The global land water storage data set GLWS2.0: a new data set via assimilating GRACE/-FO into a global hydrological model

• Main Authors: Gerdener, H., Jürgen, K., Schulze, K., Döll, P., Klos, A.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Greenland; Antarc*; Antarctica
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5019757

The satellite missions GRACE and GRACE-FO provide a great chance to derive total water storage anomalies (TWSA) from space with global resolution. However, a gap of nearly one year separates the two missions, some months are missing due to technical issues, and with about 300 km the spatial resolution of GRACE/-FO is still too coarse for finer-scale applications. To overcome these challenges, we here provide the Global Land Water Storage data (GLWS2.0) data set. This is a temporally consistent monthly data set of total water storage anomalies, groundwater, soil moisture, and surface water for the time period 2003 to 2019 on a global 0.5° grid over land (except Greenland and Antarctica), publically available on PANGAEA. The data set is developed by globally assimilating GRACE/-FO TWSA into the WaterGAP global hydrology model via the Ensemble Kalman Filter using uncertainty quantification. To our knowledge, only a few studies globally assimilate GRACE/-FO TWSA and most of them focus on hydrological instead of geodetic applications. Thus, here we focus on TWSA as observed by GRACE/-FO and analyze the new data set on the spatial and spectral domain by comparing its specific signatures with those of observations and model simulations, for example via degree variances. Overall, we find that GLWS2.0 is closer to the GRACE/-FO observations than the model simulations while increasing the spatial and spectral resolution. Finally, we use 1030 globally distributed GNSS stations to validate the GLWS2.0 data set and find a better agreement with the station as compared to GRACE/-FO.