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Droughts are increasing in frequency and intensity as the global climate changes. Risk assessment for agricultural drought disasters is an important approach for disaster prevention and mitigation. Based on the formation mechanism of natural disaster risk, the index system model of agricultural drought risk assessment in North China was constructed, and the robustness of the established risk assessment model was tested by using the internal test method. Then based on the characteristics of agricultural drought risk formation in North China, the paper proposes corresponding risk prevention recommendations. The conclusions were as follows: when adjusting the indices and methods in the risk assessment model, the range of changes in the agricultural drought risk ranking for each city was mostly 1-2.5 places, and the model was relatively robust. With the exception of Beijing and Tianjin, which had the highest disaster prevention and mitigation capacity, central and northern China had the highest agricultural drought risk, which was previously linked to the high risk and vulnerability of these regions. The agricultural drought risk in northern Henan and southern Shandong is low, mainly due to the low risk. The 34 cities in North China can be divided into 6 agricultural drought risk clusters, which are not dispersed in space and cross-city distribution, and have good aggregation. Cluster 4, located in the northernmost mountainous areas, has the highest risk of drought, which is associated with high environmental vulnerability and low capacity for disaster prevention and mitigation, so agricultural areas should be reduced and agricultural input should be increased. Clusters 2, 5 and 6, located in the central and southern regions, have higher grain acreage and yields due to drought, so agricultural drought risk can be further reduced by increasing agricultural input and improving irrigation guarantee rate. [ABSTRACT FROM AUTHOR]

Arid area is very sensitive to global warming and are extremely vulnerable to climate change. Moreover, the water resources system in the arid area is fragile and will undergo tremendous changes with climate change. Therefore, the interaction of climate and hydrology in arid area has an important impact on the formation of regional microclimate and hydrological changes. Daihai Lake is a typical closed inland lake in arid area of China, and a key area for ecological protection in North China. In this paper, WRF-Hydro model is used to simulate the climate hydrological coupling situation of Daihai Basin from 1980 to 2020, and the coupling results are verified and calibrated by meteorological statistics, runoff calculation and remote sensing analysis. Based on the synopsis of climate and hydrology in the past 40 years, the causes and future trends of the hydrological elements in Daihai Basin are analyzed. Through the analysis, it is found that the interannual variation of precipitation in Daihai Basin is sharp, with 401.75 mm as the average from 1980 to 1994; and drastic fluctuations from 1995 to 2011, with a difference of nearly 400 mm between the interannual maximum and minimum; From 2012 to 2020, the fluctuation is small. Although the interannual variation of evaporation fluctuated, it showed an upward trend with a slope of 8.855 mm/year. The annual average temperature showed an obvious upward trend with a slope of 0.040 °C/year. From 1980 to 2020, the inflow of Daihai Lake shows a downward trend; Since 2013, the runoff into the lake has tended to be flat. Climate change and human activities are the decisive factors leading to the change of water quantity in Daihai, among which human activities play a greater role. Cultivated land irrigation and industrial water use are highly correlated with the lake discharge, and these two factors have a great influence on the lake discharge. If the current agricultural and industrial water consumption does not increase, Daihai still has a lifespan of nearly 120 years. If human activities do not change and any protective measures are not taken in time, under the background of global climate change, the flow of the Daihai Lake into the lake will be reduced to zero in 2025, and the Daihai Lake will completely dry up in 2031–2033. The study of climate hydrological coupling of long time series in Daihai Basin can not only make up for the lack of runoff data, but also provide the basis for water resources management, disaster prevention and mitigation. [ABSTRACT FROM AUTHOR]

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Climate elements are important indicators of climate change in China's main grain-producing areas during the April–September growth season and affect the growth and yield of crops. This paper combines grain concentration and geographical detector to divide the North and South regions of China's main grain production. The linear trend and Morlet wavelet transform methods are used to analyse the characteristics of climate change based on observational climate data from April to September 1981–2015. The results show that the climate in the North region is warm and dry during the growth season, whereas the climate is warm and humid in the South region. The main periods of the change in temperature in the North and South regions are 3 years, and that in precipitation is 5 years, and that in sunshine hours is 3–4 years. Changes in the climate elements in various provinces show complex, varying and regional characteristics of cold-warm and dry-wet cycles. The changes in climate elements are significant and different climatic conditions and regions have various possible impacts on grain production in China during the growth season. For China's agricultural-economy sustainable development and grain security, the study suggests that governments should place more emphasis on climatic element changes during the growth season and invest more money in disaster prevention and mitigation, especially in the main grain-producing areas. [ABSTRACT FROM AUTHOR]

