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991.
In this research, approaches of interval mathematical programming, two-stage stochastic programming and conditional value-at-risk (CVaR) are incorporated within a general modeling framework, leading to an interval-parameter mean-CVaR two-stage stochastic programming (IMTSP). The developed method has several advantages: (i) it can be used to deal with uncertainties presented as interval numbers and probability distributions, (ii) its objective function simultaneously takes expected cost and system risk into consideration, thus, it is useful for helping decision makers analyze the trade-offs between cost and risk, and (iii) it can be used for supporting quantitatively evaluating the right tail of distributions of waste generation rate, which can better quantify the system risk. The IMTSP model is applied to the long-term planning of municipal solid waste management system in the City of Regina, Canada. The results indicate that IMTSP performs better in its capability of generating a series of waste management patterns under different risk-aversion levels, and also providing supports for decision makers in identifying desired waste flow strategies, considering balance between system economy and environmental quality.  相似文献   
992.
BeiDou regional navigation satellite system(BDS)also called BeiDou-2 has been in full operation since December 27,2012.It consists of 14 satellites,including 5 satellites in Geostationary Orbit(GEO),5 satellites in Inclined Geosynchronous Orbit(IGSO),and 4 satellites in Medium Earth Orbit(MEO).In this paper,its basic navigation and positioning performance are evaluated preliminarily by the real data collected in Beijing,including satellite visibility,Position Dilution of Precision(PDOP)value,the precision of code and carrier phase measurements,the accuracy of single point positioning and differential positioning and ambiguity resolution(AR)performance,which are also compared with those of GPS.It is shown that the precision of BDS code and carrier phase measurements are about 33 cm and 2 mm,respectively,which are comparable to those of GPS,and the accuracy of BDS single point positioning has satisfied the design requirement.The real-time kinematic positioning is also feasible by BDS alone in the opening condition,since its fixed rate and reliability of single-epoch dual-frequency AR is comparable to those of GPS.The accuracy of BDS carrier phase differential positioning is better than 1 cm for a very short baseline of 4.2 m and 3 cm for a short baseline of 8.2 km,which is on the same level with that of GPS.For the combined BDS and GPS,the fixed rate and reliability of single-epoch AR and the positioning accuracy are improved significantly.The accuracy of BDS/GPS carrier phase differential positioning is about 35 and 20%better than that of GPS for two short baseline tests in this study.The accuracy of BDS code differential positioning is better than 2.5 m.However it is worse than that of GPS,which may result from large code multipath errors of BDS GEO satellite measurements.  相似文献   
993.
柴达木盆地鄂博梁地区新近系物源分析   总被引:1,自引:0,他引:1       下载免费PDF全文
物源分析是沉积盆地研究的重要内容之一。在对柴达木盆地鄂博梁地区新近系相关资料调研的基础之上,对研究区碎屑岩的碎屑组分、岩屑类型、重矿物组合、砂地比和阴极发光平面分布特征进行分析,并结合地震资料,确定出研究区新近系物源方向:鄂博梁Ⅰ号构造带物源主要来自于北部的阿尔金山,而位于其西部的东坪构造带与鄂博梁Ⅰ号构造带物源区不同,其具有相对独立的物源区;鄂博梁Ⅱ号构造带属于混源区,同时受到2个方向物源的影响,分别是北部的阿尔金山方向和东北部的小赛什腾山方向,前者穿过鄂博梁Ⅰ号构造带到达该地区,是主要的物源区,后者穿过冷湖一、二、三号构造带到达该地区,为次要物源区;鄂博梁Ⅲ号构造带物源主要来自于东北方向的赛什腾山,其是穿过冷湖六、七号构造带到达该地区的,并未受到来自南八仙方向 “古鱼卡大型古河流三角洲”物源的控制。  相似文献   
994.
气象影视设备集约化技术初探   总被引:1,自引:0,他引:1  
目前有些地市局拥有两套非编设备,但是两套设备之间不能联网,达不到随时备份和提高设备利用率的目的。本文通过将两套非编设备并同虚拟机连成局域网,两套非编设备平时各自工作,一套录制,另一套可实时获取录制的素材并进行配音编辑,提高了设备的利用率;同时两套非编设备互为备份,在一套出现故障时,另一套非编能独立承担工作,不需要更改线路。通过气象影视设备的集约化改造,在保障节目质量的前提下,提高了工作效率,两个小时内录制七至八套节目成为现实,同时设备的互为备份,也保障了系统的可靠性。  相似文献   
995.
依据国家草原火险等级划分标准,针对锡林郭勒盟的具体情况对指标体系进行逐月调整,运用多个气象因子和综合因子之间相关来确定草原火险天气等级标准,建立草原火险气象等级预报方程,并开发研制了草原火险气象等级预报服务系统,经过近1年的试运行,能够对草原火险天气进行很好的预报预测,同时指导草原火险的遥感监测业务.  相似文献   
996.
