Colloquium: 15 February – Special time and place (12:00 pm and EN6060)

Abstract:

Gages and snow pillows are used to monitor snowfall throughout the Rocky Mountain region.  A disadvantage of these systems is that region-wide snow amounts are extrapolated from point measurements.  Radars offer an alternative to this approach; they measure backscattered microwave energy (Z), from which snowfall rate (S) can be estimated with high spatial and temporal resolution.  The accuracy of radar-estimated snowrates hinge on the parameterization used to relate Z to S.  This work focuses on the development of a Z-to-S parameterization for the National Weather Service radar operated in Cheyenne, WY.  Since temperature can influence both Z and S, a surface temperature-dependent, and a cloud temperature-dependent, Z-to-S parameterization are developed.  The Z-to-S parameterizations are based on measurements made with the Cheyenne, WY Weather Surveillance Radar and a heated-plate snowrate sensor.  The latter was operated at a site located 25 km northwest of Cheyenne; data was collected in winter orographic snowstorms between January and March 2006.