A PRELIMINARY STUDY ON THUNDERSTORM FORECAST WITH LS-SVM METHOD

The LS-SVM(Least squares support vector machine) method is presented to set up a model to forecast the occurrence of thunderstorms in the Nanjing area by combining NCEP FNL Operational Global Analysis data on 1.0°×1.0° grids and cloud-to-ground lightning data observed with a lightning location system in Jiangsu province during 2007-2008.A dataset with 642 samples,including 195 thunderstorm samples and 447 non-thunderstorm samples,are randomly divided into two groups,one(having 386 samples) for modeling and the rest for independent verification.The predictors are atmospheric instability parameters which can be obtained from the NCEP data and the predictand is the occurrence of thunderstorms observed by the lightning location system.Preliminary applications to the independent samples for a 6-hour forecast of thunderstorm events show that the prediction correction rate of this model is 78.26%,false alarm rate is 21.74%,and forecasting technical score is 0.61,all better than those from either linear regression or artificial neural network.     

南京长江隧道大型泥水盾构施工风险分析及对策

结合南京长江隧道工程复杂的工程及水文地质条件,分析大型泥水盾构过江隧道在施工中存在的重大风险及其可能引起的严重后果。针对不同的风险,组织专家及技术骨干力量进行工程风险评估,梳理了大型泥水盾构过江隧道的风险工程,提出预防措施,并制定风险发生的应急对策,减少和预防重大安全质量事故发生。     

南京市地面塌陷发育特征及影响因素

南京市地面塌陷发生率逐年上升,已成为主要的地质灾害。南京市地面塌陷主要有岩溶塌陷、采空塌陷和工程塌陷3大类型,上世纪主要以岩溶塌陷和采空塌陷为主,近年来,随着城市基础设施建设的扩建,工程塌陷的发生率和破坏性逐渐增加。     

近代南京城市社会空间结构——基于1936年南京城市人口调查数据的分析

以1936年南京城市人口数据为基础,利用城市社会生态因子分析手段,采用聚类分析方法,对南京城市社会空间结构加以分析.结果表明,影响1936年南京城市社会区形成的主因子有城市商业/居住活动因子、政治活动因子、教育因子、贫困人口因子和城市公共福利设施因子等5个.1936年南京城市社会区划分为6个主要类型:①高级政府官员/知...     

城市社区微观空间意象研究——基于南京居民250份手绘草图的比较

选取南京封闭社区与开放社区相互邻近的4个对比组共8个居住社区,对其居民的社会属性、生活习惯和社区空间感知特征进行了问卷调查,并从250份手绘草图中提取和统计相关数据,据此分析城市居民社区空间意象地图的主要类型与构成要素.研究发现,居民的社会属性是影响人们社区空间意象的决定性因素,性别、年龄、收入和居住时间的差异导致居民...     

优质学区社区邻里交往特征及其社会空间效应——以南京市银城小学学区为例

优质学区社区作为当前最为活跃的城市社会空间之一,深刻影响着城市社会空间的重构与分异。基于邻里交往的视角,利用针对南京市银城小学学区居民的问卷调查,分析了优质学区社区的邻里交往特征,据此揭示其社会-空间效应。结果表明:(1)作为典型的名校学区社区,银城小学学区的邻里交往表现出低相识度、浅层次、网络化、低认同度、以教育为中心的特点。(2)透过邻里交往讨论优质学区社区的社会-空间特征:居住和交往空间日益成为物质空壳,交往主体和行为成为没有内容和情感支持的“形式”,流动性加剧又引致社会认同锁定在低水平而难以提升。(3)根本上,优质学区社区的社会-空间凸显分离甚至对立的趋势,不断催生学区社区的异化。     

城市碳足迹与碳循环压力分析——以南京市为例（英文）

Urban carbon footprint reflects the impact and pressure of human activities on urban environment.Based on city level,this paper estimated carbon emissions and carbon footprint of Nanjing city,analyzed urban carbon footprint intensity and carbon cycle pressure and discussed the influencing factors of carbon footprint through LMDI decomposition model.The main conclusions are as follows:(1) The total carbon emissions of Nanjing increased rapidly since 2000,in which the carbon emission from the use of fossil energy was the largest.Meanwhile,carbon sinks of Nanjing presented a declining trend since 2000,which caused the decrease of carbon compensation rate and the increase of urban carbon cycle pressure.(2) The total carbon footprint of Nanjing increased rapidly since 2000,and the carbon deficit was more than ten times of total land areas of Nanjing in 2009,which means Nanjing confronted high carbon cycle pressure.(3) Generally,carbon footprint intensity of Nanjing was on decrease and the carbon footprint productivity was on increase.This indicated that energy utilization rate and carbon efficiency of Nanjing was improved since 2000,and the policy for energy conservation and emission reduction taken by Nanjing's government received better effects.(4) Economic development,population and industrial structure are promoting factors for the increase of carbon footprint of Nanjing,while the industrial carbon footprint intensity was inhibitory factor.(5) Several countermeasures should be taken to decrease urban carbon footprint and alleviate carbon cycle pressure,such as:improvement of the energy efficiency,industrial structure reconstruction,afforestation and environmental protection and land use control.Generally,transition to low-carbon economy is essential for Chinese cities to realize sustainable development in the future.     

南京市灰霾影响因子的数值模拟

利用改进的南京大学空气质量预报系统（NJU-CAQPS）,对2005年1月7日南京典型天气条件形成的污染过程进行了数值模拟,分析了城市人为热源、城市建筑物效应和不同类型人为热源排放对该区域主要污染物分布的贡献及对能见度造成的影响。结果表明,城区日平均能见度最低可达8km以下,一天之中有18h主城区地表能见度低于10km...     

Amenity value in post-industrial Chinese cities: the case of Nanjing

Many Chinese cities are in a transition from industrial to post-industrial urban economies. In this process of urban restructuring, land use becomes polycentric and fragmented. More sophisticated models are needed to estimate the amenity effects of this complex residential environment. This article assesses the relative housing price effects of neighborhood characteristics and accessibility in Nanjing, China. This is achieved with a hedonic price model that incorporates detailed spatial measures, geographical contingency, and a modified version of Alonso’s (1964) general theory of land rent. A crucial finding is that the effect of job accessibility on house price varies depending upon the specific sector of employment. Accessibility to jobs in the public and private service sectors has strong positive effects. However, housing proximity to heavy industries has a spatially nonlinear effect: negative in close proximity, but positive at a larger distance. Second, when we control for job accessibility, access to public transport has an added positive effect. Finally, neighborhood “quality” (defined in terms of nearby amenities) is also relevant, but far less than access to service employment. This research shows that Nanjing’s housing prices are affected by different residential characteristics than those with dominant price effects in Western cities.     

南京都市圈产业效率演化及空间差异分析

都市圈是具有经济一体化趋势的地域空间组织形式,其内部产业效率状态是城市之间存在紧密联系的基础。本文采用数据包络分析（DEA）方法,对南京都市圈内六市四县以及巢湖市市区的产业效率进行分析和空间刻画,结果表明：南京都市圈内产业效率的市域差异,呈现由“中心式结构”向“双核式结构”的过渡趋势,整体产业效率走向相对均衡发展,其中产业效率呈现“东高西低、南高北低”的状态;南京都市圈整体产业效率演化状态趋于增长,其中第二产业的产业效率演化在整个过程中处于主导地位;南京都市圈内的产业效率与其经济实力存在强正相关,经济实力时空格局与南京都市圈产业效率演变的格局基本一致。