Time series of superconducting gravimeters and water storage variations from the global hydrology model WGHM

Abstract

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Gravity changes associated with variations in local land-water distributions: Observations and hydrological modeling at Isawa Fan, northern Japan

“…Imanishi et al (2006) reproduced land-water distribution effects observed at Matsushiro, central Japan, with an empirical tank model, assuming an instant gravity response to precipitation of −0.040 µgal/mm and a linear gravity recovery after precipitation of +3 × 10 −6 µgal/s. Wziontek et al (2009) explained a seasonal gravity change of ∼10 µgal peak-to-peak at superconducting gravity stations in Europe by attraction and loading effects attributable to global land-water distributions. Creutzfeldt et al (2010a, b) reproduced a non-tidal gravity change of ∼10 µgal in amplitude at Wettzell, Germany, by using spatial integrations of local water distributions observed with a lysimeter and borehole moisture meters.…”

A comparison of the gravity field over Central Europe from superconducting gravimeters, GRACE and global hydrological models, using EOF analysis

“…Once the larger signals (such as tides, atmospheric pressure and polar motion) are removed, SG residuals show a seasonal variation due mostly to soil moisture and groundwater, and this is dominated by sources close to the gravimeter, in the local zone, L (meaning within about 1 km of the station). The extent of this zone (also called the near‐zone, Wziontek et al. 2009b) depends on the topography and soil properties for each station.…”

On the noise characteristics of time series recorded with nearby located GPS receivers and superconducting gravity meters

“…Longuevergne et al 2009;Naujoks et al 2010or Creutzfeldt et al 2010. As it was previously emphasized hydrology-induced gravity variation is the only factor limiting the observations from SGs to be used for geodynamical purposes (Mikolaj et al 2015) as the contribution of hydrosphere is station-dependent (Wziontek et al 2009). …”

“…Wziontek et al (2009) have shown that the gravity time series at Bad Homburg reflects only the global effects (attraction and loading) of hydrological water content. They concluded that the environmental characteristics of this station require some careful measurements on the site in order to correctly quantify the local hydrological effects.…”

“…Large seasonal fluctuations have indeed been observed in the SG and GPS data series that are caused by seasonal fluctuations in the atmosphere, ocean, and ground water, but also by geo-mechanical effects such as soil consolidation and thermal expansion of the structure supporting the GPS antenna (Zerbini et al 2001;Romagnoli et al 2003;Richter et al 2004). Similar to Bad-Homburg, the local hydrological effects are not well represented by global model, but need some site-specific measurements (Wziontek et al 2009). Indeed Zerbini et al (2001) had shown that the gravity signal is highly correlated with a nearby water table, located a few meters underneath the SG.…”