Abstract
The study of the cryosphere by means of remotely sensed hyperspectral data in the domain of reflected solar radiation (400-2500 nm) represents an active field of research. This study aims at exploiting the richness of information deriving from hyperspectral satellite data for estimating snow grain size and snow albedo. These two parameters are closely correlated since the albedo is affected by the snow grain size, especially in the infrared region of the electromagnetic spectrum, where it decreases as the grain size increases. The analysis of these parameters is therefore essential for a better understanding of the mechanical and thermodynamic processes occurring within the snowpack.
In this context, PRISMA hyperspectral data represent an important opportunity for the development and optimization of algorithms for the estimation of snow physical parameters and are particularly well suited for investigations in complex morphologies typical of the alpine areas. The test sites are indeed located in Italian Alps and the validation is carried out by exploiting existing data as well as data collected during ad hocfield campaigns. Different algorithms have been applied in order to identify the best performances for the estimation of these challenging parameters. The validation of these parameters is very complex for different reasons: the measurement of grain size is subject to the sensitivity and accuracy of the operator; collecting a lot of data is time-consuming; regarding the albedo, automatic stations (albedometers) often provide unreliable measurements. For these reasons, having a consistent validation dataset is not so easy. In any case, despite showing a slight general underestimation, the first results relating to grain size estimation are promising and further analyses are in progress in order to strengthen the validation dataset and consolidate the results.
This work is carried out within Contract “SCIA” n. 2022-5-E.0 (CUP F53C22000400005), funded by ASI in the “PRISMA SCIENZA” program. PRISMA Product - © Italian Space Agency (ASI) (year of acquisitions). All right reserved.