Based on data of agricultural drought situation and sown area of main crops in each county or district of the Sichuan Basin, the spatial distribution and probability of agricultural drought risk at different risk leve...Based on data of agricultural drought situation and sown area of main crops in each county or district of the Sichuan Basin, the spatial distribution and probability of agricultural drought risk at different risk levels were studied using normal information diffusion method, and the risk zoning was carried out. The results showed that normal information diffusion method could fit the distribution of agricultural drought risk in the Sichuan Basin. By comparison with the end of the 20^th century, agricultural drought risk in Meishan, Chongqing City and so on increased at the beginning of the 21^st century when x1≥ 10% or x1≥40%. Agricultural drought risk was low in the west of the Sichuan Basin, which was related to rich precipitation here, but it was high in Bazhong, Zhongjiang, Luxian and so forth. The risk zoning results can provide scientific references for disaster prevention and emergency management of government.展开更多
The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, d...The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer （D-S） evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. （2005）, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.展开更多
Risk assessment of distributed energy system often has uncertainty and subjective problems. The problems will have some impact on the results. To solve the problems, a method of improved fuzzy analytic hierarchy proce...Risk assessment of distributed energy system often has uncertainty and subjective problems. The problems will have some impact on the results. To solve the problems, a method of improved fuzzy analytic hierarchy process is proposed. By using the fuzzy analytic hierarchy process method, a hierarchical analysis model is established. And then according to the given judgment matrix of each index layer, we calculate whether it meets the consistency condition. And then if the judgment matrix does not meet the consistency condition, the problem will be solved by the improving of particle swarm optimization (PSO) with Kalman filter. The practice in the distributed energy system shows that the method can not only fully reflect the fuzziness of assessment elements and process, but also reduce the influence of individual subjective factors and better evaluation results can be achieved.展开更多
为了减轻旱灾对辽宁地区玉米生产的影响,该文通过对辽宁省23个气象站点46 a气象数据和气象站点所在县玉米产量、种植面积的分析,用实际干旱发生频率、农业气象干旱发生频率、玉米生产相对暴露率和单产水平等4个因素构建了辽宁地区玉米...为了减轻旱灾对辽宁地区玉米生产的影响,该文通过对辽宁省23个气象站点46 a气象数据和气象站点所在县玉米产量、种植面积的分析,用实际干旱发生频率、农业气象干旱发生频率、玉米生产相对暴露率和单产水平等4个因素构建了辽宁地区玉米干旱风险指数,用社会科学统计程序(statistical program for social sciences)和地理信息系统(geographic information system)对辽宁地区玉米干旱进行了风险分析和风险区划。结果表明,辽宁省有30%的站点处于玉米干旱较高或高风险区,主要分布于辽西山地丘陵和辽南沿海地区;玉米干旱中等风险区主要分布在辽西走廊和辽中平原及渤海湾附近地区;玉米干旱低风险区主要分布在辽东山地丘陵地带。经检验50%以上站点的干旱风险指数与玉米相对气象产量显著相关。所构建的辽宁地区玉米干旱风险指数能客观地反应干旱对玉米生产的影响。该研究为玉米避灾和减灾管理提供科学依据。展开更多
文摘Based on data of agricultural drought situation and sown area of main crops in each county or district of the Sichuan Basin, the spatial distribution and probability of agricultural drought risk at different risk levels were studied using normal information diffusion method, and the risk zoning was carried out. The results showed that normal information diffusion method could fit the distribution of agricultural drought risk in the Sichuan Basin. By comparison with the end of the 20^th century, agricultural drought risk in Meishan, Chongqing City and so on increased at the beginning of the 21^st century when x1≥ 10% or x1≥40%. Agricultural drought risk was low in the west of the Sichuan Basin, which was related to rich precipitation here, but it was high in Bazhong, Zhongjiang, Luxian and so forth. The risk zoning results can provide scientific references for disaster prevention and emergency management of government.
基金supported by the National Natural Science Foundation of China(Grants No.51190094,50909073,and 51179130)the Hubei Province Natural Science Foundation(Grant No.2010CDB08401)
文摘The weights of the drought risk index （DRI）, which linearly combines the reliability, resiliency, and vulnerability, are difficult to obtain due to complexities in water security during drought periods. Therefore, drought entropy was used to determine the weights of the three critical indices. Conventional simulation results regarding the risk load of water security during drought periods were often regarded as precise. However, neither the simulation process nor the DRI gives any consideration to uncertainties in drought events. Therefore, the Dempster-Shafer （D-S） evidence theory and the evidential reasoning algorithm were introduced, and the DRI values were calculated with consideration of uncertainties of the three indices. The drought entropy and evidential reasoning algorithm were used in a case study of the Haihe River Basin to assess water security risks during drought periods. The results of the new DRI values in two scenarios were compared and analyzed. It is shown that the values of the DRI in the D-S evidence algorithm increase slightly from the original results of Zhang et al. （2005）, and the results of risk assessment of water security during drought periods are reasonable according to the situation in the study area. This study can serve as a reference for further practical application and planning in the Haihe River Basin, and other relevant or similar studies.
文摘Risk assessment of distributed energy system often has uncertainty and subjective problems. The problems will have some impact on the results. To solve the problems, a method of improved fuzzy analytic hierarchy process is proposed. By using the fuzzy analytic hierarchy process method, a hierarchical analysis model is established. And then according to the given judgment matrix of each index layer, we calculate whether it meets the consistency condition. And then if the judgment matrix does not meet the consistency condition, the problem will be solved by the improving of particle swarm optimization (PSO) with Kalman filter. The practice in the distributed energy system shows that the method can not only fully reflect the fuzziness of assessment elements and process, but also reduce the influence of individual subjective factors and better evaluation results can be achieved.
文摘为了减轻旱灾对辽宁地区玉米生产的影响,该文通过对辽宁省23个气象站点46 a气象数据和气象站点所在县玉米产量、种植面积的分析,用实际干旱发生频率、农业气象干旱发生频率、玉米生产相对暴露率和单产水平等4个因素构建了辽宁地区玉米干旱风险指数,用社会科学统计程序(statistical program for social sciences)和地理信息系统(geographic information system)对辽宁地区玉米干旱进行了风险分析和风险区划。结果表明,辽宁省有30%的站点处于玉米干旱较高或高风险区,主要分布于辽西山地丘陵和辽南沿海地区;玉米干旱中等风险区主要分布在辽西走廊和辽中平原及渤海湾附近地区;玉米干旱低风险区主要分布在辽东山地丘陵地带。经检验50%以上站点的干旱风险指数与玉米相对气象产量显著相关。所构建的辽宁地区玉米干旱风险指数能客观地反应干旱对玉米生产的影响。该研究为玉米避灾和减灾管理提供科学依据。
