Global plots of monthly anomalies in geoid heights

Monthly anomalies are derived by subtraction of a deterministic signal model (bias, trend, annual and semi-annual variations) from the monthly solutions. The signal model is fitted to the monthly means of all time-series in the time period 2004-2010, and extrapolated to earlier or later epochs to avoid poor quality solutions in the early or late phase of the GRACE mission to impact the signal model (each month is weighted equally).

For each spherical harmonic coefficient an individual model is fitted, the signal model is evaluated at the middle epochs of the monthly solutions and then the spherical harmonic coefficients are expanded into global grids, applying a 400 km Gauss filter.

Anomalies over continents are mainly due to non-periodic hydrological signals or non-linear mass trends in polar regions. These should be consistent in all time-series. Anomalies over the oceans are dominated by noise and allow for a rough noise assessment of the different time-series.

month	AIUB2	APM23	CSR6	GFZ6	GRGS	HUST23	ITSG	JPL	SUS23	Tongji23	COMB
01/2004
02/2004
03/2004
05/2004
06/2004
11/2004
12/2004
01/2005
02/2005
04/2005
05/2005
06/2005
07/2005
08/2005
09/2005
10/2005
11/2005
12/2005
01/2006
02/2006
03/2006
04/2006
05/2006
07/2006
08/2006
11/2006
12/2006
01/2007
02/2007
03/2007
04/2007
05/2007
06/2007
07/2007
08/2007
09/2007
10/2007
11/2007
12/2007
01/2008
02/2008
03/2007
04/2008
05/2008
06/2008
08/2008
09/2008
10/2008
11/2008
12/2008
01/2009
02/2009
03/2009
04/2009
05/2009
06/2009
07/2009
08/2009
10/2009
10/2009
11/2009
12/2009
01/2010
02/2010
03/2010
04/2010
05/2010
06/2010
07/2010
08/2010
09/2010
10/2010
11/2010
12/2010