中文摘要：

为研究晴空回波风场信息在对流性降水天气中的预警应用价值,选取山东省临沂雷达站2008—2013年5—9月的观测数据分析降水晴空回波特征。研究发现：临沂地区5—9月约87%的日数会出现晴空回波,且90%以上出现在距离雷达站100km范围之内,反射率因子多在10-25dBz,具有明显日变化;晴空回波的速度产品能提供有效监测对流性降水出现前的大气低层风场信息,能一定程度反映低层湍流的耗散率,对降水过程有一定的指示性,相关研究成果对降低对流天气漏报率和提高预警提前量有重要意义。

英文摘要：

The characteristics of clear-sky precipitation echoes are analyzed by using Doppler radar data from May to September, 2008 to 2013 to study the application potential of clear-sky echoes to the warning of stratiform precipitation. The results show that the days with clear-sky echoes account for about 87 from May to September in Linyi, with more than 90% of cases within the range of 100 km from the radar station. The reflectivity factors are mostly among 10 to 25 dBz and there is obvious diurnal variation. Clear sky echo velocity products can effectively reflect the wind of lower-layers before stratiform precipitation and lower turbulence dissipation rate in a certain extent, and can also have indication of the precipitation process. These results are meaningful to reduce the missing alarm rates and earlier warning of convective weather.