| Cite this article: | 廖显薇,高峰,魏婷,等.基于Copula函数的松花江流域水文干旱频率分析[J].灌溉排水学报,0,():-. |
| LIAO Xianwei,GAO Feng,WEI Ting,et al.基于Copula函数的松花江流域水文干旱频率分析[J].灌溉排水学报,0,():-. |
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| Copula-based Analysis of Hydrologic Drought Frequency in Songhua River Basin |
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LIAO Xianwei1, GAO Feng2, WEI Ting1, SONG Xiaoyan1, SONG Songbai1
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1.College of Water Resources and Architectural Engineering,Northwest A F University;2.Inner Mongolia Water Conservancy Research Institute
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| Abstract: |
| Abstract: 【Background】The occurrence of hydrological drought will have a significant impact on the water resources system of the Songhua River . Studying the frequency and uncertainty of hydrological drought is of great significance to water resources planning and drought resistance. Since univariate analysis cannot describe drought events objectively and comprehensively, it is inevitable to use Copula for multivariate analysis.【Objective】This paper analyzed the frequency of hydrological drought based on Copula in Songhua River Basin.【Method】The drought duration and severity of daily scale hydrological drought events were identified by using the Variable Threshold level Method and pooled them; The drought characteristic variables were fitted by six common distribution functions and evaluated the fitting degrees by Kolmogorov Smirnov test method. Selecting a function model from the three Copula functions, established a two-dimension joint distribution of drought characteristic variables and calculated the joint distribution probability and return period. Then, the uncertainty of drought research based on Copula was discussed by Monte Carlo method.【Result】The pooling criterion sets to pc =0.1 and tc=5, and the average drought duration is 81～105 days in Songhua River Basin; The lognormal distribution can describe the marginal distribution of drought duration well in Dalai, Fuyu and Harbin stations, but the optimal distribution of drought severity in each station is different; The Frank Copula is the optimal model for the two-dimension joint distribution of droughts. In Songhua River Basin ,the return periods of most droughts are no more than 20 years；Under the condition that the co-occurrence period is 20 years, the maximum probability design values of Dalai, Fuyu, Harbin and Jiamusi hydrological stations show greater uncertainty.【Conclusion】The Copula function can well fit the joint distribution of hydrological drought characteristic variables in the Songhua River Basin, However, the impact of uncertainty should be considered. |
| Key words: hydrological drought;Copula function,;pooling of drought events; Songhua;River Basin |
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