Urban Economic Cluster Template and Its Dynamics of Beijing,China     

YANG Zhenshan  LIANG Jinshe  CAI Jianming 《中国地理科学(英文版)》2014,(6):740-750

Economic clusters have been a central focus of current urban and regional research, policies and practices. However, a meth- odology to identify and analyze policy-relevant economic cluster dynamics is still not well developed. Based on input-output （I-O） data of 1987, 1992, 1997, 2002 and 2007 of Beijing, this article presents an adapted principle component analysis for identifying the evolu- tion of local economic cluster patterns. This research addresses the changes of economic interaction of industries with complementary and common activities over time. The identified clusters provide an insight into the reality of economic development in a diversifying urban economy： the increasing importance of services and the growing interaction between service and manufacturing industries. Our method therefore provides the analysts with a better understanding of the emergence, disappearance and development of economic clus- ters citywide. The results could be used to assist monitoring urban economic development and designing more practical urban economic strategies.  相似文献   

Evolution and spatial patterns of spheres of urban influence in China   总被引：2，自引：1，他引：1  

Kaiyong Wang  Yu Deng  Daowei Sun  Tao Song 《中国地理科学(英文版)》2014,24(1):126-136

This article presents the findings of a study of the spheres of urban influence with regard to all cities in China（not including Hong Kong,Macau and Taiwan Province of China）in the years 1990,2000 and 2009.An optimized gravity model with comprehensive time distance was used to carry out a detailed analysis of the spatial patterns of Chinese spheres of urban influence and the spatial characteristics of urban agglomerations.Such urban agglomerations are characterized by high density population and a developed economy,which are also considered as the national competition unit.This paper initially identifies four spatial patterns of urban agglomerations based on the spatial layout of city groups during their evolution.Some basic characteristics of urban agglomerations are outlined,including the number of cities,the size of cities and the functions of urban centers.These characteristics are examined by using statistical methods and Geographic Information System（GIS）.The main findings from this research are that the development stages and structures of urban agglomerations in China vary significantly.It is also clear that the stages and evolution of spatial patterns are strongly affected and dominated by both policy and location factors.  相似文献   

基于拓扑与形态特征的城市道路交通状态空间自相关分析     

刘康  段滢滢  陆锋 《地球信息科学学报》2014,(3):390-395

城市道路交通状态具有空间自相关特征。某一道路交通状态的变化会对其周边道路产生影响,故把握道路交通状态的空间自相关性是提高交通规划、交通预测水平的基础。然而,城市道路交通状态又具有空间异质性,即道路交通状态的影响扩散并非各向同性,其使得道路交通状态空间自相关性的度量更为复杂,因此仅从地理空间下道路之间的邻近关系出发进行分析有失偏颇。同时,城市道路具有拓扑结构特征和几何形态特征,二者对于交通状态自相关性的影响和制约,却未引起足够重视。本文从城市道路的拓扑结构特征和几何形态特征出发,提出了一种新的交通状态空间自相关路段识别规则,即基于交通状态变化的路段空间识别规则,通过拓扑社区发现方法刻画路段在空间上的聚集特征,同时,基于Stroke跟踪的几何形态概化来描述道路交通状态变化影响的空间异质性。结果表明,利用本文提出的识别规则产生的交通状态自相关路段集合,较仅考虑地理空间邻近或拓扑结构的识别规则更为合理,更好地揭示了城市道路交通状态的空间自相关特征。  相似文献   

整合多源异构的城市规划数据进行认知交流的研究     

董志  黄初冬 《地理信息世界》2014,(5)

针对整个城市规划过程的参与者对规划数据的不同种类、不同层次认知需求,本文利用本体思想对包括GIS数据、规划文档、规划图件等多源异构的规划数据进行关系重构,设计本体模型要素的数据语义关系,定义数据间的关联关系,实现基于本体方法的规划领域语义表达算法,方便了各类规划参与者对规划方案认识的交流:同时根据用户特征分类,进行本体关系的逻辑推理,过滤冗余信息,进行多源异构规划数据的可视化。  相似文献   

上思县油茶栽培气候生态条件分析     

黄敏堂  黄清堂  王国安  吴晓伟 《气象研究与应用》2014,35(3):79-81

通过对上思县及全国其它适宜种植区的油茶栽培中油茶开花授粉、果实膨大、油脂积累等重要生长发育期的气象条件分析,找出上思县适宜发展油茶种植的科学依据,为当地发展油茶业提出建议,为当地林业可持续发展提供参考。  相似文献   

广西气候对注射模型的影响及维护措施     

陈细瑜  张丽君  刘霞 《气象研究与应用》2014,(2):66-68

探讨广西不同气候条件下保养教学用注射模型的有效措施.方法：选取320具注射模型作为研究对象,将注射模型按随机编号抽签法分为4份,每份80具模型.分别于2013年春夏秋冬四个季节进行研究,每个季节的80具模型随机分成实验组和对照组各40具.对照组按照模型生产厂家的产品使用、保养要求进行保养,实验组针对广西四季的气候条件采用不同的维护方法进行维护.结果：针对广西气候条件采用不同的维护方法,模型发霉率明显低于传统的保养方法（P＜0.05）.结论：根据广西不同的气候条件对教学用注射模型采用不同的维护方法,对防止模型霉变、延长使用寿命具有重要意义.  相似文献   

