Drought risk assessment in China:Evaluation framework and influencing factors

Global warming and rapid economic development have led to increased levels of disaster risk in China.Previous attempts at assessing drought risk were highly subjective in terms of assessment methods and selection of the assessment indicators and which resulted in appreciable uncertainty in the results of these risk assessments.Based on the assumption that areas with historically high drought losses are more likely to suffer future high drought losses,we develop a new drought risk assessment model that includes historical drought loss data.With this model,we map the regional differentiation of Chinese drought risk.Regions with high(extreme high)drought risk account for 4.3%of China’s area.Five significant high-risk areas have been identified:Northeast China,North China,the east part of Northwest China,the east part of Southwest China and a small part in the west of Northwest China.Areas with high and extreme high drought risk are dominant in the Heilongjiang Province,accounting for 32%of the total area,followed by the Ningxia Hui Autonomous Region,with 26%of total area.The contribution of each influencing factor has been quantified,which indicates that high-exposure and high-vulnerability account for the high-risk of drought.We recommend that measures like strengthening the protection of cultivated land and reducing dependence on the primary industry should be taken to mitigate to drought-induced losses.

Assessment on Agricultural Drought Risk Based on Variable Fuzzy Sets Model

Drought is one of the major natural disasters causing huge agricultural losses annually. Regional agricultural drought risk assessment has great significance for reducing regional disaster and agricultural drought losses. Based on the fuzzy characteristics of agricultural drought risk, variable fuzzy sets model was used for comprehensively assessing agricultural drought risk of Liaoning Province in China. A multi-layers and multi-indices assessment model was estab-lished according to variable fuzzy sets theory, and agricultural drought risk of all 14 prefecture-level cities was respec-tively estimated in terms of dangerousness, vulnerability, exposure and drought-resistibility. By calculating the combi-nation weights of four drought risk factors, agricultural drought risk grade of each city was obtained. Based on the as-sessment results, the spatial distribution maps of agricultural drought risk were drawn. The results shows that eastern cities have lower drought dangerousness than western cities in Liaoning Province totally. Most cities are located in low drought vulnerability region and high drought exposure region. Because of frequent and severe drought since 2000, most cities are located in lower drought-resistibility region. Comprehensive agricultural drought risk presents apparent spatial characteristics, escalating from the east to the west. Drought dangerousness is the most important factor influencing comprehensive agricultural drought risk. Through the spatial distribution maps of drought risk, decision makers could find out drought situation and make decisions on drought resistance conveniently.

Impacts of climate change on drought risk of winter wheat in the North China Plain

Drought is a major natural disaster causing crop yield losses,while its occurrence mechanism and spatiotemporal variations in a changing climate are still not clear.Based on a long-term climatic dataset(during 1958–2015)from weather stations in the North China Plain(NCP),the influencing mechanism of various climatic factors on drought risk of winter wheat was quantified by using sensitivity analysis,Mann-Kendall trend test and slope estimation.The results indicated that climatic factors have changed considerably over the past six decades in the growth season of winter wheat.As a result,winter wheat suffered from severe droughts(with 350 mm of water deficit during its growth season),particularly at the jointing–heading and heading–mature stages,which were critical to crop yield formation.There were large spatial and temporal variations in drought risk and climatic change factors at different growth stages of winter wheat.Despite precipitation playing a vital role in determining the spatiotemporal patterns of drought risk,high temperature and low humidity along with other climatic factors at key growth stages of winter wheat aggravated drought risk.Particularly,temperature at nearly 90%weather stations showed a notablely upward trend,which exacerbated water deficit and drought risk of winter wheat.Given the complexity and high uncertainty of climate change,these findings provide important information for adapting crop production to future climate change and accompanied droughts while ensuring food security and agricultural sustainability.

