The improved hydrological gravity model for Moxa observatory, Germany

The gravity variations observed by the super conducting gravimeter (SG) CD-034 at Moxa Geodynamic Observatory were compared with the GRACE results some years ago. From this comparison we realized that esp. at the location Moxa strong hydrological induced gravity signals are playing a decisive role, which has to be considered in the interpretation of the SG residual data. The basis of the correction model is a local hydrological model of the catchment of the small creek in the valley surrounding the observatory, which has been developed within the cooperation with hydrologists. The transfer of the areal hydrological information to a 3d-gravimetric model has enabled the successful hydrological correction.  The correlation of the observed SG residuals in Moxa with the results provided by GRACE was improved significantly.  

During the last three years the time series of the existing hydrological model were extended in period. In addition, the combined hydrological-gravimetrical modeling could be clearly enhanced. On the one hand, the direct surrounding of the gravimeter and the observatory building has been inserted into the gravimetric model in more detail, including mass changes above the gravimeter sensor in the soil layer on the observatory roof and the snow layer on top of roof and on the topography. On the other hand, the model was extended for ground water. On the poster the modeling is explained and the improved agreement of the gravity effect in the time series with GRACE data is discussed as well as some remaining weakness in exact modeling the dynamic of the flow of water within the slope near the observatory/SG.