Elimination of chaff echoes in reflectivity mosaic of operational weather radar network using infrared satellite data

In terms of an accurate nowcasting and quantitative precipitation estimation, the discrimination and elimination of chaff echoes are an essential issue of quality control. It is difficult to identify and remove chaff echoes based on the properties derived from radar measurements due to similarity of radar reflectivity and radial velocity between chaff echoes and precipitation echoes. Chaff echoes removal algorithm based on the extra measurements such as a satellite data is necessary. In this study, new removal algorithm of chaff echoes in two-dimensional reflectivity mosaic of the height of 1.5km using the brightness temperature(TB) obtained from MTSAT-1R has been developed. This algorithm was based on the fact that chaff is not appeared in infrared satellite data of MTSAT-1R, while chaff is detected as echoes in radar mosaic. The algorithm were verified for three cases of only chaff, chaff mixed with convective storm and chaff covered with cloud during a period of 1 May to 15 June 2010. The algorithm has excellent performance for the cases of only chaff and chaff mixed with convective storm. It is also founded that the performance of the algorithm depends on the threshold varied monthly. TB are statistically analyzed in order to optimize a threshold of TB and monthly TB are finally suggested.