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

A study of the melting cycle of snow was carried out by using ground based microwave radiometers, which operated continuously 24 hours/day from end of March to mid May in 2002 and from mid February to early May in 2003. The experiment took place in the eastern Italian Alps and included micro-meteorological and conventional snow measurements as well. The measurements confirmed the high sensitivity of microwave emission at 19 and 37 GHz to the melting-refreezing cycles of snow. Moreover, micro-meteorological data made it possible to simulate the snow density, temperature and liquid water content through a hydrological snowpack model and provided additional insight into these processes. Simulations obtained with a two layer electromagnetic model based on the Strong Fluctuation Theory and driven by the output of the hydrological snowpack model were consistent with experimental data and allowed interpretation of both the variation of microwave emission in the melting and refreezing phases and in separating the contributions of the upper and lower layers of snow as well as of the underlying ground surface.