This joint effort included a quantitative comparison of rainfall characteristics in Jefferson County, KY using radar and rain gage information. An operational high-resolution rain gage network is monitoring rainfall in Jefferson County. The network is supported by the local municipal sewer company and consists of 30 rain gages distributed throughout the county. These gages provided a unique opportunity to collect and assimilate a useful database of rainfall measurements for comparison with the WSR-88D at the Louisville NWS WSFO.
The primary research task was a rainfall accumulation comparison study using
WSR-88D Level II data and the high-resolution rain gage data. Data from one
rain event from the summer season of 1995 was available for analysis (August
5-6, 1995). The heavy rainfall that occurred on this day was the product of
a large rain system moving across the country as remnants of Hurricane Erin.
The results for this particular event indicated that the radar estimated precipitation
accumulations were less than the gage values. For the storm total time period,
the radar estimated depth was approximately 50% of the gage depth. Additional
work with this event is being conducted to refine the analysis and develop a
more comprehensive set of performance criteria.