Massentransporte und Massenverteilungen im System Erde  
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Daily GRACE gravity field solutions

For the first time daily gravity field snapshots have been derived from GRACE level 1B data using a Kalman smoother approach. When calculating independent solutions, such an extreme increase in temporal resolution would lead to a loss in redundancy and therefore to a decreasing accuracy of the estimated parameters with decreasing time span. It can be assumed, however, that the gravity field does not change arbitrarily from one day to the next. The information about the temporal correlation patterns has been derived from geophysical models (hydrology, atmosphere and ocean). This knowledge has been utilized within the framework of a Kalman smoother estimation procedure to enhance the temporal resolution without losing spatial information. For further information see Kurtenbach et al. 2009.

 

RMS temporal RMS in equivalent water heights of the daily GRACE solutions displayed for each location. The time series in the upper left of the figure illustrates the temporal evolution of the daily solutions as averaged water heights in the Congo river basin.

The daily GRACE solutions are part of the new global GRACE gravity model ITG-Grace2010 calculated at University of Bonn and can be downloaded via the website.

 

References:

Kurtenbach , E. , Mayer-Gürr , T. , Eicker , A. : Deriving daily snapshots of the Earth's gravity field from GRACE L1B data using Kalman filtering, Geophys. Res. Lett., 36, 2009

 

Mayer-Gürr , T. , Kurtenbach , E. , Eicker , A. : ITG-Grace2010 gravity field model.

URL: www.igg.uni-bonn.de/apmg/index.php.