共查询到20条相似文献,搜索用时 15 毫秒
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Copula-based risk assessment of drought in Yunnan province,China 总被引:1,自引:0,他引:1
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Natural Hazards - Determining the loss mechanism of drought is crucial for the prevention of and adaptation to agricultural drought. This paper proposes a theoretical framework of agricultural... 相似文献
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Eutrophication,health risk assessment and spatial analysis of water quality in Gucheng Lake,China 总被引:1,自引:1,他引:0
The water characteristics of the Gucheng Lake, such as eutrophication, health and spatial distribution, were investigated.
On the basis of the trophic state index (TSI) and entropy weight, a synthesized trophic state index (STSI) model was established
to assess lake eutrophication condition through calculating STSI, choosing TP, TN, COD, BOD and NH3-N as trophic variables. The STSI ranged from 50.58 to 62.44, which showed that the water has been between eutrophic and supereutrophic.
A histogram was applied to health risk assessment which was analyzed from carcinogenic substances (Cr+6, As and Cd) and non-carcinogenic substances (hydroxybenzene, Pb, Hg, CN− and NH3), and the results showed that the former was much greater than the latter for effect. The total risk for each resident caused
by all pollutants ranged from 5.18E-05 to 8.34E-05, which is far higher than the standard, recommended by Sweden Bureau of
Environment Protection and Holland Ministry of Building and Environment Protection (1.0E-05). Cluster analysis was used to
detect similarities and dissimilarities among the seven sampling sites and explain the observed clustering in terms of affected
conditions. Twenty-one variables were used to divide seven sampling sites into three groups, namely, north lake, south lake
and lake center. 相似文献
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Natural Hazards - Carrying out risk assessments of agricultural drought disasters is helpful to understanding agricultural drought quantitatively and scientifically guiding drought prevention and... 相似文献
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Food security has drawn great attention from both researchers and practitioners in recent years. Global warming and its resultant extreme drought events have become a great challenge to crop production and food price stability. This study aimed to establish a preliminary theoretical methodology and an operational approach for assessing the physical vulnerability of two wheat varieties (“Yongliang #4” and “Wenmai #6”) to agricultural drought using Environmental Policy Integrated Climate model (EPIC). Drought hazard index was set up based on output variables of the EPIC water stress (WS), including the magnitude and duration of WS during the crop-growing period. The physical vulnerability curves of two wheat varieties to drought were calculated by the simulated drought hazard indexes and loss ratios. And the curve’s effect on drought disaster risk was defined as A, B and C sections, respectively. Our analysis results showed that (a) physical vulnerability curves varied between two wheat varieties, which were determined by genetic parameters of crops; (b) compared with spring wheat “Yongliang 4#” winter wheat “Wenmai 6#” was less vulnerable to drought under the same drought hazard intensity scenario; (c) the wheat physical vulnerability curve to drought hazard displayed a S shape, suggesting a drought intensity–dependent magnifying or reducing effect of the physical vulnerability on drought disasters; (d) the reducing effect was mainly in the low-value area of vulnerability curve, whereas the magnifying effect was in the middle-value area, and the farming-pastoral zone and the Qinling Mountain–Huaihe River zone formed important spatial division belts. 相似文献
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Flood loss analysis and quantitative risk assessment in China 总被引:9,自引:4,他引:5
Risk assessment is a prerequisite for flood risk management. Practically, most of the decision making requires that the risks and costs of all risk mitigation options are evaluated in quantified terms. Therefore, a quantitative assessment of possible flood loss is very important, especially for emergency planning and pre-disaster preparedness. This paper presents a preliminary methodology and an operational approach for assessing the risk of flood loss to the population, crops, housing, and the economy at county level in China. The present work assesses the risk of loss for each element (people, crops, and so on) under low-, moderate-, and high-intensity flood using intensity-loss curves and loss rates based on historical flood data from 1990 to 2008. Results show that the counties with high flood risk are primarily located in North, East, Central, and South China, particularly in the lower reaches of rivers. On the other hand, the risk of most counties in the western region is generally lower than that of counties in the eastern region. However, for the entire country, the high-risk regions have both a substantial amount of rainfall and low terrain, making such regions highly prone to flooding. Moreover, these high-risk regions present both high population and wealth density. 相似文献
