Abstract
This study proves the measurement capability of a Ka-band frequency modulated continuous wave (FMCW) Doppler weather radar (KaDR) developed for the Japanese cloud seeding experiments for precipitation augmentation (JCSEPA) research project. To continuously monitor precipitation and clouds with reduced maintenance costs, KaDR uses a traveling wave tube (TWT) transmitter which is originally designed for satellite communication. The TWT produces signals with a frequency of 35.25 GHz (8-mm wavelength) and a peak power of 100 W. Because the peak power of the TWT was small compared with conventional Ka-band weather radars which use transmission tubes, KaDR transmits FMCW in order to attain enough sensitivity and range resolution. Using the dataset collected from 1700 JST 25 October to 0300 JST 26 October 2009 at Shigaraki MU Observatory (34°51'N, 136°06'E, 386 m above the sea level), the equivalent radar reflectivity factor (Ze) and Doppler velocity (Vd) measured by KaDR were compared with micro ran radar (MRR). To evaluate Ze (Vd) measured by KaDr, a correlation coefficient and regression line were computed using a scatter plot between the two Zes (Vds). High correlation coefficient of 0.904 (0.912) and regression slope of 1.023 (1.038) between the two Zes (Vds) demonstrate the capability of KaDR to measure Ze and Vd quantitatively.
