基于遥测雨量数据的地形对降水特性的影响研究

以浙江省东部的宁波市鄞州区为例,采用15 min间隔的遥测降水数据,根据最小事件间隔时间对降水事件进行划分,探讨了地形对降水特性的影响在时间和空间上变化的复杂性。结果表明,不同年份年降水总量及降水频次与高程的相关关系较为显著,山区降水次数的增多对其降水量的增大有一定影响。另一方面,降水强度及历时与高程的关系比较复杂,地形对各种天气条件控制下不同类型降水的影响并不一致。降水强度小于2 mm/h以及降水历时介于2～5 h的降水频次随高程增大存在增加的趋势,且不同年份的这种增长趋势较为接近;而其它高强度、短历时或长历时的降水频次与高程的关系则比较复杂,地形对这些类型降水的影响具有较大的随机性。

Precipitation Characteristics Based on Telemetering Pluviograph Data:Orographic Effects

Based on telemetering pluviograph data at the intervals of 15 minutes,the precipitation events were extracted according to minimum inter-event time,and the complex orographic effects on precipitation characteristics were analyzed in spatial and temporal scales in Yinzhou District,located in Ningbo City,Eastern Zhejiang Province.As confirmed by the results,the amounts and frequency of precipitation demonstrated a significantly close correlation with the elevations in various years,and the relative larger total rainfall amounts in the mountainous areas were partly attributed to the increments of precipitation frequencies.On the other hand,the relationships between rainfall intensity,duration and elevation were found more complex,and the orographic effects were not consistent on different types of precipitation controlled by various weather conditions.The number of rainfall events that had intensities less than 2 mm/h or durations of 2 to 5 hours increased significantly as the elevation rose,and this trend had been observed consistently in different years.The relationship between elevations and the frequencies of the rainfalls with high-intensity,or shorter and longer duration was more complicated,showing more random effects.