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Differentiation Between Melt And Freeze Stages Of The Melt Cycle Using Ssm/I Channel Ratios, David G. Long, Ivan S. Ashcraft
Differentiation Between Melt And Freeze Stages Of The Melt Cycle Using Ssm/I Channel Ratios, David G. Long, Ivan S. Ashcraft
Faculty Publications
Microwave remote sensing detection of snow melt and ablation generally focuses on the detection of liquid moisture in the snow-pack. For ablation estimation, it is important to determine if wet snow is in the process of melting or freezing. The different stages of the melt cycle are observed in the diurnal variation of Tb measurements from the Special Sensor Microwave Imager (SSM/I) over Greenland. SSM/I channel ratios exhibit patterns indicating that they are sensitive to melt and freeze stages of the daily melt cycle. The horizontal to vertical polarization ratio is sensitive to surface wetness associated with melting. The 19-37-GHz …
Observation And Characterization Of Radar Backscatter Over Greenland, David G. Long, Ivan S. Ashcraft
Observation And Characterization Of Radar Backscatter Over Greenland, David G. Long, Ivan S. Ashcraft
Faculty Publications
Characterization of the microwave signature of the Greenland snow surface enables delineation of the different snow facies and is a tool for tracking the effects of climate change. A new empirical observation model is introduced that uses a limited number of parameters to characterize the snow surface based on the dependence of radar backscatter on incidence angle, azimuth angle, spatial gradient, and temporal rate of change. The individual model parameters are discussed in depth with examples using data from the NASA Scatterometer (NSCAT) and from the C-band European Remote Sensing (ERS) satellite Advanced Microwave Instrument in scatterometer mode. The contribution …