HR: 0800h
AN: C31A-0296    [Abstracts]
TI: Snowfall Retrivals Using a Video Disdrometer
AU: * Newman, A J
EM: andrew.newman@und.nodak.edu
AF: University of North Dakota, Department of Atmospheric Sciences P.O. Box 9006, Grand Forks, ND 58202-9006 United States
AU: Kucera, P A
EM: pkucera@aero.und.edu
AF: University of North Dakota, Department of Atmospheric Sciences P.O. Box 9006, Grand Forks, ND 58202-9006 United States
AB: A video disdrometer has been recently developed at NASA/Wallops Flight Facility in an effort to improve surface precipitation measurements. One of the goals of the upcoming Global Precipitation Measurement (GPM) mission is to provide improved satellite-based measurements of snowfall in mid-latitudes. Also, with the planned dual-polarization upgrade of US National Weather Service weather radars, there is potential for significant improvements in radar-based estimates of snowfall. The video disdrometer, referred to as the Rain Imaging System (RIS), was deployed in Eastern North Dakota during the 2003-2004 winter season to measure size distributions, precipitation rate, and density estimates of snowfall. The RIS uses CCD grayscale video camera with a zoom lens to observe hydrometers in a sample volume located 2 meters from end of the lens and approximately 1.5 meters away from an independent light source. The design of the RIS may eliminate sampling errors from wind flow around the instrument. The RIS operated almost continuously in the adverse conditions often observed in the Northern Plains. Preliminary analysis of an extended winter snowstorm has shown encouraging results. The RIS was able to provide crystal habit information, variability of particle size distributions for the lifecycle of the storm, snowfall rates, and estimates of snow density. Comparisons with coincident snow core samples and measurements from the nearby NWS Forecast Office indicate the RIS provides reasonable snowfall measurements. WSR-88D radar observations over the RIS were used to generate a snowfall-reflectivity relationship from the storm. These results along with several other cases will be shown during the presentation.
DE: 1863 Snow and ice (1827)
DE: 0394 Instruments and techniques
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting