随机模拟方法在地区干旱频率分析中的应用

地区干旱历时和干旱程度等特征量的频率特性分析是区域水安全管理的重要基础工作，目前适用的分析方法主要是随机模拟技术，其中的关键问题是建立合适的降雨过程随机模型。考虑到实测降雨序列本身就包含有降雨的地区特性、连续时段雨量的变化特性等重要信息，以随机分析原理和计算机数值模拟为基础，对年降雨量过程进行统计特性分析，建立了面向实用性的P-Ⅲ型分布All（1）模型并通过了检验。应用结果表明，所建立的模型较为满意。该模型可用于生成大量的年降雨量模拟序列作为地区干旱指标序列，从而可对所研究地区干旱特征量的频率特性进行估计，对已发生的历史干旱事件的重现期进行识别。图2，表2，参8。

Application of Stochastic Simulation Technique to Frequency Analysis of Regional Drought

Frequeney analysis of regional drought characteristic quantities such as drought duration and degree is an important element in regional water security management. Currently, its applicable analysis method is primarily stochastic simulation, and the key problem in the simulation is to build a suitable stochastic model of precipitation process. Under consideration of the observed precipitation series containing much important information such as the temporal and regional characteristic of precipitation, this paper deals with statistical characteristic of the annual precipitation probabilistic process using the stochastic analysis theories and the technique of computer numerical simulation. A stochastic model named first order antoregressive model with Pearson Type m distribution was proposed for the practical use. The diagnostic test of the model has been passed. The calculating results show that the model designed is quite satisfactory. A great lot of simulated annual precipitation series can be generated as regional drought indexes by using the model, and then the frequency analysis of regional drought characteristic quantifies can be done, the return periods of regional history drought events can be identified.