全球年平均人为热释放气候强迫的估算   总被引:6,自引:0,他引:6       下载免费PDF全文
利用能源经济领域具有权威性的英国石油公司(BP)世界能源统计资料和联合国人口统计资料,通过一些简单的数值计算,初步估算了人为热释放的全球气候强迫。结果表明:当前(2008年)全球年平均人为热释放的气候强迫还不是很大,约为0.031W/m2;但随着人口及能源消费总量的增加,未来人为热释放产生的全球年平均气候强迫将有可能达0.30W/m2。  相似文献   
997.
Some variational data assimilation (VDA) problems of time- and space-discrete models with on/off parameterizations can be regarded as non-smooth optimization problems. Same as the sub-gradient type method, intelligent optimization algorithms, which are widely used in engineering optimization, can also be adopted in VDA in virtue of their no requirement of cost functions gradient (or sub-gradient) and their capability of global convergence. Two typical intelligent optimization algorithms, genetic algorithm (GA) and particle swarm optimization (PSO), are introduced to VDA of modified Lorenz equations with on-off parameterizations, then two VDA schemes are proposed, that is, GA based VDA (GA-VDA) and PSO based VDA (PSO-VDA). After revealing the advantage of GA and PSO over conventional adjoint methods in the ability of global searching at the existence of cost functions discontinuity induced by on-off switches, sensitivities of GA-VDA and PSO-VDA to population size, observational noise, model error and observational density are detailedly analyzed. Its shown that, in the context of modified Lorenz equations, with proper population size, GA-VDA and PSO-VDA can effectively estimate the global optimal solution, while PSO-VDA consumes much less computational time than GA-VDA with the same population size, and requires a much lower population size with nearly the same results, both methods are not very sensitive to observation noise and model error, while PSO-VDA shows a better performance with observational noise than GA-VDA. It is encouraging that both methods are not sensitive to observational density, especially PSO-VDA, using which almost the same perfect assimilation results can be obtained with comparatively sparse observations.  相似文献   
998.
In almost all frozen soil models used currently, three variables of temperature, ice content and moisture content are used as prognostic variables and the rate term, accounting for the contribution of the phase change between water and ice, is shown explicitly in both the energy and mass balance equations. The models must be solved by a numerical method with an iterative process, and the rate term of the phase change needs to be pre-estimated at the beginning in each iteration step. Since the rate term of the phase change in the energy equation is closely related to the release or absorption of the great amount of fusion heat, a small error in the rate term estimation will introduce greater error in the energy balance, which will amplify the error in the temperature calculation and in turn, cause problems for the numerical solution convergence. In this work, in order to first reduce the trouble, the methodology of the variable transformation is applied to a simplified frozen soil model used currently, which leads to new frozen soil scheme used in this work. In the new scheme, the enthalpy and the total water equivalent are used as predictive variables in the governing equations to replace temperature, volumetric soil moisture and ice content used in many current models. By doing so, the rate terms of the phase change are not shown explicitly in both the mass and energy equations and its pre-estimation is avoided. Secondly, in order to solve this new scheme more functionally, the development of the numerical scheme to the new scheme is described and a numerical algorithm appropriate to the numerical scheme is developed. In order to evaluate the new scheme of the frozen soil model and its relevant algorithm, a series of model evaluations are conducted by comparing numerical results from the new model scheme with three observational data sets. The comparisons show that the results from the model are in good agreement with these data sets in both the change trend of variables and their magnitude values, and the new scheme, together with the algorithm, is more efficient and saves more computer time.  相似文献   
999.
This paper analyzes the spatial dependence of annual diurnal temperature range (DTR) trends from 1950–2004 on the annual climatology of three variables: precipitation, cloud cover, and leaf area index (LAI), by classifying the global land into various climatic regions based on the climatological annual precipitation. The regional average trends for annual minimum temperature (T min) and DTR exhibit significant spatial correlations with the climatological values of these three variables, while such correlation for annual maximum temperature (T max) is very weak. In general, the magnitude of the downward trend of DTR and the warming trend of T min decreases with increasing precipitation amount, cloud cover, and LAI, i.e., with stronger DTR decreasing trends over drier regions. Such spatial dependence of T min and DTR trends on the climatological precipitation possibly reflects large-scale effects of increased global greenhouse gases and aerosols (and associated changes in cloudiness, soil moisture, and water vapor) during the later half of the twentieth century.  相似文献   
1000.
近45年来河北省极端降水事件的变化研究   总被引:7,自引:1,他引:6  
高霞  王宏  于成文  戴新刚  史丽红 《气象》2009,35(7):10-15
利用河北省1961-2005年逐日降水资料,采用通用的极端气候指数,分析了近45年河北省极端降水事件频率变化的时空特征.结果表明,全省平均年最大日降水量呈下降趋势,1980年为由多向少的转折点;强降水日数和暴雨日数变化不大,但南部平原地区一般减少,北部山地区域多有增加,暴雨日数和强度在1990年代中后期显著增加;降水日数有较明显减少,南部和东南部平原减少更显著;降水日数的减少主要是中、小雨(雪)日数减少造成的.这些结果说明,河北省强降水日数和暴雨日数在降水日数中的比重有增大趋势,强降水量和暴雨降水量在总降水量中的比重可能增加了.这种相对增加趋势主要发生在1990年代中期以后.  相似文献   
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