A first continuous and distributed satellite-based mapping of river discharge over the Amazon

River discharge integrates many water-related processes over land, it is crucial for understanding inland water. Unfortunately, in situ measurements are very sparse at the global scale. This study presents a totally new approach for the mapping (i.e. spatially continuous estimate) of the river discharge based on satellite observation of hydrological variables and the water budget balance. First continuous satellite estimate of three water components (precipitation, evapotranspiration, and total water storage change) are corrected at basin scale using river discharge from a few gauge measurements. Secondly, the water budget is balanced at the grid level using flow direction for horizontal water exchange. This new approach is therefore based solely on satellite products and in situ measurements without the use of any dynamical model (except river map). The methodology is evaluated with the river dynamic model  CaMa-flood, altimetric water surface level (WSL) and surface water extent satellite estimate. While the spatial pattern of extreme events cannot be well represented only by in situ gauges information, our study shows the added value of the mapping to better describe these events. As hydrological application, our method can be used in synergy with all the altimetric stations to create discharge-WSL pair data, which will benefit to advanced applications.