Satellite-based Earth observation of river discharge, with its global coverage and consistent accuracy, has emerged as a promising alternative to in situ measurements. The Institute of Geodesy (GIS), within the Faculty of Aerospace Engineering and Geodesy at University of Stuttgart has extensive expertise in hydrogeodesy. In recent years, GIS has initiated and contributed to various studies and projects exploring the application of spaceborne geodetic sensors for hydrological research. Some of these efforts focus on deriving river discharge estimates from satellite altimetry, satellite images and satellite gravimetry. Among others, the results of these studies are available through Hydrosat
Below you will find an overview of the space-based extensions to global-scale in situ river discharge measurements, developed by GIS using discharge time series from GRDC and other sources.
Datasets:
The Remote Sensing-based Extension for the GRDC (RSEG) dataset can ingest legacy gauge discharge and remote sensing observations. It is based on a stochastic nonparametric mapping algorithm to extend the monthly discharge time series for inactive GRDC stations, benefiting from satellite imagery- and altimetry-derived river width and water height observations. After a rigorous quality assessment of the estimated discharge, involving statistical validation, tests and visual inspection, results in the salvation of discharge records for 3377 out of 6015 GRDC stations with an average monthly discharge exceeding 10 m³/s. The RSEG dataset regains monitoring capability for 83% of global river discharge measured by GRDC stations, equivalent to 7895 km³/month, providing valuable insight into Earth’s river systems with comprehensive and up-to-date information.
Publication:
A full description of the dataset is available here.
Preview of stations:
Data access:
You can preview and download the time series data for specific stations from the links in this Text file or the Hydrosat Website. The whole dataset can be downloaded in NetCDF format here.
The Satellite Altimetry-based Extension of global-scale in situ river discharge Measurements (SAEM) dataset provides a comprehensive solution for addressing gaps in river discharge measurements by leveraging satellite altimetry. This dataset, developed in collaboration with the Global River Group at Virginia Tech and Institute of Research for Development (IRD-LEGOS), offers enhanced coverage for river discharge estimations by utilizing data from multiple satellite missions and integrating it with existing river gauge networks. It supports sustainable development and helps address complex water-related challenges exacerbated by climate change. The first version of SAEM includes (1) height-based discharge estimates for 8,730 river gauges, covering approximately 88% of the total gauged discharge volume globally. These estimates demonstrate a median Kling-Gupta Efficiency (KGE) of 0.48, surpassing the performance of current global datasets. (2) Catalog of Virtual Stations (VSs): a catalog of VSs defined by specific criteria, including each station’s coordinates, associated satellite altimetry missions, and quality flags. (3) Altimetric Water Level Time Series: time series data of water levels from VSs that provide high-quality discharge estimates. The water level data are sourced from both existing Level-3 datasets and newly generated data within this study, including contributions from Hydroweb.Next, DAHITI, GRRATS, and HydroSat. (4) Non-parametric quantile mapping functions: for VSs, which model the transformation of water level time series into discharge data using a Nonparametric Stochastic Quantile Mapping Function approach.
Preview of stations:
Data access:
You can preview and download the time series data for specific stations from the links in this Text file or the Hydrosat Website. The whole dataset can be downloaded in NetCDF format here.