Comparison of Z-R relationships using the Doppler on Wheels, the WSR 88D, and In-Situ Gauge Data

The Doppler on Wheels (DOW), funded by the National Science Foundation (NSF), was recently deployed by the Center for Severe Weather Research (CSWR) at the Florida Institute of Technology (FIT) during a 12 day period from 31 August to 11 September 2015. Five IOPs were conducted during this window for which both DOW and precipitation data were collected. The purpose of this study is to compare in-situ precipitation to estimates obtained from the DOW and Melbourne National Weather Service (NWS) WSR-88D. Different Z-R relationships will be used to convert the radar reflectivity factor to rain rate. X-band radar can be problematic when used for precipitation estimations due to the relatively high attenuation rate. A direct comparison of DOW X band reflectivity comparison with the NWS's S band can provide measure of the degree of attenuation. The observed reflectivity from both radars (at gauge locations) will be used to calculate rainfall rates via standard Z-R relationships and compared to both observed rainfall rates as well as those from the local NWS Z-R algorithm. The observed precipitation will also be used to derive a local Z-R relationship based on the DOW reflectivity.