Elevation based correction of snow coverage retrieved from satellite images to improve model calibration

摘要

The most widely used method for snow dynamic simulation relies ontemperature index approach, that makes snow melt and accumulation processesdepend on air temperature related parameters. A recently used approach tocalibrate these parameters is to compare model results with snow coverageretrieved from satellite images. In area with complex topography andheterogeneous land cover, snow coverage may be affected by the presence ofshaded area or dense forest that make pixels to be falsely classified asuncovered. These circumstances may have, in turn, an influence oncalibration of model parameters.In this paper we propose a simple procedure to correct snow coverageretrieved from satellite images. We show that using raw snow coverage tocalibrate snow model may lead to parameter values out of the range acceptedby literature, so that the timing of snow dynamics measured at two groundstations is not correctly simulated. Moreover, when the snow model isimplemented into a continuous distributed hydrological model, we show thatcalibration against corrected snow coverage reduces the error in thesimulation of river flow in an Alpine catchment.