Assessing daily GRACE Data Assimilation during flood events of the Brahmaputra River Basin: OL and DA outputs

This dataset contains the result of 36 daily and monthly GRACE Terrestrial Water Storage (TWS) Data Assimilation (DA) experiments performed in the Brahmaputra basin, with the purpose of assessing the potential of daily GRACE DA into water balance models for detecting fast evolving water storage anomalies. In these experiments, monthly and daily GRACE(-FO) TWS data derived from the GRACE level 2 (L2) ITSG-2018 product [1,2] were assimilated into the World Wide Water Resources Assessment model [3,4]. The sequential Data Assimilation (DA) was performed through a classical EnKF as well as an EnKS [5] that allows to smoothly disaggregate monthly TWS increments into the daily model timesteps. Different covariance localization degrees were also considered, ranging from no-localization to a 70 km half-radius localization. The experiments were performed for the years 2004, 2007 and 2008, for which the Brahmaputra River Basin was affected by major flooding events. The considered daily and monthly DA approaches were assessed in terms of their impact on the TWS signal as well as their performance on the vertical and horizontal TWS disaggregation. More details about the processing and the main resulting findings can be found in [6]. Citation Please, when using this dataset, remember to cite: L. Retegui-Schiettekatte, M. Schumacher, H. Madsen, and E. Forootan, “Assessing daily GRACE Data Assimilation during flood events of the Brahmaputra River Basin,” Science of The Total Environment, vol. 975, p. 179181, May 2025, doi: 10.1016/j.scitotenv.2025.179181. References [1] T. Mayer-Gürr et al., “ITSG-Grace2018 - Monthly, Daily and Static Gravity Field Solutions from GRACE.” GFZ Data Services, 2018. doi: 10.5880/ICGEM.2018.003. [2] A. Kvas et al., “ITSG-Grace2018: Overview and Evaluation of a New GRACE-Only Gravity Field Time Series,” Journal of Geophysical Research: Solid Earth, vol. 124, no. 8, pp. 9332–9344, 2019, doi: 10.1029/2019JB017415. [3] A. van Dijk, “The Australian Water Resources Assessment System. Technical Report 3. Landscape Model (version 0.5) Technical Description. CSIRO: Water for a Healthy Country National Research Flagship.,” Jan. 2010. [4] A. I. J. M. van Dijk, J. L. Peña-Arancibia, E. F. Wood, J. Sheffield, and H. E. Beck, “Global analysis of seasonal streamflow predictability using an ensemble prediction system and observations from 6192 small catchments worldwide,” Water Resources Research, vol. 49, no. 5, pp. 2729–2746, 2013, doi: 10.1002/wrcr.20251. [5] B. F. Zaitchik, M. Rodell, and R. H. Reichle, “Assimilation of GRACE Terrestrial Water Storage Data into a Land Surface Model: Results for the Mississippi River Basin,” Journal of Hydrometeorology, vol. 9, no. 3, pp. 535–548, Jun. 2008, doi: 10.1175/2007JHM951.1. [6] L. Retegui-Schiettekatte, M. Schumacher, H. Madsen, and E. Forootan, “Assessing daily GRACE Data Assimilation during flood events of the Brahmaputra River Basin,” Science of The Total Environment, vol. 975, p. 179181, May 2025, doi: 10.1016/j.scitotenv.2025.179181.