Application and analysis of the radar precipitation estimation over the South Korea

Radar-AWS (Automatic Weather System) Rainrate (RAR) system estimating the quantitative precipitation by using the weather radars in real-time has been developed over the South Korea and operated in Korea Meteorological Administration (KMA) from January 2006.

The RAR system consists of the following four steps: 1) the quality control of the volumetric reflectivity and the production of its 1.5-km CAPPI (Constant Altitude Plan Position Indicator) of each radar, 2) the 10-min average of the pixel-based rainrate of rain gauges within the radar observation area, 3) the hourly Z-R computation by the minimization the difference between the 10-min CAPPI and raingage rainrate during one latest hour and the rainfall estimation updated at each 10 minutes, and 4) the composition of the 10-radar estimated rainfall data.

In this study, the application of the bias adjustment for the improvement of RAR accuracy is examined with respect to the accumulated period of the radar and the raingauge precipitation and analyzed for the accuracy of these radar precipitation estimations. RAR applied the bias adjustment algorithm shows the accuracy improvement in the estimating quantitative precipitation. In the comparisons of time period, the bias adjustment for instantaneous accumulated period gives much better than that of the longer periods in the convective events.