| Autor: |
LIAO Xianwei, GAO Feng, WEI Ting, SONG Xiaoyan, SONG Songbai |
| Jazyk: |
čínština |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
Guan'gai paishui xuebao, Vol 40, Iss 3, Pp 134-141 (2021) |
| Druh dokumentu: |
article |
| ISSN: |
1672-3317 |
| DOI: |
10.13522/j.cnki.ggps.2020330 |
| Popis: |
【Background】 Drought could significantly impact hydrological processes and water resources, and understanding frequency and uncertainty of drought occurrence is hence imperative to water resources planning. The copula method has emerged as an improved multivariate analysis over the univariate analysis for quantitative analysis of drought. 【Objective】 This paper is to present the results of the frequency and severity of droughts in Songhua river basin calculated using the copula multivariate method. 【Method】 The analysis was based on archived data, and duration and severity of the pooled daily drought events were identified using the variable threshold level method. The drought index variables were fitted by six common distribution functions respectively, and they were then evaluated using the Kolmogorov Smirnov test method. Optimal model selected from three Copula functions was used to establish a two-dimensional joint distribution for the drought index variables, from which we calculated the joint distribution probability as well as the return period. The uncertainty of the drought was analyzed using the Monte Carlo method. 【Result】 With the pooling criteria set to be pc=0.1 and tc=5, the average drought duration was 81~105 days in the basin. The lognormal distribution can adequately describe the marginal distribution of the drought duration in Dalai, Fuyu and Harbin stations in the basin, despite the differences in optimal distribution of the drought severity between them. The Frank copula was the best model for the two-dimensional joint distribution of the drought, and the return periods of the droughts were less than 20 years. When the return period was 20 years, the maximum design values for Dalai, Fuyu, Harbin and Jiamusi hydrological stations were most uncertain. 【Conclusion】 The copula multivariate model can adequately describe the joint distribution of the drought index variables in Songhua river basin, and its application should consider drought uncertainty. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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