Calculation method of mountain torrent disaster probability rain pattern based on copula function

Abstract

The present invention discloses a method for deriving rain pattern of mountain torrent disaster probability based on copula function, comprising the steps of: collecting rainfall data of typical small watershed with small watershed as a unit; determining the position coefficient function of rain peak; using copula function to determine the combination of peak rain intensity and total rainfall Distribution function and solve it; determine the rain pattern under a certain probability. This method fully considers the randomness and uncertainty of the rainfall process. By collecting and arranging rainfall data in typical small watersheds, the joint distribution function of peak rainfall intensity and total rainfall based on the copula function is used, combined with the function of the location of the rain peak, to fully consider the rainfall The influence of the uncertainty of the peak position, peak rainfall intensity, and total rainfall together determine the characteristics of the rainstorm pattern under different probabilities in the small watershed in the study area. This method considers the influence of key factors on the uncertainty of rain patterns in the process of rain pattern determination, and provides a basis and reference for the study of rain pattern determination with different probabilities in small watersheds in hilly areas.

Description

technical field [0001] The invention belongs to the technical field of mountain torrent disaster research, in particular to a method for calculating the rain pattern of mountain torrent disaster probability based on a copula function. Background technique [0002] Affected by global climate change, the frequency and intensity of extreme rainstorm weather events have gradually increased, and the global or local precipitation structure has undergone significant changes, resulting in changes in the water vapor cycle, which have triggered a series of meteorological disasters. In recent decades, the intensity and frequency of extreme rainstorms in China have gradually increased, resulting in severe torrent disasters in small watersheds in my country, which have had a serious impact on human life, social development and natural ecosystems. [0003] Extreme torrential rain is caused by the uncertainty of the temporal and spatial distribution of rainfall. Rainfall is the key input d...

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Problems solved by technology

For example: Although the p&c method considers a certain probability distribution, it only places the rain peak at the most likely position, and does not consider other rain peak positions.

Moreover, the distribution ratio in the rest of the time periods is biased towards extremes, resulting in steep fluctuations in the rainfall process, which do not conform to the actual rainfall process; the huff rain type is based on the specific time period of the maximum rainfall intensity, and it is dimensionless with different frequencies. In the process of time allocation, the allocation of rainfall time history with different probabilities is calculated, but this method only divides the location of the maximum rainfall intensity into four types according to the duration of rainfall, without considering the randomness of the location of the rain peak; when the triangle rain pattern and the Chicago rain pattern are applied The position of the rain peak is fixed and the random probability distribution is not considered. Although a simple boundary is applied, it does not satisfy the randomness and uncertainty of the rainfall process, and it is easy to have a large discrepancy with the actual rainfall process, and the Chicago rain pattern cannot be used for more than 2 hours The distribution of rainfall time history does not meet the torrential rain characteristics of small watershed mountain torrent disasters

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