Abstract
Drought is a complex natural disaster phenomenon. It is of great significance to analyze the occurrence and development of drought events for drought prevention. In this study, two drought characteristic variables (the drought duration and severity) were extracted by using the Theory of Runs based on four drought indexes (i.e., the percentage of precipitation anomaly, the standardized precipitation index, the standardized precipitation evapotranspiration index and the improved comprehensive meteorological drought index). The joint distribution model of drought characteristic variables was built based on four types of Archimedean copulas. The joint cumulative probability and the joint return period of drought events were analyzed and the relationship between the drought characteristics and the actual crop drought reduction area was also studied. The results showed that: (1) The area of the slight drought and the extreme drought were both the zonal increasing distribution from northeast to southwest in Yunnan Province from 1960 to 2015. The area of the high frequency middle drought was mainly distributed in Huize and Zhanyi in Northeast Yunnan, Kunming in Central Yunnan and some areas of Southwest Yunnan, whereas the severe drought was mainly occurred in Deqin, Gongshan and Zhongdian in Northwest Yunnan; (2) The drought duration and severity were fitted the Weibull and Gamma distribution, respectively and the Frank copula function was the optimal joint distribution function. The Drought events were mostly short duration and high severity, long duration and low severity and short duration and low severity. The joint cumulative probability and joint return period were increased with the increase of drought duration and severity; (3) The error range between the theoretical return period and the actual was 0.1–0.4 a. The year of the agricultural disaster can be accurately reflected by the combined return period in Yunnan Province. The research can provide guidelines for the agricultural management in the drought area.
Highlights
IntroductionDrought is a natural phenomenon of water shortage in the process of water circulation [1]
Drought is a natural phenomenon of water shortage in the process of water circulation [1].The process of drought occurrence is complex, progressive and has a widespread influence
In the winter and spring, standardized precipitation index (SPI) was most suitable in Northwest and Northeast Yunnan, SPI and precipitation anomaly (Pa) were recommended in Central Yunnan, Pa was more applicable in Southwest Yunnan and CInew had better monitoring effect in Southeast Yunnan
Summary
Drought is a natural phenomenon of water shortage in the process of water circulation [1]. The process of drought occurrence is complex, progressive and has a widespread influence. It will lead to crop yield loss, food shortage and environment degradation, which can cause great destruction to the economic and life [2,3,4]. The global surface temperature has increased about 0.85 degrees from. 1880–2012, and the future temperature would continue to rise in the fifth assessment report of the. Res. Public Health 2020, 17, 4654; doi:10.3390/ijerph17134654 www.mdpi.com/journal/ijerph
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