| Analysis of agricultural meteorological drought disaster around western Liaoning Province based on Copula function |
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| DOI：10.7606/j.issn.1000-7601.2018.02.40 |
| Key Words: agricultural meteorological drought SPI Copula function return period Western Liaoning Province |
| Author Name | Affiliation | | LI Ying | School of urban and Environmental Sciences, Liaoning Normal University, Dalian, Liaoning 116029, China | | FENG Yu | School of urban and Environmental Sciences, Liaoning Normal University, Dalian, Liaoning 116029, China | | TANG Wei-nan | School of urban and Environmental Sciences, Liaoning Normal University, Dalian, Liaoning 116029, China | | REN Jia-xuan | School of urban and Environmental Sciences, Liaoning Normal University, Dalian, Liaoning 116029, China |
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| Abstract: |
| Drought is one of the frequent natural disasters of the western part of Liaoning province, and its impaction on the agriculture is very significant. Considering many elements of meteorological drought effect, in this paper, the duration and intensity of agro-meteorological drought in western Liaoning in 1956—2014 were extracted by using the run-length theory based on SPI index. On the basis of determining the univariate edge distribution, the Copula function was used to analyze the joint probability and return period of drought occurrence. Based on the actual situation of crop drought from 1991 to 2011, the relationship between the drought recovery period and crop drought loss was discussed. The results showed that: (1) the correlation between the drought duration and drought intensity was large, conformed to the Weibull distribution and Generalized Extreme Value distribution respectively, and Frank-Copula function was suitable for simulation of the drought duration and intensity jointed distribution; (2) This area has higher probability of occurrence of drought with both low duration and intensity, short duration and high intensity, and long duration but low intensity. (3) the return period in western Liaoning was relatively short under the combination of high intensity short duration and low intensity long duration, which shows that the western Liaoning was more of light, moderate drought, and return period in most cases was 2～4 months; (4) The actual return period of 1991—2011 was close to that of the theory, which indicates that the joint return period can better reflect the frequency of disaster; (5) The return period of mild drought was less than 2 months, 8 months or more severe drought, 2～8 months to moderate drought. This classification of the drought event can provide a targeted policy for the Agricultural sector to solve the problem of drought disaster. |
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