강우강도에 따른 S-band와 C-band 레이더의 강수량 추정 비교

Abstract

S-band and C-band radar are generally classified by using 15.00～7.50 cm and 7.50～3.75 cm in wavelength. They are used to the detection of precipitation phenomena and applied to nowcasting and local warning etc. To know the characteristics and differences of precipitation estimation between S-band and C-band radar, radar rain rate by using z=200R1.6 was compared with two radars, relatively. Rain rate which was obtained by radar reflectivity and rain gauge was investigated at each radar. To compare with one hour average rain rate of radar, rain rate of AWS was divided into three rain rate intensity categories : light rain (R < 2.5 mm/h), moderate rain (R = 2.5-10 mm/h), and heavy rain (R > 10 mm/h). Comparing with RMSE (Root Mean Square Error) by each rain rate intensity category, its value of C-band radar had less than S-band radar in light rain and had more than S-band radar in moderate and heavy rain. For the analysis of bias, scatter and error distribution, raw rain rate (Rraw) was divided into three categories : light rain (Rraw = 3 mm/h), moderate rain (Rraw = 6-9 mm/h) and heavy rain (Rraw ≥ 2 mm/h). In every case of rainfall, the bias of S-band radar had lower than C-band radar. The scatter of S-band radar in light rain and heavy rain had higher than C-band radar, however its value of S-band radar had lower than C-band radar in moderate rain. Bias and scatter values were highly shown at high rain rate in both radars. It means that precipitation estimation between radar and rain gauge had lower relationship at higher rain rate in both radars. Error distribution represented at 28.11% overestimation and 71.89% underestimation in S-band radar, whereas C-band radar almost underestimated to 98.77%. Overestimating rates of both radars were shown as the lower percentage at high rain rate. Error distribution of C-band radar had the negative value at heavy precipitation.