Various GRACE monthly gravity field solutions have been produced by several institutions including the official GRACE data processing centers, GFZ, CSR, and JPL, and additional processing centers such as AIUB, GRGS, and ITSG at TU Graz. To make use of the solutions from different processing strategies together, we can combine the individual solutions.
The combined solution will have considerable benefits. First of all, the combined solutions can reduce systematic errors specific for certain processing centers. They will be reliable and consistent regardless of weakness of individual solutions. Also, they will be beneficial especially for the users of GRACE gravity solutions without advanced knowledge or preference. In the EGSIEM project, we plan to establish a scientific combination service of GRACE monthly gravity solutions.
To evaluate the benefits of combination, the currently available individual GRACE monthly solutions at the ICGEM website were combined with different weighting schemes. The graphs below show the decreasing trends of mean equivalent water heights (MEWH) of Greenland from the different individual solutions and a tested combined solution. As you can see in the figures, the combined solution shows that it is less scattered than the individual solutions, especially in the unfiltered case.
The first result of the combination study was presented in the EGU General Assembly 2015, Geodätische Woche 2015, and the seminar series in Astronomical Institute of University of Bern (AIUB). If you want to learn more about the result, you can check the following links:
