Evaluation of sub-monthly oceanographic signal in GRACE "daily" swath series using altimetry

Abstract

Bottom pressure estimates from three different Gravity Recovery and Climate Experiment (GRACE) series (an experimental Center for Space Research (CSR) swath series, ITSG2016, and ITSG2018) and two global ocean models (OMCT and MPIOM) are compared to Jason altimetry sea level anomaly estimates in order to determine the accuracy of the GRACE and model data at sub-monthly timescales. We find that the GRACE series are capable of explaining 25%-75% of the sub-monthly altimetric variability over most of those ocean regions that have high signal strength. All three GRACE series explain more of the sub-monthly variability than the de-aliasing products they were created with. Upon examination over finer frequency bands, the GRACE series prove superior at explaining the altimetric signal for signals with periods as short as 10d.