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 GRACE-FO time-series contributing to the RL02-combination.

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 ice melt 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	AIUB	CSR	GFZ	GRGS	HUST	ITSG	JPL	LUH	COMB
08/2024