeters in terms of their use for deriving drought and floods indices, over traditional hydrological observation techniques and global models that are utilized for individual hydrological compartments rather than total water storage variations. In addition, we discuss the detectability of identified large scale hydrological variations by GRACE.