环城游憩汀(ReLAM):一种值得探询的新型空间要素

环城游憩带(ReBAM)发展到高级阶段将出现空间聚散形态。城市居民游憩需求的规模扩张和结构变动要求ReBAM在供给面形成响应。在不少城市,ReBAM已具备一定的整体开发水平,但内部节点(旅游地)发展不均。在此情况下,优化需求-供给的结构性匹配成为ReBAM发展的内在趋势。环城游憩汀(ReLAM)是指依据游憩需求导向,向特定时空内其他游憩节点引送游憩流的现实或潜在功能较强的优势节点。ReLAM以改善ReBAM节点关联为导引,扩展游憩时空行为,促进节点整合互惠,提升居民游憩品质和ReBAM利用水平。ReLAM形成的根本原因是游憩需求增强和时空条件滞后之间的矛盾,分为主观因素驱动、客观因素驱动和混合驱动3种基本类型。游憩需求状态、垂引节点吸引力、时空结构对ReLAM的形成及其功能具有关键影响,游憩市场规模发挥调节作用。ReLAM是兼具集聚和辐射功能的新型空间要素,对非均衡发展的游憩区域具有优先指导价值。     

基于土地集约利用的长株潭城市群建设用地供需仿真模拟

土地集约利用反映了土地利用的综合状态,是协调土地供需平衡的重要指标。运用系统动力学（SD）构建城市建设用地供需反馈关系回路以及指标变量函数,在此基础上,建立长株潭城市群建设用地供需系统模型,仿真模拟低土地集约利用度、中等土地集约利用度、高土地集约利用度三种不同状态条件下,2016-2030年区域的建设用地、工业用地和居住用地供需变化趋势。结果表明：① 研究区用地规模仍处于扩张状态,城市建设用地数量增长速度总体较快。但三种发展状态下用地增长规模、速度存有差异;② 在低集约度模式下,建设用地规模及供地数量大,易造成土地资源的浪费;高集约度模式下,建设用地供给紧缩,用地规模增长缓慢,总规模偏小,不利于城镇化的良性发展;中等集约度模式则在用地规模和供给量上均与社会经济发展相适应,能体现现代城市发展理念;③ 工业用地占建设用地比例保持在15%~21%之间,其中低集约度模式下比例逐年上升,中等和高集约度模式下呈缓慢下降并趋于稳定之势;居住用地占建设用地的比例维持在27%~35%之间,其中低集约度和中等集约度模式用地占比呈下降趋势,高集约度模式比例总体维持在较高水平。研究通过对三种发展模式的设定,确定了不同指标在三种模式下的变化趋势,可为土地供需决策优化、城市建设规划及土地供给侧结构性改革提供科学参考。     

热带湿地公园游憩者行为偏好研究:以广东九龙山红树林国家湿地公园为例

随着人们对湿地公园价值认识的提升,更多游人参与到湿地公园的游憩活动中,以游人的行为活动以及设施需求为出发点建设湿地公园显得尤为重要。以九龙山红树林国家湿地公园为例,采用行为观测法和问卷调查法对游憩者的结构特点、行为特征、游憩偏好和设施要求等多个方面进行了调查与分析。结果表明:男性学生是公园的主要游憩者,多数利用节假日与朋友结伴而来;公园的吸引半径为100 km以内,主要的交通方式是摩托车及私家车;游人最喜欢的游憩活动是欣赏自然风光以及徒步健身;期望增设垂钓、野营、空中观鸟等游憩项目。建议开发有教育价值或有经济收入的游憩项目,根据游客的需求,丰富设施以及完善现有游憩设施,加大管理、保护与宣传力度。     

基于多源数据的夜间经济时空分布格局研究方法

夜间经济是一个城市经济发展和消费水平的重要表征。目前国内外研究者对夜间经济的研究多停留在理论层面,或基于市场调研和问卷调查的小范围精细化研究。本文融合多源数据为夜间经济提供了新的视角,相较于传统的调查数据,具有更加快速、高效、广泛的特点,适合于夜间经济大范围研究。本文基于夜间灯光、POI、OD流等多源数据,采用DBSCAN、K-Means++等空间聚类算法和研究供需关系的盈亏法,分别从消费者角度和商户角度识别厦门市夜间活动热点区域和夜间服务设施分布区域,分析厦门市夜间经济时空分布格局及相关性。研究表明:① 厦门市夜间活动在空间上呈多环状分布并向四周递减,夜间活动热点区域分布受假期的影响因地而异;② 厦门市部分区域已有服务设施未能很好地服务于夜间经济,现有的照明、夜景等夜间灯光基础设施存在供给不足之处;③ 居住人口密度与夜间活动密度呈中度正相关,研究结果具有有效性,夜间服务设施盈亏值及数量、夜间灯光与夜间活动密度呈中、弱度相关,并且餐饮设施更加依赖于夜间灯光。最后,为厦门市未来夜间经济建设提出了根据不同的消费人群和心理提供不同的夜间服务、加强夜间灯光基础设施建设以及市场扶持的举措。研究结论对促进社会就业、增强基础设施使用率有积极意义,同时也能够为城市夜间经济发展和政策制定提供参考。     

福建沿海地区水资源紧缺问题及其解决途径

本文针对福建沿海地区存在的水资源紧问题,通过对福沿海地区水资源数量,供需平衡的分析探讨了水资源紧缺问题存在的主要原因,并结合水资源利用的现状特征,进一步深入评述了现状利用中存在的问题,最后从可持续利用水资源的角度出发,重点讨论解决途径。     

