Snow Depth Measurements using Ground-Based FMCW Radar Measurements Of Dry Snowpacks During December Of The 2006-07 NASA CLPX-II

Ground-based microwave radar measurements of snowpacks were made during the December Intensive Observation Period (IOP) of the 2006-07 NASA Cold Land Processes Experiment (CLPX). Measurements, which covered a wide range of sensor parameters (4-18 GHz, multiple incidence angles, polarizations, bandwidths), were made at 5 different locations within the 100 km x 10 km study region in Northern Colorado and spanned a wide range of dry snowpack conditions. Recent improvements in the portability and accuracy of our Frequency Modulated Continuous Wave (FMCW) radar system, incorporating a new lightweight sled for improved mobility, allowed continuous measurements to be made from the centimeter to the kilometer scale. Measurements were made with the radar mounted 0.5 m above the snow surface, which with post-processing can be used to estimate snow depth, SWE, and the location of major stratigraphic boundaries. The radar was also mounted at a height of 2.3 m (far-field) at oblique incidence angles of 30 and 45 degrees to simulate backscatter as measured over the study site by a coincident airborne Ku-band scatterometer, as well as to make backscatter measurements covering a wide range of sensor parameters. All radar measurements were geo-located with survey-grade GPS (2-10 cm accuracy). As an initial step in the interpretation of this large database, in this paper we focus on radar-derived snow depth estimates at three different sites with depths spanning more than an order of magnitude (0.05 0.98 m), and compare them quantitatively with the coincident manual depth measurements.