定西市城市供水可持续发展对策研究          下载免费PDF全文

于春玲 《甘肃地质》2008,(2):71-74

定西市城市供水主要依赖于西部的内官—香泉盆地地下水。本文从定西市城市供水水源地水文地质特征和地下水动态分析入手,指出由于长期的超量开采导致地下水位急剧下降,地下水资源面临枯竭的局面。如何有效的利用地下水资源,以满足定西市城市经济的可持续发展已成为十分紧迫问题。除了采取节水措施,提高水资源的利用率外．跨流域调水是中远期解决定西城市供水的唯一解决途径。  相似文献   

基于Voronoi图的公共服务设施布局优化方法   总被引：5，自引：0，他引：5  

朱华华  闫浩文  李玉龙 《测绘科学》2008,33(2):72-74

公共服务设施的布局优化中一般要考虑两类因子:几何因子与社会经济因子,但现有的方法大多侧重于某一类因子或者其中的部分信息。本文使用Voronoi图为主要的分析手段,给出了基于人口导向、面积导向以及人口-面积综合导向的三种不同的布局优化方法,对现有的设施点进行保留、删除或在此基础上新增服务设施点。通过反复分析,最终实现多类设施空间布局的优化。  相似文献   

Sample Optimization of Ensemble Forecast to Simulate a Tropical Cyclone Using the Observed Track     

Jihang Li  Yudong Gao 《大气与海洋》2018,56(3):162-177

Ensemble forecasting is widely used in numerical weather prediction. However, the ensemble may not satisfy a perfect Gaussian probability distribution because of a limited number of members, with some members significantly deviating from the true atmospheric state. Such outliers (belonging to low probability events) may downgrade the accuracy of an ensemble forecast. In this study, the observed track of a tropical cyclone (TC) is used to restrict the probability distribution of samples by investigating the evolution of TCs. Unlike data assimilation, the method we employed uses observational data. By restricting the probability distribution, ensemble spread could be decreased through sample optimization. In addition, the prediction results showed that track and intensity errors could be reduced by sample optimization. When the vertical structures of TCs considered in this study were compared, different thermal structures were found. This difference may have been caused by sample optimization, which may affect intensity and track. Nevertheless, it should be noted that the replacement of a large number of inferior samples may inhibit the improvement of simulated results.  相似文献   

Idealized Experiments for Optimizing Model Parameters Using a 4D-Variational Method in an Intermediate Coupled Model of ENSO     

Chuan GAO  Rong-Hua ZHANG  Xinrong WU  Jichang SUN 《大气科学进展》2018,35(4):410-422

Large biases exist in real-time ENSO prediction, which can be attributed to uncertainties in initial conditions and model parameters. Previously, a 4 D variational(4 D-Var) data assimilation system was developed for an intermediate coupled model(ICM) and used to improve ENSO modeling through optimized initial conditions. In this paper, this system is further applied to optimize model parameters. In the ICM used, one important process for ENSO is related to the anomalous temperature of subsurface water entrained into the mixed layer(T_e), which is empirically and explicitly related to sea level(SL) variation.The strength of the thermocline effect on SST(referred to simply as "the thermocline effect") is represented by an introduced parameter, αT_e. A numerical procedure is developed to optimize this model parameter through the 4 D-Var assimilation of SST data in a twin experiment context with an idealized setting. Experiments having their initial condition optimized only,and having their initial condition plus this additional model parameter optimized, are compared. It is shown that ENSO evolution can be more effectively recovered by including the additional optimization of this parameter in ENSO modeling.The demonstrated feasibility of optimizing model parameters and initial conditions together through the 4 D-Var method provides a modeling platform for ENSO studies. Further applications of the 4 D-Var data assimilation system implemented in the ICM are also discussed.  相似文献   

区域镇村社区空间网络结构特征及其优化策略     

宿瑞  王成  唐宁  彭清  龙玉琴 《地理科学进展》2018,37(5):688-697

镇村社区空间网络是以镇区为依托、镇村社区为节点、彼此关联为连边构成的空间组织形态,探索其结构特征及其优化策略对引导要素合理流动、提升网络运行效率等具有重要意义。本文选取重庆市沙坪坝区凤凰镇19个镇村社区作为网络节点,采用修正后的引力强度模型反映节点之间的联系,运用GIS工具和社会网络分析法、相关性分析等方法探究镇村社区空间网络结构的总体特征、节点特征及差异特征,提出镇村社区空间网络的优化策略。研究表明：镇村社区空间网络总体处于低水平、非均衡的发展阶段,网络兼具整体松散性与局部集聚性,且小世界特征较为显著,凝聚子群之间的关联性差异明显;镇村社区空间网络呈现“核心-边缘”的节点结构,核心节点的结构洞优势有待加强;社区居民不同的社会属性对网络结构造成了差异性影响;基于此,拟从节点自身功能完善、节点等级体系构建及节点间经济联系强化等方面,构建“1轴、1心、18点”+“1网、57线”的空间网络化模式,为当前及未来的农村社区建设提供示范。  相似文献   

Optimizing the spatial organization of rural settlements based on life quality   总被引：2，自引：0，他引：2  

Chengli Tang  Yanhua He  Guohua Zhou  Shanshan Zeng  Luyao Xiao 《地理学报(英文版)》2018,28(5):685-704

