Page 130 - 2021年第52卷第10期

Probability distribution of daily precipitation in China

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GU Xuezhi ，YE Lei ，ZHAO Tongtiegang ，OUYANG Wenyu ，ZHANG Chi
（1. College of Hydraulic Engineering，Dalian University of Technology，Dalian 116024，China；
2. College of Civil Engineering，Sun Yat-sen University，Zhuhai 519082，China）

Abstract： In view of the fact that there is no universal suitable daily precipitation probability distribution
in China， the daily precipitation data measured by 820 meteorological stations in China were taken as the
research object. According to the L-moment diagram， seven potential probability distributions were selected
for fitting the daily precipitation data. Root mean square error was selected to evaluate the goodness of fit，
and the distributions of KAP and P-Ⅲ were preliminarily determined to be the most suitable in the whole
country. Then the selection strategy of optimal distribution was further formulated. For the stations with simi⁃
lar fitting effect of KAP and P-Ⅲ ， Monte Carlo simulation based on weather generator was carried out to
evaluate the ability of these two distributions to simulate different quantiles and the interannual fluctuation
of precipitation series. Then the spatial distribution maps of optimal probability distribution in climate，geog⁃
raphy and watershed zones of China were drawn. The results show that：KAP has a wider area of applica⁃
tion， and the ability to simulate the whole frequency range of precipitation is stronger； P-Ⅲ has three to
four obvious concentrated areas as the optimal distribution；and G2 which is generally accepted is not suit⁃
able for wide use because of poor fitting effect. Researchers can determine the optimal daily precipitation
probability distribution according to the results of this paper and combining with the research purposes and
application requirements，so as to minimize the deviation caused by improper selection of probability model.
Keywords： daily precipitation； optimal probability distribution； linear moment； weather generator； Monte
Carlo simulation；KAP distribution；P-Ⅲ distribution

（责任编辑：杨 虹）

（上接第 1247 页）

The layout shape and effect of dentated bucket on overflow outlet in high arch dam

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SUN Shuangke ，XU Jianrong ，LIU Haitao ，PENG Yu ，XUE Yang 2
（1. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin，China Institute if Water Resources and Hydropower
Research，Beijing 100038，China；2. Huadong Engineering Corporation Limited，Hangzhou 311122，China）
Abstract：It is a competitive technical measure to optimize the shape of high arch dam by setting dentated
buckets on the overflow outlet，which can disperse the water tongue energy and reduce the impact pressure
on the bottom of the downstream water cushion pond. This paper introduces an integral hydraulic model
test of Baiheta hydropower station， in which there are 6 overflow outlets and 7 deep outlets， studying on
the overflow outlet dentated bucket layout method， detail structure shape and its effect. The study shows
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that for this project，1 overflow outlet using lateral unilateral dentated bucket，4 overflow outlet with dou⁃
ble side dentated bucket arrangement method，can effectively reduce the impact pressure of the bottom
plate. Further experimental study to the dentated bucket width and pick angle found that the width of a sin⁃
gle dentated bucket on overflow outlet is 0.18-0.23 times of the width of the front，and the pick angle is
15-20 degrees， which is the best detail structure parameters. The above research results can be used as
reference for similar projects.
Keywords：dentated bucket；overflow outlet；energy dissipation；floor of plunge pool；the impact pressure

（责任编辑：韩 昆）

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