A stochastic analysis of extreme droughts
A stochastic analysis of extreme droughts
复制标题
极端干旱的随机分析
DOI：
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发表时间：
1975
期刊：
影响因子：
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通讯作者：
L. Duckstein
中科院分区：
文献类型：
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作者：
V. Gupta;L. Duckstein
本文对一次点降雨过程的最大干间隔时间--极端干旱持续时间进行了随机分析。先前的分析所依据的假设被推广到一个非齐次泊松过程。分析结果，这似乎是棘手的一般，推导出两个特定形式的强度函数的泊松过程;对于一般的强度函数，模拟建议。其次，小的时间间隔，如作物的生长季节被认为是一个均匀的泊松降雨过程的假设，可以作出和参数估计的理论结果的效果可以定性研究。为了说明这一点，强度参数的四个估计计算通过使用降水数据从芝加哥和奥斯汀。一个很好的协议之间的理论和经验的分布函数的两个参数估计值计算通过使用在本次调查中开发的模型，另一方面，一个实质性的偏差是直接从数据计算的参数。最后，一种方法是示意性地表示，通过使用随机叠加模型扩展到区域干旱。
A stochastic analysis is performed on the extreme drought duration defined to be the maximum dry interval for a point rainfall process. The assumptions underlying previous analyses are generalized to those of a nonhomogeneous Poisson process. Analytical results, which seem intractable in general, are derived for two particular forms of the intensity function of the Poisson process; for a general intensity function, simulation is recommended. Next, small time intervals such as the growing season of a crop are considered so that the assumption of a homogeneous Poisson rainfall process may be made and the effect of parameter estimation on the theoretical results may be studied qualitatively. To illustrate this point, four estimates of the intensity parameter are calculated by using precipitation data from Chicago and Austin. A good agreement is found between the theoretical and empirical distribution functions for the two parameter estimates calculated by use of the model developed in this investigation; on the other hand, a substantial bias is present for parameters calculated directly from the data. Finally, an approach is schematically indicated to extend the model to regional droughts by using stochastic superposition.