Geodetic in-situ observations are always effected by environmental parameters like atmosphere, ocean and hydrology. It is often criticised that seasonal effects accounted for global network analysis do not significantly improve the resulting parameters. In a local case study at Medicina, space geodetic (GPS and VLBI) and gravity observations (SCG and FG5) are used together with environmental observations and models to provide significant information both on the seasonal fluctuation as well as on the linear and non-linear long-term trend in height. Models of seasonal height and gravity components have been achieved by accounting for loading and mass effects, by atmosphere, non tidal ocean and the local hydrology. This last component shows to be a major contribution of the seasonal variations not only in terms of loading and mass variations but also for soil consolidation effects induced by water table decrease / increase on the clayey soil in Medicina. The local hydrology is an important component to understand the seasonal effects but it is difficult and / or expensive to get sufficient information at the observation sites. It will be demonstrated that regional and global information on hydrology, the Hydrological Balance and GRACE results used as input can satisfactory replace locally observed environmental data. The experiment carried out in Medicina demonstrates that only the combined reduction of the effect of environmental parameters will improve the overall analysis. Rigorously applied it allows to study linear and non-linear long-term station variations. There is a high probability that the consequent consideration of environmental parameters will have positiv effects on the long-term evolution of the global reference frame.

A combined GPS and Gravity analysis to study the effect of environmental parameters

ZERBINI, SUSANNA;MATONTI, FRANCESCO;
2005

Abstract

Geodetic in-situ observations are always effected by environmental parameters like atmosphere, ocean and hydrology. It is often criticised that seasonal effects accounted for global network analysis do not significantly improve the resulting parameters. In a local case study at Medicina, space geodetic (GPS and VLBI) and gravity observations (SCG and FG5) are used together with environmental observations and models to provide significant information both on the seasonal fluctuation as well as on the linear and non-linear long-term trend in height. Models of seasonal height and gravity components have been achieved by accounting for loading and mass effects, by atmosphere, non tidal ocean and the local hydrology. This last component shows to be a major contribution of the seasonal variations not only in terms of loading and mass variations but also for soil consolidation effects induced by water table decrease / increase on the clayey soil in Medicina. The local hydrology is an important component to understand the seasonal effects but it is difficult and / or expensive to get sufficient information at the observation sites. It will be demonstrated that regional and global information on hydrology, the Hydrological Balance and GRACE results used as input can satisfactory replace locally observed environmental data. The experiment carried out in Medicina demonstrates that only the combined reduction of the effect of environmental parameters will improve the overall analysis. Rigorously applied it allows to study linear and non-linear long-term station variations. There is a high probability that the consequent consideration of environmental parameters will have positiv effects on the long-term evolution of the global reference frame.
Dynamic Planet 2005
Richter B.; S. Zerbini; F. Matonti; T. vanDam; F. Rocca
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/7238
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