Stability of AOD1B RL07

The Atmosphere and Ocean non-tidal De-aliasing Level-1B (AOD1B) product is widely used in satellite gravimetry to correct for transient effects of atmosphere-ocean mass variability that would otherwise alias into monthly-mean global gravity fields. The most recent release is based on the global ERA5 reanalysis and ECMWF operational data together with simulations from the general ocean circulation model MPIOM consistently forced with fields of the same atmospheric data-set.

To fully utilise the potential of geodetic data for climate applications, addressing long-term stability in background (or observation-reduction) models is critically important. Spurious trends, low-frequency signals or bias jumps in the background model data can be, if unaccounted for, be introduced into the final gravity solutions and erroneously interpreted in geophysical analyses. We here present the recently published new release RL07 of AOD1B, which is produced from 1975 onwards, and analyse its stability both on long time-scales through the study of trends as well as short-scale stability through the analysis of 3 hourly tendencies. Results are compared to other atmospheric reanalyses and the previous version of AOD1B. A special focus is placed on the transition from ERA5 to ECMWF operational atmospheric data and model changes in ECMWFs IFS.