Risk assessment of maize drought disaster in southwest China using the Environmental Policy Integrated Climate model

The East Asian monsoon has a tremendous impact on agricultural production in China. An assessment of the risk of drought disaster in maize-producing regions is therefore important in ensuring a reduction in such disasters and an increase in food security. A risk assessment model, EPIC（Environmental Policy Integrated Climate） model, for maize drought disasters based on the Erosion Productivity Impact Calculator crop model is proposed for areas with the topographic characteristics of the mountainous karst region in southwest China. This region has one of the highest levels of environmental degradation in China. The results showed that the hazard risk level for the maize zone of southwest China is generally high. Most hazard index values were between 0.4 and 0.5,accounting for 47.32% of total study area. However,the risk level for drought loss was low. Most of the loss rate was ＆lt;0.1, accounting for 96.24% of the total study area. The three high-risk areas were mainlydistributed in the parallel ridge–valley areas in the east of Sichuan Province, the West Mountain area of Guizhou Province, and the south of Yunnan Province.These results provide a scientific basis and support for the reduction of agricultural drought disasters and an increase in food security in the southwest China maize zone.

Application of long-range correlation and multi-fractal analysis for the depiction of drought risk

By using the multi-fractal detrended fluctuation analysis method, we analyze the nonlinear property of drought in southwestern China. The results indicate that the occurrence of drought in southwestern China is multi-fractal and long- range correlated, and these properties are indifferent to timescales. A power-law decay distribution well describes the return interval of drought events and the auto-correlation. Furthermore, a drought risk exponent based on the multi-fractal property and the long-range correlation is presented. This risk exponent can give useful information about whether the drought may or may not occur in future, and provide a guidance function for preventing disasters and reducing damage.

Risk Assessment and Zoning of Winter Wheat Drought in Anhui Province

[Objective]The study aimed to assess and zone the drought risk of winter wheat in Anhui Province. [Method] The zoning factors were chosen from three aspects of disaster-causing factors,disaster-bearing bodies and environment conducive to drought,and then their data were standardized,rasterized and graded. Using analytic hierarchy process（ AHP）,we determined the weight of each index at various levels and then established the assessment models of drought intensity,sensitivity,vulnerability and resistance of winter wheat in the whole growth period and at heading and filling stage. Finally,the zoning map of drought risk for winter wheat in Anhui Province was obtained using the farmland data mask of Anhui Province. [Result]The drought risk of winter wheat in Anhui Province in the whole growth period and at heading and filling stage was divided into six grades,which reflected the distribution characteristics and regional difference of drought risk for winter wheat in Anhui Province. Drought risk was the maximum in the main producing areas of winter wheat in the north of Huaihe River,followed by the area along Huaihe River and the area between Yangtze River and Huaihe River,while the drought risk of winter wheat was very low in the south of Anhui Province. The drought risk of winter wheat was markedly affected by the sensitivity to drought,vulnerability and the drought resistance of winter wheat. [Conclusion] The research could provide scientific references for rational distribution of winter wheat and establishment of strategies for disaster prevention and mitigation.

Datasets of meteorological drought events and risks for the developing countries in Eurasia

For the area of Eurasia concentrated with developing countries(referred to here by the abbreviation DPEA),mainly located in Asia and Eastern Europe,this work presents datasets of gridded meteorological drought events and country-based drought risk by combining multiple drought indices and socio-economic data.A basic gridded dataset of the drought events during 1950-2015 is extracted from three drought indices:the self-calibrating Palmer Drought Severity Index,the Standardized Precipitation Index,and the Standardized Precipitation Evapotranspiration Index.The three drought indices generally show consistent characteristics of drought events in DPEA.A second-level dataset(a drought risk dataset)is then produced as the product of drought hazard,exposure and vulnerability during 2000-2015.For drought exposure,the indicators of population and livestock density,agricultural land and water stress are chosen,while drought vulnerability composites multiple social,economic and infrastructural factors.Drought hazard tends to concentrate at the southern rim of Eurasia.Relatively large differences in drought exposure exist between different countries,but for drought vulnerability the differences are small.After considering the socio-economic components in risk assessment,most countries in West,South-Central and South Asia have the highest drought risk in DPEA.The datasets of drought events and risks are available at http://www.dx.doi.org/10.11922/sciencedb.898.

