Two experimental brightness temperature data sets are revisited: A ground-based campaign of terrestrial snow in 1985 and an airborne research program of snow on lake ice in 2007-2014. Both data sets were obtained in southern Finland using multi-frequency microwave radiometers. In this paper both the overall behavior of the brightness temperature during the ground-based campaign and results from the intensive data collection period on April 12-13 (melt/freeze cycle) are discussed. Additionally, selected results from the airborne snow/lake ice program are compared with theoretical values. Two theoretical models are used for simulation.