Analysis of hydrological drought characteristics using copula function approach

Analysis of hydrological drought characteristics using copula function approach

Drought is a natural phenomenon which starts with decreased precipitation and can disrupt the environmental systems by changing the hydrological cycle. This is more conspicuous in hydrological drought. In analysis of hydrological drought, two factors of severity (intensity) and duration play eminent...

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Bibliographic Details
Published in:Paddy and water environment Vol. 16; no. 1; pp. 153 - 161
Main Authors: Vaziri, Hamidreza, Karami, Hojat, Mousavi, Sayed-Farhad, Hadiani, Miromid
Format: Journal Article
Language:English
Published: Tokyo Springer Japan 2018
Springer Nature B.V
Subjects:
Agriculture
Analysis
Biomedical and Life Sciences
Bivariate analysis
Conditional probability
Distribution
Drought
Duration
Ecotoxicology
Evaluation
Flow index
Geoecology/Natural Processes
Goodness of fit
Hydrogeology
Hydrologic cycle
Hydrological cycle
Hydrology
Hydrology/Water Resources
Life Sciences
Low flow
Probability distribution
Probability theory
Rivers
Soil Science & Conservation
Statistical analysis
Statistics
Drought duration
Drought severity
Goodness-of-fit test
Low-flow index
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Summary:Drought is a natural phenomenon which starts with decreased precipitation and can disrupt the environmental systems by changing the hydrological cycle. This is more conspicuous in hydrological drought. In analysis of hydrological drought, two factors of severity (intensity) and duration play eminent role. These characteristics are highly related and therefore their combined analysis contributes to better understanding of the drought situation. In this research, by using 40-year (1974–2014) daily discharge data of Tajan River, located in Mazandaran province, Iran, and low-flow indices, the best evaluation index of hydrological drought was determined and 10 past hydrological drought events in the region were identified. Then, the best statistical distribution of both drought variables (duration and severity) was selected, based on the goodness-of-fit tests. Five copula functions were fitted to the data. Results showed that Galambos function with the highest maximum log-likelihood (− 8.934) was selected as the best copula function. Results of the bivariate (duration and severity) statistical distribution could be used to analyze the probability of hydrological drought in the region. This bivariate and conditional probability for the worst drought, with duration of 5 months and severity of 0.32, was 6.1 and 28.5%, respectively.
ISSN:1611-2490
1611-2504
DOI:10.1007/s10333-017-0626-7