Using a stochastic model for generating hourly hyetographs to study extreme rainfalls
نویسندگان
چکیده
Abstract A stochastic model for generating hourly hyetographs has been developed using data from observed precipitation records to simulate rainfall patterns. This model makes it possible to study maximum precipitation distributions for normal or exceptional frequencies over long periods of time. The modelling provides observations (up to 10-year frequency) of quantiles similar to those observed by directly fitting a law of statistical distribution onto an observed distribution. Differences occur for rare frequency quantiles. Modelled rainfall frequency distributions behave in an over-exponential way (i.e. greater than strictly exponential) at infinity, yielding higher results than those obtained using standard fittings. One factor that is considered in modelling can explain this behaviour: the persistence of storms within a rainfall episode which causes high rainfall accumulation. Thus modelling the observed phenomenon provides an innovative approach in studying extreme occurrences.
منابع مشابه
A generalized super-efficiency model for ranking extreme efficient DMUs in stochastic DEA
In this current study a generalized super-efficiency model is first proposed for ranking extreme efficient decision making units (DMUs) in stochastic data envelopment analysis (DEA) and then, a deterministic (crisp) equivalent form of the stochastic generalized super-efficiency model is presented. It is shown that this deterministic model can be converted to a quadratic programming model. So fa...
متن کاملThe intrinsic dependence structure of peak, volume, duration, and average intensity of hyetographs and hydrographs
[1] The information contained in hyetographs and hydrographs is often synthesized by using key properties such as the peak or maximum value Xp , volume V, duration D, and average intensity I. These variables play a fundamental role in hydrologic engineering as they are used, for instance, to define design hyetographs and hydrographs as well as to model and simulate the rainfall and streamflow p...
متن کاملEvaluation of short term rainfall analysis methods (Case Study: Shahrekord station)
Determination of maximum rivers flow resulted from surface runoff in watersheds without adequate hydrometric records is based on rainfall-runoff models. The short duration rainfalls are one of the basic elements to apply these models. The access to quantitative and intrinsic worth storm data is restricted around the word and in Iran too. There are several empirical and statistical methods to es...
متن کاملDesigning Stochastic Cell Formation Problem Using Queuing Theory
This paper presents a new nonlinear mathematical model to solve a cell formation problem which assumes that processing time and inter-arrival time of parts are random variables. In this research, cells are defined as a queue system which will be optimized via queuing theory. In this queue system, each machine is assumed as a server and each part as a customer. The grouping of machines and parts...
متن کاملModelling extreme rainfalls using a modi®ed random pulse Bartlett±Lewis stochastic rainfall model (with uncertainty)
A modi®ed random pulse Bartlett±Lewis stochastic rainfall model is used for extreme rainfall simulation. The model features the use of a generalised pareto distribution (GPD) to represent the depths of high intensity raincells. A point rainfall record, obtained from a UK site is used to test the model. Parameter estimation is carried out using a two-stage approach based on the generalised likel...
متن کامل