Comparison Of Millimeter-wave Radar Observations Of Snow With Energy And Mass Transfer Simulation

Abstract

This study compares variations in measurements of FM-CW radar backscatter with simulated snow properties from model based on mass and energy transfer and surface energy budgets. The radar frequency ranges from 26.5 - 40 GHz. The backscatter response to wet snow is highly sensitive to fluctuations of the surface energy exchange when the snow has a low liquid water content. Analysis of the net radiation, turbulent exchange and net energy budget in the top few millimeters of snow provides a reasonable explanation of the observed backscatter variations. The near-surface liquid water content simulated by the model does not show the magnitude of changes expected when compared with the radar return. This allows a detailed evaluation of model algorithms, which account for liquid water drainage and evaporation from the surface as well as densification and consolidation of the top snow layer.