一种基于水文模拟建立中小河流洪水气象风险等级指标的方法

A method for defining flood meteorological risk indices of intermediate rivers based on hydrological simulation

提出一种基于水文模拟建立中小河流洪水气象风险等级临界累积面雨量指标(简称气象风险等级指标)的方法,由水位-流量曲线估计不同风险等级相应的临界参考流量,将2009年5月1日—9月30日綦江五岔、东溪、石角水文站的08:00BST报汛流量和雷达联合地面雨量计估测的流域面雨量作为TOPMODEL降水-径流模型率定时的流量和降水输入;在TOPMODEL水文模拟的基础上,选取2009年峰值流量过程,设计不同的小时面雨量序列进行水文模拟,得到峰值流量与流域累积面雨量的关系,根据临界参考流量,建立不同气象风险等级的临界累积面雨量指标;用2010年相应流域洪峰过程对所建立的指标进行检验。结果表明,利用气象风险等级指标推断的风险等级与实际洪峰对应的风险等级较为一致。

A method to define the flood meteorological risk rain threshold indices of intermediate rivers is presented based on hydrological simulation.Critical reference discharges for different flood meteorological risk grades are estimated with the stage-discharge curves.The 08： 00BST discharge data from the three hydrometric stations located respectively in Wucha（5 566 km2）,Dongxi（3 097 km2） and Shijiao（707 km2） of Qijiang and hourly mean areal precipitation（MAP） estimated with weather radar and rain gauges from 1 May to 30 September 2009 were taken as discharge and precipitation inputs of the TOPMODEL（TOPography based hydrological MODEL）.On the base of TOPMODEL hydrometric simulation,the hydrometric simulation was conducted using both the selected peak discharge processes in 2009 and designed different hourly MAP series.The relation between peak charge and accumulated MAP was obtained.According to the critical reference discharges the flood meteorological risk indices for intermediate rivers was defined.The defined flood meteorological risk indices was verified with the peak discharge processes of 2010 and results of the verification showed that the flood meteorological risk grades inferred from the risk rain threshold indices were consistent with the flood risk grades of observed flood peaks.