Optimizing rural settlements is an important measure to cope with rural decline, and improve the quality of rural life and attractions. This study introduces the “life quality theory”. Based on the mechanisms governing the interactions between rural settlement space and life quality, this study examines how to optimize the spatial organization of rural settlements. Three aspects are evaluated – the integration of rural settlement spatial functions, optimization of spatial structure, and regulation of spatial scale – with the objective of building an optimization mode and framework for the spatial organization of rural settlements with high life quality. Our results suggest the following: (1) The settlement is the spatial carrier of life quality, which is an essential settlement component, and these two aspects influence and improve each other. Therefore, reasonable rural settlement space is an important precondition for higher life quality. (2) The spatial function types of rural settlements can be divided into those that maintain livelihoods, develop industry, and upgrade life quality. Optimizing spatial organization of rural settlements based on life quality requires promoting the maintenance of livelihood, integration of industrial development, and implantation in quality improvement. (3) There are two important components of optimizing the spatial organization of rural settlements. One is promoting the organic concentration of living, agricultural, and industrial spaces, the reasonable distribution of social intercourse, recreational, and services spaces, and the organic balance of living, production, and ecological spaces, so as to reasonably optimize the combination of internal spatial types in settlements. The other is forming a functional structure level of a “comprehensive village–featured village” and building spatial organization settlement modes connected by rural roads by relocating and adjusting the function of villages. These changes would require the destruction of underdeveloped villages, retaining normal villages, enlarging important villages, and constructing new villages. (4) As an ideal mode for optimizing rural settlements space based on life quality, the Rural Road-Oriented Development Model (RROD model) should be built at a rational scale for unit settlement and distance between settlements, leading to a fully functional RROD system with rational structure, auxiliary facility, and well-organized distribution.  相似文献   

中国自然地域分区研究前沿与挑战   总被引：2，自引：0，他引：2  

彭建  毛祺  杜悦悦  苏冲  张甜  胡熠娜  王仰麟 《地理科学进展》2018,37(1):121-129

分区是地理学认知世界的基本途径。作为综合自然地理学的重要研究内容,自然地域分区通过对区域的划分,有助于进一步认识自然地域系统要素特征及其相互作用过程的地域分异规律,可为制定差异化的空间管治政策提供科学依据。自然地域分区的主题与方法随着社会经济发展在不断变革与创新,本文系统梳理了中国学者在自然地域动态分区、分区界线自动划定与多分区方案定量优选等前沿领域的近期进展,总结了自然地域分区理念、方法的创新与拓展。在此基础上,探讨了新时代自然地域分区在理念、技术与任务方面面临的挑战,建议开展面向人类—自然耦合系统、综合定性与定量途径、从全球到地方多尺度的自然地域分区研究,以期进一步完善自然地域分区理论与方法。  相似文献   

人地系统优化调控的理论方法研究   总被引：2，自引：1，他引：1  

毛汉英 《地理学报》2018,73(4):608-619

在吴传钧先生倡导的人地关系地域系统（简称“人地系统”）理论体系中,人地系统优化调控占据核心位置。本文以吴先生提出的人地系统优化调控的思路及有关论述为主线,在人地系统结构、人地系统非线性效应、人地关系耦合理论、人地系统演进等理论方法方面加以深化与拓展。在此基础上,聚焦于两方面：① 人地系统优化与区域PRED（即人口、资源、环境和发展）协调发展,着重探讨人地系统优化与PRED协调发展的关系,以及PRED协调发展的目标、重点、理论模式和定量测度;② 新时期中国人地系统综合调控的路径与对策,可归纳为：以创新驱动为引领,推动人地系统持续健康发展;以主体功能区划为导向,优化人地系统空间格局;以供给侧结构性改革为主线,建设现代经济体系;以促进人口长期均衡发展为目标,逐步完善人口政策;遵循市场原则,健全资源环境有偿使用和生态补偿机制。  相似文献   

基于多目标改进免疫算法和GIS的养老机构空间配置优化研究——以上海市虹口区为例   总被引：2，自引：2，他引：0  

程敏  崔晓 《地理科学》2018,38(12):2049-2057

综合考虑政府、居民、投资者3方需求,构建带约束多目标的养老机构配置优化模型,基于改进免疫算法和GIS技术,对上海市虹口区养老机构的配置优化问题进行研究,分析研究区现有养老机构在空间分布和规模配置上的合理性,提出优化配置方案。研究表明：研究区现有养老机构数量缺口较大、部分养老机构偏离最佳区位、规模与需求存在较大差距;3所位于江湾镇街道的养老机构在现有区位运行欠合理;为充分满足居民养老需求,需在虹口区南部地区增设15所养老机构;通过与一般免疫算法、遗传算法、粒子群算法、模拟退火算法得到的优化结果对比可知,改进免疫算法在此优化问题中的求解效率分别提高45%,38.89%,21.43%,46.34%,求解精度分别提高1.61%,2.73%,5.80%,6.91%。  相似文献   

基于改进RBF神经网络的GNSS高程拟合     

袁德宝  张建  赵传武  杜世高  彭金英 《大地测量与地球动力学》2020,40(3):221-224

针对传统的RBF神经网络模型在GNSS高程拟合中拟合精度较低、稳定性较差、相关因子需提前人为设置等问题,通过将改进的自适应权重粒子群优化算法与MATLAB RBF神经网络函数newrb相结合,实现RBF神经网络函数模型中隐含节点数和SPREAD值的自动优化选取,提高算法在GNSS高程拟合中的精度和稳定性。通过实例分析,该方法拟合精度高,可达到mm级精度,相对于传统的二次多项式模型精度提高17%,稳定性良好。  相似文献