This study was conducted in Central Oklahoma at the National Severe Storms Laboratory (NSSL) site in Norman. Two separate two-dimensional video disdrometers (2DVD) of similar design (manufactured by Joanneum Research in Austria) and a UHF Doppler profiler (manufactured by Radian Inc., currently Vaisala Inc.) were located at NSSL during late April and early May of 2005 for calibration purposes. One disdrometer is owned and operated by NSSL and the other is maintained by the National Center for Atmospheric Research (NCAR). On 21 April 2005, thunderstorms initiated by a dryline in western Texas moved into Oklahoma overnight, and a stratiform region associated with the decaying storms passed over the NSSL site by morning.
Both disdrometers and the collocated vertically pointed profiler operating at 915 MHz were collecting data during the precipitation event. Observations from the two disdrometers and the profiler were used to extract the DSDs, which were then compared to examine agreement between the disdrometers and with the profiler.
This is a preliminary study in preparation for future work involving the polarimetric capabilities of the NSSL KOUN radar. Rainfall measurements from the KOUN radar will be compared to observations from a UHF wind profiler and 2DVD located 30 km from the weather radar site.