Monitoring of melting refreezing cycles of snow with microwave radiometers: The Microwave Alpine Snow Melting Experiment (MASMEx 2002-2003

Abstract—A study of the melting cycle of snow was carried out by using ground-based microwave radiometers, which operated con-tinuously 24 h/day from late March to mid-May in 2002 and from mid-February to early May in 2003. The experiment took place on the eastern Italian Alps and included micrometeorological and conventional snow measurements as well. The measurements con-firmed the high sensitivity of microwave emission at 19 and 37 GHz to the melting-refreezing cycles of snow. Moreover, micrometeoro-logical data made it possible to simulate snow density, tempera-ture, and liquid water content through a hydrological snowpack model and provided additional insight into these processes. Simu-lations obtained with a two-layer electromagnetic model based on the strong fluctuation theory and driven by the output of the hy-drological snowpack model were consistent with experimental data and allowed interpretation of both variation in microwave emission during the melting and refreezing phases and in discerning the con-tributions of the upper and lower layers of snow as well as of the underlying ground surface. Index Terms—Hydrology, microwave radiometry, snow. I