New research is finding that satellite-based radar remote sensing techniques are particularly well-suited for quantifying the transition of remote boreal regions from a frozen to a thawed condition. The implications for studying global warming are far reaching. If the timing or areal extent of this freeze/thaw transition were to change significantly, measurable changes in boreal climate, hydrology, and biogeochemistry would result.
Abrupt transition from frozen to thawed conditions occurs each year over roughly 50 million km2of the Earth's remote terrestrial surface at latitudes above 40°N. Radar remote sensing works well to capture this transition because of the way electromagnetic radiation at radar wavelengths interacts with polar water molecules in solid and liquid states. Also, radar has the substantial advantages at high latitudes of both penetrating through clouds and not requiring solar illumination of the land surface.