摘要
统计分析了陕西中北部 1991～ 2 0 0 1年 4个 711雷达站附近 15个气候观测站日降雨量大于等于 5mm降水过程的时空分布及雷达回波特征。陕西中部适宜人工增雨的时段为 2月 10日至 11月 15日 ,北部为 2月 2 5日至 11月 10日。陕西降雨性层状云 0℃层高度变化范围为 3 .6 3～5. 0 3km ,平均高度为 4 6 5km ,融化层强回波区厚度为 0 . 4～ 1. 0km。冷云、暖云降雪(雨 )量级较小 ,不适宜大范围开展人工增雪 (雨 )作业。适宜人工增雨的稳定性层状云雷达回波特征为 :PPI回波结构密实 ,范围大于 30km ,雷达回波强度大于等于 30dBz,RHI显示云顶高度大于等于 5 . 8km或者融化层明显 ,强度达 30dBz以上。适宜人工增雨的混合性层状云雷达回波特征为 :PPI有明显强回波中心 ,强度大于等于 30dBz,15dB回波宽度大于等于2 5km ,回波最大高度大于等于 5km ;或者融化层明显 ,雷达观测融化层下挂回波明显倾斜或呈锯齿型排列。
The data from four Model-711 Radar stations located in the middle and northern parts of Shanxi Province from 1991 to 2001 were analyzed, and the variations of the precipitation processes with a daily rainfall of more than 5 mm from 15 climatological stations nearby the radar stations were statistically calculated. The suitable period for precipitation enhancement in the middle part is from 10 February to 15 November and that in the northern part is from 25 February to 10 November. The 0 ℃ level for precipitable stratiform clouds ranges from 3 63 km to 5 03 km with its average being 4 65 km. The strong echo depth of the melting layer is from 0 4 km to 1 0 km. The radar echo features of stable and mixing stratiform clouds suitable for rain enhancement are summarized.
出处
《气象科技》
2005年第1期87-90,共4页
Meteorological Science and Technology
基金
科技部"西部开发科技行动""黄河中游(陕甘宁)干旱半干旱地区高效人工增雨(雪)技术开发与示范"项目 (2 0 0 1BA90 1A41)资助