The enormous losses caused by typhoon storm surges in coastal areas highlight the importance of assessing direct economic losses induced by typhoon storm surges. It is assumed that the trend of losses is mainly caused by the change in storm intensity resulting from climate change and the exposure and vulnerability of socioeconomic levels. This study constructed a hazard dataset of typhoon storm surges covering zero-loss events in mainland China from 1989 to 2019. Following the annual data trend analysis, the improved elasticity estimation model was used innovatively to assess and attribute the occurrence and the amount of typhoon storm surge-induced direct economic losses. The results show that the risks of typhoon storm surge are more sensitive to changes in climate-induced hazard intensity factors than socioeconomic factors. A 1% increase in minimum pressure decreases the hazard occurrence probability ratio by nearly 130% and disaster losses by approximately 47%, while a 1% increase in gross domestic product per capita increases the ratio by 1.4% and decreases losses by approximately 0.98%. A 1% increase in population density would increase the ratio by 0.97% and disaster losses by 0.63%. However, the rapid socioeconomic development of the typhoon storm surge-affected area is the main factor for the loss trend during the study interval. Wealth increments and population concentrations in coastal areas have contributed to the increasing possibility of loss occurrence. The growth in wealth has also contributed to the improvement of disaster risk management and the reduction of the loss amount. This study clarifies the quantitative relationship between typhoon storm surge risk (the occurrence and the amount of losses) and physical and socioeconomic drivers, and highlights how socioeconomic dimensions contribute to storm surge losses. The model can be used for risk predictions given the considerations for climate change and future socioeconomic development in coastal regions of China and can be further applied to risk management and disaster prevention and mitigation of storm surges. [ABSTRACT FROM AUTHOR]

The evolution of the frequency of dry/wet spells is a hot topic in global climate change research. The synergistic effects of dry/wet spells make their consequences far more significant than a single disaster, having considerable impacts on hydrology, ecology, and economies, especially in the context of global warming. In this study, the standardized precipitation evapotranspiration index (SPEI)‐based identification of dry/wet spells was used to explore the evolution of the frequency of dry/wet abrupt alternation (DWAA) events in the past four decades in China, makes up for the lack of research on the evolution of such compound disasters. China has been affected by dry/wet spells in many areas for a long time. Studies found that high‐frequency DWAA areas are concentrated in densely populated areas, China's essential food bases and core areas for economic development. Dry‐to‐wet (D–W) events and wet‐to‐dry (W–D) events basically increased or decreased at the same pace in this period. We innovatively find DWAA events (D–W events and W–D events) are projected to occur increasingly in a wider region of China. The frequency of D–W events across China has increased from 2.35 in the 1980s to 3.56 in the last decade, a 50% increase. On the other hand, W–D events increased from 2.6 to 3.23, increasing 24%. The three regions with the most remarkable changes in the past four decades are Inner Mongolia, northwest China, and north China, where D–W events increased by 121, 61, and 58%, respectively, and W–D events increased by 71, 57, and 61%, respectively. Hereby, it is vital to implement effective prevention against DWAA events in the area which has been neglected in the past decades because of lower frequency. These results may help policymakers develop suitable disaster mitigation plans for reducing the potential risks of extreme compound natural events. [ABSTRACT FROM AUTHOR]

AbstractClimate elements are important indicators of climate change in China's main grainproducing areas during the April–September growth season and affect the growth and yield of crops. This paper combines grain concentration and geographical detector to divide the North and South regions of China's main grain production. The linear trend and Morlet wavelet transform methods are used to analyse the characteristics of climate change based on observational climate data from April to September 1981–2015. The results show that the climate in the North region is warm and dry during the growth season, whereas the climate is warm and humid in the South region. The main periods of the change in temperature in the North and South regions are 3 years, and that in precipitation is 5 years, and that in sunshine hours is 3-4 years. Changes in the climate elements in various provinces show complex, varying and regional characteristics of cold-warm and dry-wet cycles. The changes in climate elements are significant and different climatic conditions and regions have variouspossible impacts on grain production in China during the growth season. For China's agricultural-economy sustainable development and grain security, the study suggests that governments should place more emphasis on climatic elements changes during the growth season, and invest more money in disaster prevention and mitigation, especially in the main grain producing areas.Key words: grain-producing regions; changes in climate elements; growth season; climate trend50 coefficient; climate tendency rate; wavelet analysis [ABSTRACT FROM AUTHOR]

Climate change causes drought and rainstorm, two extreme hydrological events, to occur interlock, and in a short period of time the rapid transformation of drought and flood disasters, resulting in more difficult rescue and relief, agricultural losses more serious. In order to study the characteristics of drought and flood in tobacco growing period in Xingren County. By defining the Long-cycle Drought-Flood Abrupt Alternation Index (LDFAI) and Short-cycle Drought-Flood Abrupt Alternation Index (SDFAI), the moving average method and precipitation anomaly are used. For the daily precipitation data during the tobacco growth period (5~8 months) from 1961 to 2012 in Xingren County, A comprehensive analysis of the (LDFAI SDFAI) change trends and monthly precipitation changes during the growth period of tobacco. The characteristics of rapid change of drought and flood in tobacco growing period were identified. The results showed that: the LDFAI in the tobacco growth period are mainly from drought to flood. In the future, there will be an increasing trend from flood to drought, and the strength is reduced; The trend of SDFAI is: increase-decrease-decrease; there is an increasing trend from drought to flood events in May-June; June-July is a period of drought-flood abrupt alternation, and the intensity is higher. In July-August, the flood to drought event has a decreasing trend and the intensity is reduced. During the tobacco maturity period, Monthly average precipitation is higher, the precipitation fluctuates greatly, Extremely prone to Drought-Flood Abrupt Alternation. The research results can provide theoretical basis for the formulation of countermeasures for disaster prevention and mitigation in Xingren County in China. [ABSTRACT FROM AUTHOR]