Trends of Extreme Precipitation in Eastern China and Their Possible Causes

Significant increases of heavy precipitation and decreases of light precipitation have been reported over widespread regions of the globe. Global warming and effects of anthropogenic aerosols have both been proposed as possible causes of these changes. We examine data from urban and rural meteorological stations in eastern China （1955-2011） and compare them with Global Precipitation Climatology Project （GPCP） data （1979-2007） and reanalysis data in various latitude zones to study changes in precipitation extremes. Significant decreases in light precipitation and increases in heavy precipitation are found at both rural and urban stations, as well as low latitudes over the ocean, while total precipitation shows little change. Characteristics of these changes and changes in the equatorial zone and other latitudes suggest that global warming rather than aerosol effects is the primary cause of the changes. In eastern China, increases of annual total dry days （28 days） and ） 10 consecutive dry days （36%） are due to the decrease in light precipitation days, thereby establishing a causal link among global warming, changes in precipitation extremes, and higher meteorological risk of floods and droughts. Further, results derived from the GPCP data and reanalysis data suggest that the causal link exists over widespread regions of the globe.

Analysis of Hay Demand from Pastoralism Systems on Viability of Hay Production as a Climate Adaptation Strategy in Kajiado County, Kenya

Hay production is a flagship project under drought risk reduction and climate change adaptation programs in pastoralism livestock systems in Kenya. For decision-makers to plan and evaluate their projects, they need localized data on hay production and supply and to understand what attitudes influence demand for hay by pastoralists. A cost-benefit analysis on 23 hay farms and a questionnaire knowledge, attitude and practice survey on 340 pastoralists in Kajiado Central were undertaken. This study provides the hay production versus hay deficit figures in Kajiado Central County. The study also measures the financial losses livestock keepers incur during drought migration and correlates these losses against livestock keeper’s decision to buy hay for their animals. The study established that the drought in 2017, Kajiado Central County had a 48% hay deficit (2,580,000 hay bales) worth about KES 902 million needed to cover three months of the severest period of the drought. At the same time, hay production and supply were 49,138 grown hay and 3292 purchased hay bales and 6177 bags of commercial feeds and forage. The study also found that 86% of livestock keepers buy hay only when their animals started dying at the severest period of the drought. Hay buying mainly occurs in drought years, and averagely for three months only. From 2005 to 2020, there have been five years of severe drought. Because hay production is a critical climate change adaptation and mitigation strategy for droughts, Kajiado needs to reduce the hay deficit by 67% (average of 2015 & 2017), disaster management planners need to align the hay supply to hay purchasing practices. In addition, decision-makers need to address the low hay supply by tackling the challenges of hay production. Furthermore, disaster management planners could use the study to determine the trigger points to start disaster response for livestock feed.

Causes and Changes of Drought in China:Research Progress and Prospects

Drought is one of the most serious and extensive natural hazards in the world.Subject to monsoon climate variability,China is particularly influenced by drought hazards,especially meteorological drought.Based on a comprehensive understanding of the current status of international drought research,this paper systematically reviews the history and achievements of drought research in China since the founding of the People’s Republic of China,from four main perspectives:characteristics and spatiotemporal distribution of historical and recent drought events,drought formation mechanism and change trend,drought hazard risk,and the particular flash drought.The progress and problems of drought research in China are analyzed and future prospects are proposed,with emphasis on the multi-factor synergetic effect for drought formation;the effect of land-atmosphere interaction;identification,monitoring,and prediction of flash drought;categorization of drought and characteristics among various types of drought;the agricultural drought development;drought response to climate warming;and assessment of drought hazard risks.It is suggested that strengthening scientific experimental research on drought in China is imperative.The present review is conducive to strategic planning of drought research and application,and may facilitate further development of drought research in China.

Mapping the Global-Scale Maize Drought Risk Under Climate Change Based on the GEPIC-Vulnerability-Risk Model

Drought is projected to become more frequent and increasingly severe under climate change in many agriculturally important areas.However,few studies have assessed and mapped the future global crop drought risk—defined as the occurrence probability and likelihood of yield losses from drought—at high resolution.With support of the GEPIC-Vulnerability-Risk model,we propose an analytical framework to quantify and map the future global-scale maize drought risk at a 0.5°resolution.In this framework,the model can be calibrated and validated using datasets from in situ observations(for example,yield statistics,losses caused by drought)and the literature.Water stress and drought risk under climate change can then be simulated.To evaluate the applicability of the framework,a global-scale assessment of maize drought risk under 1.5℃warming was conducted.At 1.5℃warming,the maize drought risk is projected to be regionally variable(high in the midlatitudes and low in the tropics and subtropics),with only a minor negative(-0.93%)impact on global maize yield.The results are consistent with previous studies of drought impacts on maize yield of major agricultural countries around the world.Therefore,the framework can act as a practical tool for global-scale,future-oriented crop drought risk assessment,and the results provide theoretical support for adaptive planning strategies for drought.