The Soil Moisture and Net Primary Production Affected by CO_2 and Climate Change Using a Coupled Model          下载免费PDF全文

PENG Jing  DAN Li 《大气和海洋科学快报》2014,(4):269-274

In this paper, a coupled model was used to estimate the responses of soil moisture and net primary production of vegetation （NPP） to increasing atmospheric CO2 concentration and climate change. The analysis uses three experiments simulated by the second-generation Earth System Model （CanESM2） of the Canadian Centre for Climate Modelling and Analysis （CCCma）, which are part of the phase 5 of the Coupled Model Intercomparison Project （CMIP5）. The authors focus on the magnitude and evolution of responses in soil moisture and NPP using simulations modeled by CanESM, in which the individual effects of increasing CO2 concentration and climate change and their combined effect are separately accounted for. When considering only the single effect of climate change, the soil moisture and NPP have a linear trend of 0.03 kg m^-2 yr^-1 and-0.14 gC m^- 2 yr^-2, respec- tively. However, such a reduction in the global NPP results from the decrease of NPP at lower latitudes and in the Southern Hemisphere, although increased NPP has been shown in high northern latitudes. The largest negative trend is located in the Amazon basin at -1.79 gC m^-2 yr^-2. For the individual effect of increasing CO2 concentration, both soil moisture and NPP show increases, with an elevated linear trend of 0.02 kg m^-2 yr^-1 and 0.84 gC m^-2 yr^-2, respectively. Most regions show an increasing NPP, except Alaska. For the combined effect of increasing atmospheric CO2 and climate change, the increased soil moisture and NPP exhibit a linear trend of 0.04 kg m^2 yr^-1 and 0.83 gC m^2 yr^-2 at a global scale. In the Amazon basin, the higher reduction in soil moisture is illustrated by the model, with a linear trend of-0.39 kg m^-2 yr^-1, for the combined effect. Such a change in soil moisture is caused by a weakened Walker circulation simulated by this coupled model, compared with the single effect of increasing CO2 concentration （experiment M2）, and a consequence of the reduction in NPP is also shown in this area, with a linear trend of-  相似文献   

黑龙江省未来41年气候变化趋势与突变分析   总被引：1，自引：0，他引：1  

张婧婷  冯利平  潘志华 《气象与环境科学》2014,37(3):60-66

选用由英国Hadley中心区域气候模式系统PRECIS构建的基准时段（1961—1990年）和未来时段（2010--2050年）A2、B2情景气候数据,应用线性倾向估算法、累积距平及Mann—Kendall法对排放情景特别报告（SRES）中A2和B2情景下黑龙江省2010--2050年的平均气温、平均最高最低气温、降水量的变化趋势和突变进行了分析。结果表明：相对于基准气候（1961--1990年）,未来41a平均气温表现出明显的上升趋势,A2、B2情景下年均气温分别升高1．63℃和1．94℃,突变分别发生在2031年和2033年;相对于基准气候,A2、B2情景下未来41a降水量分别增加5．3％和1．1％,降水量变化趋势不同,A2情景下为4．03mm／10a,B2情景下为5．94mm／10a,但趋势均不显著,且没有突变发生。总体上,黑龙江省未来41a的气候为向暖湿变化的趋势。  相似文献   

EMD方法在广西夏季降水量预测中的应用     

马军  陆甲  赵金彪 《气象研究与应用》2014,35(3):31-35

对广西夏季降水量进行EMD分解后,利用均生函数相关法,比较不同IMF分量组合建模的预测,不同组合试验预测显示,用前二个IMF分量组合建模预测是最佳的组合方案。经对2001—2010年共10年广西夏季降水量实际预测检验表明,趋势预测准确率达70%以上,对夏季降水量预测较有参考价值。为基层台站的气候预测及服务提供一个客观预测方法。  相似文献   

Preliminary Assessment of the Common Land Model Coupled with the IAP Dynamic Global Vegetation Model          下载免费PDF全文

ZHU Jia-Wen  ZENG Xiao-Dong  LI Fang  SONG Xiang 《大气和海洋科学快报》2014,7(6):505-509

The Common Land Model（CoLM） was coupled with the IAP Dynamic Global Vegetation Model（IAPDGVM）, and the performance of this combined CoLMIAP model was evaluated. Offline simulations using both the original Common Land Model（CoLM-LPJ） and CoLM-IAP were conducted. The CoLM-IAP coupled model showed a significant improvement over CoLMLPJ, as the deciduous tree distribution decreased over temperate and boreal regions, while the distribution of evergreen trees increased over the tropics. Some biases in CoLM-LPJ were preserved, including the overestimation of evergreen trees in tropical savanna, the underestimation of boreal evergreen trees, and the absence of boreal shrubs. However, most of these biases did not exist in a further coupled simulation of IAP-DGVM with the Community Land Model（CLM）, for which the parameters of IAP-DGVM were optimized. This implies that further improvement is needed to deal with the differences between CoLM and CLM in parameterizations of landbased physical and biochemical processes.  相似文献