The drought returns period is an important indicator used to evaluate the severity of drought. It is difficult to accurately estimate drought loss due to the delay of disaster information. For research on crop yield loss, the statistical survey of post-drought disaster is used. These methods contain many evaluation indexes and need a large amount of statistical data, and the reliability of the data greatly constrains the accuracy of the results. It is widely used in drought assessment because of its convenience in data acquisition, simple calculation, and clear physical significance.Ĭurrently, most drought disaster risk assessment methods evaluate drought from four aspects: hazard, exposure, vulnerability, and drought resistance. The precipitation anomaly percentage ( Pa) index could easily directly reflect the drought caused by abnormally reduced precipitation in Guizhou. Many scholars used meteorological drought indicators to characterize agricultural drought. Investigating agricultural drought risk has become the focus of scientific research. Drought has reduced China’s grain production by 16,159 million ha in the last 60 years. Agriculture was a direct and sensitive sector of meteorological drought. Among them, meteorological drought is the main cause of agricultural drought. According to the classification standard of the World Meteorological Organization, definitions of drought are clustered to four types: meteorological, agricultural, hydrological, and socio-economic. In order to grasp the overall situation of drought disaster risk and enhance the comprehensive ability of the whole society to prevent and resist drought disasters, a national drought disaster risk assessment was carried out according to the requirements of the Implementation plan of the First National Survey of Comprehensive Natural Disaster Risks in China (⟮2020⟯ No.
This study could provide scientific knowledge for drought resistance and reasonable mitigation programing for the security of the regional agricultural production and the sustainability of social and economic development.ĭrought disaster is one of the most frequent, severe natural disasters widespread on a year-to-year basis. The results were highly consistent with the historical drought in Zunyi City, which verified the validity of the model. Meanwhile, the drought disaster was most drastic in the eastern region, followed by the south, north, west, and central area. Crop loss rate caused by drought increased and the affected area expanded with the increase of drought return periods (5, 10, 20, 50, and 100 years) in temporal distribution. The average drought duration in each county was about 1.5 months, and the average drought severity was about 0.35 in spatial distribution. From 1956 to 2020, fewer droughts occurred in Zhengan and Wuchuan, and the most droughts took place in Fenggang, Meitan, and Yuqing. The results showed that the Gumbel-Hougaard copula function was suitable for the joint distribution of drought joint variables in Zunyi City. Combined with the Jensen model, the agricultural drought loss rate under different drought return periods in the target year (2020) was calculated and evaluated. A copula function was applied to establish the joint distribution model of characteristic variables, obtaining the drought frequency and drought return periods. The monthly precipitation data set of ground meteorological observation stations in Zunyi City from 1956 to 2020 was selected, and the drought characteristic variables were extracted by the coupled use of the precipitation anomaly percentage ( Pa) index and the theory of runs. This study takes Zunyi City as an example, which is the most typical city of karst landform development. Due to climate change, the regional agricultural drought risk assessment has always been the focus of the academic circle. Agricultural drought is the most serious natural disaster.
China is one of the regions with the most frequent drought disasters and serious social and economic losses.
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