Drought risk assessment in China with different spatial scales
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ORIGINAL PAPER
Drought risk assessment in China with different spatial scales Baisha Weng 1 & Ping Zhang 2 & Sinuo Li 3
Received: 10 February 2015 / Accepted: 28 April 2015 # Saudi Society for Geosciences 2015
Abstract With the increasing impact of climate change and anthropogenic activities, drought happens in more areas with higher frequency. In this paper, we calculate the return period and the drought risk in China based on the monthly PDSI, the Palmer Drought Severity Index, data over 188 stations from 1901 to 2010. We use the theory of runs to identify the drought duration and severity. We adopt the kernel density estimation to obtain the marginal distribution function, and the Gumbel Copula function to obtain the joint distribution function. The results show that the return period of the joint distribution for the drought duration and severity can be regarded as the extreme condition of the return period of the marginal distribution for the single factor such as the drought duration or drought severity. Under the same drought severity, the return period of the joint distribution is increasing with the prolonging of the drought duration, and it approaches to the return period of the marginal distribution of the drought severity. Under the extreme drought situation, Haihe River Basin, Huaihe River Basin, Songliao River basin, and rivers in the northwest China have a higher drought risk in future 50 years. The drought risk value in China is increasing with the prolonging of predicting time. Keywords Copula function . Kernel density estimation . Return period . Drought risk * Baisha Weng [email protected] 1
State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing, China
2
China Renewable Energy Engineering Institute, Beijing, China
3
Hebei University of Engineering, Hebei, China
Introduction Drought is an extreme event in hydrologic cycle. The occurrences of drought events usually feature determinacy and randomness. With the increasing impact of climate change and anthropogenic activities, drought happens in more areas with higher frequency. Drought issue has become one of the major factors to affect sustainable economic and social development. Drought occurs frequently not only in the northern China with shortage of water resources but also in the southern China with relatively abundant water resources. In recent years, several extreme drought events happened frequently in southwest China and the middle and lower Yangtze River. The annual average affected areas (the areas that crop yields decreased by over 10 % than normal annual yields) and damaged areas (the areas that crop yields decreased by over 30 % than normal annual yields) of drought disasters were nearly 0.21 × 108 km2 and 0.10×108 km2 from 1950 to 2010, which were 2.19 times and 1.77 times of the impacts of flood disasters, respectively (State Flood Control and Drought Relief Headquarters 2010). Therefore, it is important to study on the possibilitie
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