Microwave radiometric sensing of the physical parameters of snow

A field and laboratory measurement program sponsored by the Office of Naval Research and CRREL, is being conducted to determine the response to microwave radiometers to various snow conditions. The field portion of the program was carried out within the confines of Crater Lake National Park, with data obtained from new fallen powder snow and old metamorphosed snow. The measurements were made at three frequencies, 13.5 Ghz, 27 Ghz, and 94 Ghz, (one Ghz equals 10 to the 9th power cycles per second), with microwave temperatures recorded for both horizontal and vertical polarizations at viewing angles ranging from nadir to local horizon. Similar laboratory measurements were made of artificial snow made in an environmental chamber in which snow temperatures and moisture content are controlled. The results of these studies show that different microwave frequencies do not behave in the same manner as the moisture content of the snow. The measurement of these parameters from a remote sensing platform over broad areas of major watersheds would greatly aid in the management of water resources.