TUD-L2B-EWH\_UNC-GRACE: A Global Level‑2B GRACE(-FO) EWH Uncertainty Product

Michal Cuadrat-Grzybowski , Joao G. Teixeira da Encarnacao

We present a globally gridded Level-2B GRACE(-FO) equivalent water height (EWH) data product that provides a complete characterisation of uncertainty, enabling easy direct use in Earth system research. Unlike conventional uncertainty estimates that either require propagation of full normal matrices or rely on empirical assumptions about temporal and spatial correlations, TUD-L2B-EWH\_UNC-GRACE combines ensemble statistics from multiple independently processed Level-2 solutions to quantify uncertainties, including contributions from ocean tide model differences, parametrization strategies, and uncertainties in the Atmosphere and Ocean De-aliasing product. Post-processing uncertainties, related to filtering effects and Glacial Isostatic Adjustment (GIA) model variability, are quantified using a known-pair approach and an ensemble of 56 GIA models, respectively. Uncertainty fields are provided for a suite of anisotropic filtering strategies (DDK2–DDK7), supporting the assessment of filtering strength, leakage effects, and processing-choice impacts on total uncertainty. In addition to the standard Level-2B configuration, the ancillary TUD-L2B-EWH\_UNC\_noSLR-GRACE product, in which low-degree coefficients ($C_{2,0}$ and $C_{3,0}$) are not replaced by Satellite Laser Ranging estimates, allows users to isolate uncertainties associated with low-degree coefficient treatment. TUD-L2B-EWH\_UNC is the first Level-2B EWH dataset to deliver end-to-end, gridded uncertainty fields, to facilitate robust applications in hydrology, glaciology, solid-Earth, and oceanographic studies. Ancillary tidal corrections and climatological fits, for long-term climatological studies, are distributed separately in the TUD-L2B-EWH\_CLIM-GRACE, TUD-L2B-EWH\_CLIM\_CORR-GRACE and TUD-L2B-EWH\_CLIM\_LEAKAGE-GRACE products.