Variation of Rainrate and Radar Reflectivity in Busan Area and Its Measurement by Clouds Type
Variation of Rainrate and Radar Reflectivity in Busan Area and Its Measurement by Clouds Type
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釜山地区降雨率和雷达反射率变化及其云类型测量
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
Kyung
中科院分区：
文献类型：
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作者：
C. You;Dong;M. Jang;Hyo;Jung;Kyung
马歇尔和帕尔默的Z= 200 R 1.6用于层状降水型时，对对流云降水的估算存在许多不确定性。为了更准确地计算和预测降水量，需要在沿海地区测量适当的Z-R关系，因为釜山的云和降水系统的变化和移动比其他地区快。利用降水发生传感器系统（POSS）2001年和2002年5次和11次降水事件的日变化资料，分析了Z-R关系的日变化规律，并计算了新划分的降水类型的日变化规律。降水量的变化与日雷达反射率、持续时间和降雨率的关系可用幂律回归表示。结果表明，A系数和B系数分别为98~669和1.31~1.67。利用Tokay和Short（1996）的γ DSD因子N 0和Λ，得到层状云和对流云相互作用时的降水率R。对流云的A值一般为78~91，B值平均为1.6±0.1，而层状云的A值为386~481，B值为1.5。考虑到层状云降雨中没有出现的5.5 μ m/h的阈值，Z-R关系的A值在两种云型下都有增加的趋势，而非分类雨率。
Z=200R 1.6 by Marshall and Palmer which is applied at stratiform rainfall type has contained many uncertainties for the rainfall estimation of convective clouds. To calculate and forecast the precipitation amount more accurate, measurement of adequate Z-R relationship is needed at coastal area, since the variation and movement of clouds and precipitation system are faster in Busan than other areas. In this study the variations of daily Z-R relationship and its calculation with respect to new classified precipitation types were accomplished using the DSDs obtained by a disdrometer, POSS (Precipitation Occurrence Sensor System) at each 5 and 11 precipitation event in 2001 and 2002 year. The variation of precipitation amount by power law regression was expressed depending on the daily radar reflectivities, duration time and rain rates. As a result, coefficient A and b values showed at 98~669 and 1.31~1.67 ranges. Using gamma DSD factors N0 and Λ by Tokay and Short (1996), rain rates R were obtained at stratiform and convective clouds type each other. Generally, A values of convective clouds had 78~91 and b values had mean 1.6±0.1, however, their values were shown to the 386~481 and 1.5 at stratiform clouds type, respectively. As a consideration of the threshold value of 5.5 ㎜/h which is not occurred in the case of stratiform rainfall, A values of Z-R relationship had a tendency of increase at both clouds type in contrast to non-classification rain rates.