Hydraulic model calibration using remote-sensing data: the usefulness of ERS-2 and ENVISAT water surface levels

The calibration phase of hydrological and hydraulic models usually rely on the availability of in-situ observations which may be limited, or absent, in vast areas of the globe. In this context, the recent advances in radar-altimetry technology may represent a valid alternative for providing remotely sensed water level for lakes and rivers, even located in poorly-gauged area. The present analysis mainly aims to investigate the usefulness of water surface elevation data provided by ERS-2 and ENVISAT satellites for the calibration of hydraulic numerical models. Focusing on a 130 km reach of the middle-lower portion of the Po river, we inves-tigated the opportunity of calibrating a quasi two-dimensional (quasi-2D) numeri-cal model for intermediate streamflow conditions. Referring in turn to in-situ and remotely sensed water levels we calibrated the model comparing the results in terms of calibrated roughness coefficient. Our analysis points out that even if the accuracy of a single satellite measurement is not particularly high, a large re-motely sensed data-set can effectively describe the hydrometric regime in a given cross-section and can integrate field observations, improving the knowledge on the streamflow regime and enhancing the model calibration.