Eutrophication Dynamics of Tolo Harbour, Hong Kong

The time and spatial variation of water quality in Tolo Harbour, a eutrophic landlocked semi-enclosed bay frequented by algal blooms, is studied using a dynamic eutrophication model. Hourly changes of tide levels and currents are computed by a link-node model assuming M₂ tidal forcing. Phytoplankton growth is assumed to be limited by solar radiation, nitrogen and temperature. The model incorporates light acclimation by algae, self-shading, photosynthetic production, nutrient uptake, and a dynamic determination of the carbon to chlorophyll ratio. In particular, sediment-water-pollutant interactions are modelled via an anaerobic benthic layer segment. Using recorded pollution loads and environmental forcing as input, the model predictions of daily-averaged water quality are compared with the extensive water quality monitoring data of the Environmental Protection Department (EPD). The predicted spatial distribution and trends of algal biomass, inorganic nitrogen, dissolved oxygen (DO), as well as sediment oxygen demand (SOD), are in general agreement with field observations.     

香港一富营养河港内的底泥耗氧和营养盐释放

Tolo Harbour has received massive discharges of municipal sewage, agricultural wastes and cottage industrial effluents, via three river systems, in the past two decades before the mid Eighties. The Harbour is almost land locked and poorly flushed. The soft sediment acted as a sink for nutrients and organic pollutants. After a decade of efforts in establishing and enforcing water pollution control legislations and upgrading wastewater treatment facilities, the sediments have turned into sources of nutrients and exert a measurable oxygen demand upon the overlying waters. In vitro measurements showed that the sediments oxygen demand (SOD) was between 17.6 and 54.3 mgo₂ · m^-2 · h^-1. The maximum rates of release of ortho-phosphate phosphorus and ammonia nitrogen were 15.0 and 206.0 mg · m^-2 · h^-1, respectively.     

基于极化相干矩阵的河流水质污染监测初探

利用遥感手段监测水质污染具有监测范围广、实时性强的优点。本研究选择中国南方地区水质变化明显的河流区域作为研究对象,利用C波段星载极化合成孔径雷达(极化SAR)卫星RADARSAT-2提供的数据,对基于极化SAR的河流水质污染监测技术进行了初步研究。首先介绍了电磁波的极化现象以及极化SAR的基本原理;其次结合一次同步测量实验,提取河流区域,并对极化SAR数据与水质常见监测指标的监测数据进行对比分析,通过对10个采样点18组数据的分析发现,极化相干矩阵中的T 22元素与部分水质指标(如五日生化需氧量BOD₅等)具有较强的相关性,从而反映水质的污染状况;并通过实测数据和最小二乘法,拟合得到了利用[T]矩阵元素反演BOD₅的经验公式,拟合系数达到0.82。最后通过对地表散射模型和菲涅尔系数的分析,从理论上探讨了极化相干矩阵中部分元素与水体物理性质存在相关性的原因。初步理论分析和实验数据表明,T 22元素能够反映水体的污染状况。     

Ground motion characteristics of the Chi‐Chi earthquake of 21 September 1999

The purpose of this paper is to investigate the ground motion characteristics of the Chi‐Chi earthquake (21 September 1999) as well as the interpretation of structural damage due to this earthquake. Over 300 strong motion records were collected from the strong motion network of Taiwan for this earthquake. A lot of near‐field ground motion data were collected. They provide valuable information on the study of ground motion characteristics of pulse‐like near‐field ground motions as well as fault displacement. This study includes: attenuation of ground motion both in PGA and spectral amplitude, principal direction, elastic and inelastic response analysis of a SDOF system subjected to near‐field ground motion collected from this event. The distribution of spectral acceleration and spectral velocity along the Chelungpu fault is discussed. Based on the mode decomposition method the intrinsic mode function of ground acceleration of this earthquake is examined. A long‐period wave with large amplitude was observed in most of the near‐source ground acceleration. The seismic demand from the recorded near‐field ground motion is also investigated with an evaluation of seismic design criteria of Taiwan Building Code. Copyright © 2000 John Wiley & Sons, Ltd.     

Probabilistic analysis of soil‐structure interaction effects on the seismic performance of structures

This paper revisits the phenomenon of dynamic soil‐structure interaction (SSI) with a probabilistic approach. For this purpose, a twofold objective is pursued. First, the effect of SSI on inelastic response of the structure is studied considering the prevailing uncertainties. Second, the consequence of practicing SSI provisions of the current seismic design codes on the structural performance is investigated in a probabilistic framework. The soil‐structure system is modeled by the sub‐structure method. The uncertainty in the properties of the soil and the structure is described by random variables that are input to this model. Monte Carlo sampling analysis is employed to compute the probability distribution of the ductility demand of the structure, which is selected as the metrics for the structural performance. In each sample, a randomly generated soil‐structure system is subjected to a randomly selected and scaled ground motion. To comprehensively model the uncertainty in the ground motion, a suite of 3269 records is employed. An extensive parametric study is conducted to cover a wide range of soil‐structure systems. The results reveal the probability that SSI increases the ductility demand of structures designed based on the conventional fixed‐based assumption but built on flexible soil in reality. The results also show it is highly probable that practicing SSI provisions of modern seismic codes increase the ductility demand of the structure. Copyright © 2016 John Wiley & Sons, Ltd.