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Risk may be estimated by multiplying the probability of failure by the consequence. This is acceptable for systems that have a single mode of failure. For systems that have multiple failure modes, such as landslides, the consequences should be assessed individually for each of the failure modes. This paper proposes a new framework of quantitative landslide risk assessment, in which consequences are assessed individually. The framework is generally applicable, and the landslide risk assessments of two typical slopes are presented. 相似文献
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Jun Wang Zhenlou Chen Xiaojing Sun Guitao Shi Shiyuan Xu Dongqi Wang Li Wang 《Environmental Earth Sciences》2009,59(3):645-654
Associated with the rapid urbanization and industrialization, most of the urban parks and recreational areas in Shanghai are
built close to major roads or industrial areas, where they are subject to many potential pollution source, including automobile
exhaust and factory emissions. Urban dusts, containing many toxic heavy metals such as Pb, Cr, Cd, Hg and As, are one of main
contributors for environmental pollution. In this study, 261 dust samples were collected from two different localities (streets
and parks) in the urban area of Shanghai, China. Pb and Cr concentrations of all samples were determined by atomic adsorption
spectrophotometer analyzer, and Cd, As and Hg concentrations in 74 samples by atomic fluorescence spectroscopy. The mean concentrations
of Pb, Cr, Cd, As and Hg are 287, 157, 1.24, 8.73 and 0.16 mg kg−1, respectively. Each heavy metal shows a wide range of concentration values. In comparison with heavy metal background values
of soil in Shanghai, urban dusts have elevated metal concentrations as a whole, except those of As. The concentrations of
Pb, Cr, Cd, As and Hg are 11.3, 2.1, 10.3, 0.997, 1.7 times of the soil background values, respectively. Compared with the
global mean concentrations, Cr concentration in urban dusts is slightly higher. Pb, Cr and Hg show normal distribution after
logarithmic transformation. Pb, Cr, Cd, As and Hg have second-order variation trends of the spatial distribution. The spatial
distribution features of five toxic heavy metals, in general, illustrate relatively high levels within the regions of the
inner-city ring highway and southwestern Shanghai. Cr and Cd are higher in Baoshan industrial park and the shipbuilding industries
regions. The order of environmental risk is Pb > Cd > Cr > Hg > As. Pb and Cd have the highest risk for environment pollution
and human health among the five metals. The pollutant sources of toxic heavy metals in Shanghai urban dusts are preliminarily
concluded as follows: As may have mainly a natural source. Burning of coal has become the main source of Hg pollution. Pb,
Cr and Cd have three sources, traffic, building construction, and weathering corrosion of building materials. 相似文献
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Spatial and temporal analysis of drought risk during the crop-growing season over northeast China 总被引:2,自引:0,他引:2
Xingyang Yu Xingyuan He Haifeng Zheng Ruichao Guo Zhibin Ren Dan Zhang Jixiang Lin 《Natural Hazards》2014,71(1):275-289
Northeast China as an important agricultural zone for commercial and economic crop in China suffered from increased drought risk that seriously threatened agricultural production and food security in recent decades. Based on precipitation datasets from 71 stations from 1960 to 2009 and on the reliable statistical methods of the Mann–Kendall test, Sen’s slope and the Standardized Precipitation Index, we analyzed the temporal and spatial variation of drought occurrence during the crop-growing season (from May to September) and summer (from June to August). The results showed that regional mean precipitation during the crop-growing season and summer over the last 40 years has decreased at the rate of ?1.72 and ?1.12 mm/year, respectively. According to timescale analysis of abrupt changes, there were two distinct time series (1965–1983 and 1996–2009) with decreasing precipitation trends at a 95 % confidence level. A comparison between the two time series of these two periods demonstrated that more frequent and more severe drought occurred during 1996–2009. Furthermore, drought risk in recent decades has become even more serious both in severity and in extent. Especially in the crop-growing season of 2001 and summer of 2007, over 25 % (2.0 × 105 km2) of study area experienced severe drought (serious and extreme droughts). Our results highlight the urgent need for the development of effective drought adaptations for cropland over northeast China. 相似文献