Assessment of drought risk for winter wheat on the Huanghuaihai Plain under climate change using an EPIC model-based approach

Climate change-induced drought poses a serious negative impact on global crop production and food security.The Huang Huai Hai(HHH)Plain,one of the most important grain production areas in China,is heavenly stricken by drought.Motivated by formulating drought risk prevention strategies that adapt to climate change on the HHH Plain,therefore,the present study aims to quantitatively evaluate the winter wheat drought risk under multiple climate scenarios using the Environmental Policy Impact Climate(EPIC)model.Based on the well-validated EPIC model,the drought hazard intensity(dHI),physical vulnerability(pV),and drought risk(dR)of the HHH Plain from 2010 to 2099 are assessed.Temporally,the dR showed an increasing trend in the long term,the high dR areas increased by 0.63%and 1.18%under the RCP4.5 and RCP8.5 scenarios,respectively.Spatially,dR showed a pattern of high in the south and low in the north whether under RCP4.5 or RCP8.5 scenario.Comparatively,the dR was 0.211 under the RCP4.5 scenario which was slightly higher than that under the RCP8.5 scenario,i.e.0.207.The Huanghuai Plain agricultural subregion will be a high dHI-pV-dR region.The temperature increase might be the main factor affecting the wheat drought risk.

Attentiveness to Early Warning Drought Information:Implications for Policy Support and Climate Risk Reduction in Ghana

Successful drought planning is dependent on the generation of timely and accurate early warning information.Yet there is little evidence to explain the extent to which crop farmers pay attention to and assimilate early warning drought information that aids in the policy formulation in support of drought risk reduction.A socioecological survey,using a structured questionnaire administered to 426 crop farming households,was carried out in the Talensi District of the Upper East Region,Ghana.The data analytic techniques used were frequency tables,relative importance index,and multinomial logistics embedded in SPSS v.20 software.The results show that crop farmers predominantly rely on agricultural extension officers for early warning drought information,with an estimated 78% of them paying little to very much attention to the information.The likelihood ratio Chi-square test showed that there is a significant improvement in fit as X^(2)(20)=96.792,p<0.000.Household status,average monthly income,and age were the significant predictors for crop farmers paying no attention at all to early warning drought information,while household status was the only significant factor among those paying a little attention.The drive to build a climate-resilient society with effective early warning centers across Ghana will receive 60% lower support from crop farmers paying no to a little attention as compared to farmers paying very much attention to early warning drought information.Broader stakeholder engagements should be carried out to harness inclusive support from crop farmers to build a climate-resilient society in Ghana.

蒙古高原植被净初级生产力干旱风险

The increasing frequency of recent droughts has an adverse effect on the ecosystem of the Mongolian Plateau.The growth condition of NPP is considered an indicator of the ecological function.Therefore,identifying the relationship between NPP and drought can assist in the prevention of drought-associated disasters and the conservation of the ecological environment of the Mongolian Plateau.This study used the Carnegie-Ames-Stanford Approach(CASA)model to simulate the NPP capacity of the Mongolian Plateau between 1982 and 2015,as well as drought indicators(drought probability,vulnerability,and risk)to explore the drought risk of NPP.The findings pointed to an overall increase in NPP with regional variances;however,the NPP rate in Inner Mongolia was considerably higher than that in Mongolia.The standardized precipitation evapotranspiration index(SPEI)showed an overall downward trend,with Inner Mongolia experiencing a substantially lower rate of decline than Mongolia.The areas most likely to experience drought were primarily in the center and north while the areas with the highest drought vulnerability were primarily in the northeast,center,and southeast.Mongolia showed a higher probability of drought compared to Inner Mongolia.Drought-prone regions of the Mongolian Plateau increased during the 21st century while drought-vulnerable areas increased and shifted from north to south.Alpine grasslands and coniferous forests were least vulnerable to drought,while other vegetation types experienced temporal variation.In the 21st century,the primary determinants of drought risk shifted from precipitation and the normalized difference vegetation index(NDVI)to temperature and relative humidity.