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大峪河年径流量的灰色拓扑预测与趋势分析 总被引:2,自引:0,他引:2
根据灰色拓扑预测方法,利用大峪站1955—1999年径流资料进行参数率定,建立GM(1,1)拓扑预测模型群,并利用2000—2006年径流资料对模型群进行检验。检验结果中,除2006年的相对误差(40.3%)较大外,其余均较小,即模型群可用于径流预测。按此模型预测2007—2016年径流量,采用滑动平均法和Mann-Kendall秩相关检验法对原始径流序列(1955—2006年,序列1)和加入预测值的径流序列(1955—2016年,序列2)进行趋势检验。结果表明:序列1存在下降趋势,但不显著,序列2同样有不明显的下降趋势,但比序列1下降趋势显著,因此大峪河年径流时间序列总体呈下降趋势。 相似文献
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龙刘梯级水库群对黄河生态基流补偿效益 总被引:1,自引:0,他引:1
为完善水库对生态补偿效益计算,文章首先给出水库生态基流补偿效益概念和内涵.同时,提出河流径流生态积分概念和计算公式来度量河流径流生态效益大小;在此基础上,给出量化计算水库生态基流补偿效益计算方法和步骤.最后,以黄河龙羊峡和刘家峡水库2003年调度为例,计算结果显示:2003年龙刘梯级水库对兰州站和花园口站非汛期的生态基流补偿效益分别为177.7亿和289.4亿生态积分;龙刘梯级对兰州和花园口两站的生态补偿效益合计为467.1亿生态积分,龙羊峡对于兰州站和花园口站生态基流补偿效益为318.8亿生态积分,刘家峡对于兰州站和花园口站生态基流补偿效益为148.3亿生态积分.文章旨在通过对黄河生态基流补偿的定量分析,引起有关决策部门对河流生态基流补偿问题的重视,达到抛砖引玉的目的. 相似文献
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Gideon Oron Leonid Gillerman Nissan Buriakovsky Amos Bick Moti Gargir Yonthan Dolan Yossi Manor Ludmilla Katz Josef Hagin 《Desalination》2008,218(1-3):170-180
Treated domestic secondary effluent is a valuable water source that can be reused for diverse purposes. However, in order to minimize health and environmental risks and to maintain adequate levels of sustainable agriculture production on a long range time scale, advanced treatment is required. Advanced effluent quality maintaining minimal risks can be primarily attained by implementing the membrane technology. Field experiments are in progress for secondary wastewater polishing for unrestricted reuse for sustainable agricultural production. The two stage membrane treatment system for the secondary effluent polishing consists of combining two main stages: ultrafiltration (UF) and reverse osmosis (RO) membrane treatment. The UF stage is efficient in the removal of the organic matter and the pathogens while the RO provides the dissolved solids (salinity) removal. Effluent of various qualities is applied for irrigation along with continuous monitoring of the membrane components performance. The experimental data was obtained in the ongoing pilot studies carried out near the City of Arad (Israel) wastewater treatment system (the pilot plant performs in a feed and bleed operation mode). The results indicate the importance of maintaining high quality effluent for sustainable agriculture production. The management modeling gives an idea of the importance in maintaining adequate UF flushing policy in order to minimize expenses due to fouling. 相似文献
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《Energy》2003,28(5):397-409
This paper summarizes the results of a seminal assessment conducted on a fuel cell technology that generates electrical power from landfill waste gas. This assessment at Groton, Connecticut was the second such project conducted by the Environmental Protection Agency (EPA), the first being conducted at the Penrose Power Station near Los Angeles, California. The main objective was to demonstrate the suitability of the landfill gas energy conversion equipment at Groton with different conditions and gas compositions than at Penrose. The operation of the landfill gas cleanup system removed contaminants from the gas stream with essentially the same efficacy as at Penrose, even though the quantity and kinds of contaminants were somewhat different. The fuel cell power plant’s maximum output power improved from 137 kW at Penrose to 165 kW at Groton, due to a 31% increase in the heating value of the Groton landfill gas. 相似文献
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Hilbert-Huang变换能够定量描述非线性、非平稳、弱相依、高度复杂时间序列的时频特性,较传统的时间序列分析方法更具优势。通过对时间序列进行EMD分解,得出其演化过程的内在模函数和趋势项,并对内在模函数做Hilbert-Huang变换,获得序列的变化周期。以汉江上游的两个代表水文站——石泉和安康水文站的年最大洪峰流量为例分析,石泉站年最大洪峰流量变化存在3.06年、7.11年和24.98年的周期,安康站年最大洪峰流量变化存在3.01年、6.07年、15.97年和29.65年的周期,且两站的年最大洪峰流量序列呈降低的趋势。 相似文献
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根据径流量的影响因素往往具有滞后性的特点,在构建神经网络时,从模型复杂度、训练精度、预测精度等方面综合分析了该特性的影响大小,获得了分析滞后性影响的方法。实例表明该方法能够准确判断出滞后时段的大小,为提高径流预报的准确性提供了一条有效的途径。 相似文献
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对干旱区和半湿润区的参考作物蒸散量ET0进行比较。本文采用世界粮农组织(FAO)推荐的Penman-Monteith PM公式(1974)计算得到新疆和田和陕西西安站1956~2005年的逐日ET0序列。将逐日ET0序列统计得到月序列、季序列、年序列,分析了两站的年和四季ET0的长期变化及ET0的年内变化;对年和四季ET0量值进行了影响因素分析。和田和西安的ET0的年内变化和年际变化均呈下降趋势,但是和田的ET0下降趋势不显著,西安的ET0下降趋势显著;气象因素对和田和西安的ET0的影响是相似的,但是日照时数对和田地区的ET0影响比对西安地区的ET0影响弱。 相似文献