Improved modelling of non-tidal mass variations for optimized gravity fields analysis

IMPLY

High-frequency mass variations cannot be measured adequately from space due to undersampling. They are removed from the measurements beforehand using geophysical models (de-aliasing). Any model error fully propagates into the final gravity field results. IMPLY aims in the improved modelling of non-tidal short-term mass variations (ocean, atmosphere and hydrology) and their uncertainties in order to optimize GRACE, GOCE and next generation gravity field data analysis. In particular the expected results are:  

1. Improved geophysical models of global mass variations specifically related to long-term stability and standards applied in these models.
2. Studies on the significance of the use of hydrology models and/or GRACE daily solutions for de-aliasing.
3. Generating a time series of refined de-aliasing coefficients. This includes global solutions to be applied for standard gravity field analysis as well as regional refinements needed by other projects of SPP1257.
4. Review, extension, speed up of de-aliasing and error-propagation software developed before within the SPP 1257.

Results of IMPLY will lead to improved modelling of high frequency time-variable mass variations and their uncertainties. This not only drives the performance of current gravity field missions, but also is one of the main issues to be solved for next-generation gravity field missions with significantly improved observation accuracy.