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Upstream inflow decline and excessive water withdrawal are the major reasons for failure in maintaining ecological functions of wetlands and could lead to wetland drought and degradation. Quantitative evaluation of wetlands drought constitutes the basis for managing and scheduling water resources and guaranteeing biological safety. In the study, we proposed a Palmer wetland drought index (PWDI) based on the water balance model that describes wetland hydrological characteristics linked to its located basin to describe drought-reflected ecological characteristics in lacustrine Baiyangdian Wetland and compared it with Palmer drought severity index (PDSI). The results presented that PWDI is able to reflect the worst drought in history, and the drought is mainly affected by water stored in the wetland, but PDSI is inadequate for evaluating the wetland drought. The PWDI methodology provides a clear, objective approach for describing the intensity of drought and can be readily adapted to characterize drought on an operational basis. 相似文献
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Integrated risk assessment of multi-hazards in China 总被引:1,自引:0,他引:1
Maps of population exposure, vulnerability and risk to natural hazards are useful tools for designing and implementing disaster risk mitigation programs in China. The ranking of provinces by relative risk to natural hazards would provide a metric for prioritizing risk management strategies. Using provinces as our study unit, from the perspectives of hazard exposure, susceptibility, coping capacity and adaptive capacity, this study first constructed China’s disaster risk index for five types of major natural hazards: earthquakes, floods, droughts, low temperatures/snow and gale/hail. Then, the relative risk level at the provincial scale in China was assessed. Finally, the hotspots with the highest hazard exposure, vulnerability and risk were identified. The results showed that high exposure was a significant risk driver in China, whereas high vulnerability, especially social vulnerability, amplified the risk levels. Similar to the population exposure to disasters, the relative risk levels in the southwestern, central and northeastern regions of China were significantly higher than those in the eastern, northern and western regions. The high-risk regions or hotspots of multi-hazards were concentrated in southern China (less-developed regions), while the low-risk regions were mainly distributed in the eastern coastal areas (well-developed regions). Furthermore, a nonlinear relationship existed between the disaster risk level and poverty incidence as well as per capita GDP, demonstrating that disaster losses in middle-income areas are likely to increase if economic policies are not modified to account for the rising disaster risk. These findings further indicated that research on disaster risk should focus not only on hazards and exposure but also on the vulnerability to natural disasters. Thus, reducing vulnerability and population exposure to natural hazards would be an effective measure in mitigating the disaster risk at hotspots in China. 相似文献
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Natural Hazards - A strong understanding of severe drought conditions is important for its mitigation and damage alleviation. Given the Peninsular Malaysia’s drought vulnerability and its... 相似文献
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区域气象干旱评估分析模式 总被引:1,自引:0,他引:1
为应对全球范围内日益严重的干旱问题,对区域气象干旱相对完整的评估分析模式开展了探讨。提出了从区域气象干旱识别到干旱特征值计算,再到干旱特征多变量分析的3个分析评估步骤。并以渭河流域为例,对研究区域进行了矩形干旱评估单元划分,选取了RDI(Reconnaissance Drought Index)为评估指标对区域内各单元各时段的干旱状态进行了识别,结果与历史记载的干旱年份吻合较好。分别采用了分布拟合、相关系数和Copula函数等统计学方法对区域干旱的干旱特征值(干旱历时、干旱面积、干旱强度和干旱频率)进行了特征分析,得出了一系列的单变量、双变量及多变量特征分析对比结果。通过对各类分布函数的计算和绘图,得到了渭河流域干旱事件发生的条件概率和重现期,形成了一套相对完整的区域干旱评估分析模式。 相似文献
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Groundwater nitrate contamination and risk assessment in an agricultural area,South Korea 总被引:1,自引:1,他引:1
Jae-Yeol Cheong Se-Yeong Hamm Jeong-Hwan Lee Kwang-Sik Lee Nam-Chil Woo 《Environmental Earth Sciences》2012,66(4):1127-1136
The nitrate of groundwater in the Gimpo agricultural area, South Korea, was characterized by means of nitrate concentration,
nitrogen-isotope analysis, and the risk assessment of nitrogen. The groundwaters belonging to Ca–(Cl + NO3) and Na–(Cl + NO3) types displayed a higher average NO3
− concentration (79.4 mg/L), exceeding the Korean drinking water standard (<44.3 mg/L NO3
−). The relationship between δ18O–NO3
− values and δ15N–NO3
− values revealed that nearly all groundwater samples with δ15N–NO3
− of +7.57 to +13.5‰ were affected by nitrate from manure/sewage as well as microbial nitrification and negligible denitrification.
The risk assessment of nitrate for groundwater in the study area was carried out using the risk-based corrective action model
since it was recognized that there is a necessity of a quantitative assessment of health hazard, as well as a simple estimation
of nitrate concentration. All the groundwaters of higher nitrate concentration than the Korean drinking water standard (<44.3 mg/L NO3
−) belonged to the domain of the hazard index <1, indicating no health hazard by nitrate in groundwater in the study area.
Further, the human exposure to the nitrate-contaminated soil was below the critical limit of non-carcinogenic risk. 相似文献