暴雨分割技术SDOIF的改进

The Improvement of Storm Separation Technique SDOIF

分时段地形增强因子法(SDOIF)是适用于山区可能最大降水(PMP)估算的暴雨分割技术。为了探讨不同类型的极值降雨系列对山区地形增强因子估算成果的影响以及分析SDOIF的不确定性,基于香港71个站点历史雨量资料,应用地区线性矩法推求各站点不同重现期(100 a一遇、200 a一遇和500 a一遇)的24 h降雨频率估计值,比较24 h年最大降雨系列和同时段的降雨稀遇频率估计值对定量推求香港地区平均地形增强因子的影响。研究结果表明,采用降雨稀遇频率估计值系列,譬如100 a一遇,能够更稳定和合理地估算地形增强因子的空间分布。另外,基准雨量站的选择会在一定程度上影响地形增强因子的估算成果,所以使用SDOIF时需要有足够的资料和对研究地区进行充分的调查。

SDOIF（ step duration orographic intensification factor method） has been recommended as a useful rainstorm separation method for the probable maximum precipitation（ PMP） estimation in mountainous areas. In order to investigate the variation of orographic intensification factors（ OIF） with different categories of extreme rainfall in mountainous areas as well as the uncertainties of the SDOIF,based on Hong Kong＇s historical 24 h annual maximum precipitation data of 71 stations,the Regional L-moments analysis is used to estimate the quantiles of different return periods（ 100-year,200-year,500-year） at 71 rainfall stations. Then Hong Kong ＇s average OIF calculated based on the annual maximum precipitation and the quantiles of different return period are compared. The results show that by using the quantiles of 100-year return period to estimate the OIF is more stable and reasonable in spatial distribution. In addition,the study indicates that the selection of basic rainfall stations will affect the outcome of the OIF stimates to some extent,therefore adequate data and cautious investigation are required in the application of the SDOIF method.