Estimating snow cover from publicly available images

In this paper we study the problem of estimating snow cover in mountainous regions, that is, the spatial extent of the earth surface covered by snow. We argue that publicly available visual content, in the form of user generated photographs and image feeds from outdoor webcams, can both be leveraged as additional measurement sources, complementing existing ground, satellite and airborne sensor data. To this end, we describe two content acquisition and processing pipelines that are tailored to such sources, addressing the specific challenges posed by each of them, e.g., identifying the mountain peaks, filtering out images taken in bad weather conditions, handling varying illumination conditions. The final outcome is summarized in a snow cover index, which indicates for a specific mountain and day of the year, the fraction of visible area covered by snow, possibly at different elevations. We created a manually labelled dataset to assess the accuracy of the image snow covered area estimation, achieving 90.0% precision at 91.1% recall. In addition, we show that seasonal trends related to air temperature are captured by the snow cover index.Comment: submitted to IEEE Transactions on Multimedi

Parabolic through demonstrator for high temperature solar energy in Sardinia using gas as heat transfer fluid

Estate Lab project is aimed towards building up a laboratory for the development of high temperature concentrated solar technologies in Sardinia, Italy. The main purpose of the R&D activities is the construction of a demonstration plant for the production and storage of energy at 550°C by means of sun-heated gaseous fluids. The plant will be built in the industrial area of Macchiareddu, nearby Cagliari and mainly consists of two 100 m. lines of parabolic trough collectors and one thermocline pebble-bed energy storage for each line. The Estate Lab project demonstrator will be developed in order to prove the good findings of the research activities and to validate the expected results. The optimisation of the system will be also investigated for a proper scale up of the plant to a commercial size for bulk electricity production. This paper presents the key technical data of the experimental facility and the significant and innovative aspects of the project