Urban design storm rainfall pattern calculation method

Abstract

The invention discloses an urban design rainstorm rainfall pattern calculation method. Firstly, a rainstorm is sampled, and a rainstorm sample is determined; then the rainstorm sample is divided into a pre-peak rainstorm sample and a post-peak rainstorm sample according to the position where the maximum rainfall is located; rainfall peak coefficient of the rainstorm sample and the rainfall proportion of the pre-peak rainstorm sample in the total rainfall of the rainstorm sample are calculated based on the dividing result of the pre-peak rainstorm sample and the post-peak rainstorm sample, and a pre-peak rainstorm rainfall pattern and a post-peak rainstorm rainfall pattern are respectively calculated based on a Huff rainfall pattern method according to the time distribution characteristics of the pre-peak rainstorm sample and the post-peak rainstorm sample; the re-peak rainstorm rainfall pattern and the post-peak rainstorm rainfall pattern are merged, an urban design storm rainfall pattern is obtained. By adopting the method, the inconsistency of rainfall laws of the designed rainstorm before and after a rainfall peak is fully considered, the obtained designed rainfall pattern has high matching degree with the actual precipitation process, and the defect that the calculated rainfall pattern is greatly different from the actual precipitation process due to the fact that diachronic change of the rainfall peak position is not considered in a traditional method is overcome.

Description

technical field [0001] The invention belongs to the technical field of urban design rainstorm research, and more particularly relates to a derivation method for urban design rainstorm patterns. Background technique [0002] While urbanization promotes social and economic development, it also has a negative impact on the natural ecological environment of urbanized areas. Urbanization makes urban areas have a greater heat absorption rate, forming the "heat island effect". In addition, urbanization brings a large number of condensation nuclei that are conducive to precipitation and the disturbance of buildings on airflow, forming the "rain island effect". Changes in the precipitation characteristics of urbanized areas, under the background of global warming, extreme rainstorm weather events increased significantly. [0003] The rainfall process has the characteristics of uneven temporal and spatial distribution. The rain pattern of urban design rainstorm refers to the distribu...

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Problems solved by technology

[0004] 1. The Keifer&Chu rain pattern, Pilgrim&Cordery rain pattern, and Huff rain pattern did not consider the influence of the difference in the actual rainfall process before and after the rain peak on the derivation of the urban design rainstorm pattern; however, the actual rainfall process has time distribution inhomogeneity. It is different from the change pattern of rainfall after the rain peak;

[0005] 2. The urban design rainstorm process and its rain peak position deduced by Keifer&Chu rain pattern method are definite, which is quite different from the actual rainfall process. When using it to simulate the urban rainfall runoff process, the peak value of surface runoff will be underestimated and the peak time will be delayed. question

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