【作者】 贾刘强；

【导师】 邱建；

【作者基本信息】 西南交通大学 ， 景观工程， 2009， 博士

【摘要】 受城市化和工业化的影响,城市热岛是21世纪人类城市面临的主要环境问题之一,城市绿地是缓解热岛的重要因素。而城市热岛效应不仅受城市绿地中的植被数量的影响,而且受绿地空间布局的影响。对城市绿地缓解热岛的空间特征进行研究,不仅具有探索未知的科学意义,而且在科学规划城市绿地系统、充分发挥城市绿地热环境效应和集约利用土地方面具有重要的实践指导意义。本论文系统性地将遥感、地理信息系统、景观生态学和地理图像信息模型等方法综合应用于城市绿地与热岛的关系研究中,完成的主要工作和取得的主要结论如下：(1)以青岛和成都两市为研究对象,研究了两市的热岛强度和植被盖度空间分布特点,同时给出了分析城市热岛细部特征的方法。结果显示：热岛强度与植被盖度在空间上存在显著负相关性,同时热岛强度除受绿地中植被数量的影响外,还受绿地空间特征,绿地斑块周边环境等因素的综合影响。(2)定量研究了斑块层面绿地缓解热岛的空间规律。a)提出了基于对绿地斑块周边等温线分布规律分析的研究方法,该方法可合理确定绿地斑块对周边环境温度的影响范围和降温程度。b)绿地斑块特征与其内部温度的关系研究结果表明：绿地内部温度与其植被盖度呈显著的负相关性,而与绿地面积、周长和形状指数等空间特征无显著相关性。故降低绿地内部温度的主要途径是增加绿地的植被覆盖程度和绿量。c)绿地斑块对周边温度的影响范围随绿地的面积、周长和形状指数的增大而增大,其中周长对影响范围的影响最大,面积次之。当绿地面积为1.5公顷左右时的影响范围效率最大。d)绿地对周边环境的降温程度随绿地斑块的植被盖度、面积、周长和形状指数的增大而增大,其中绿地面积和周长的影响最大,而绿地面积为1.68公顷左右时的降温程度效率最大。提出了绿地斑块降温地理图像信息模型,该模型对绿地的降温程度有可靠的预测结果。e)在绿地斑块的规划设计中,为使绿地斑块对周边环境温度的影响范围和程度的效率达到最大和最优化,应使绿地斑块的面积接近于1.5-1.68公顷,同时应尽量增大其周长,使绿地边界尽量复杂。提高绿地中植被覆盖率可对降温程度起到积极作用。(3)定量研究了热岛强度与绿地空间特征关系。a)通过引入局部Gi*指数对地表温度的空间集聚度进行了分析,并对分析结果采用计算局部Gi*指数之斜率变点的方法确定了成都2000年热岛范围、次热岛中心和热岛中心的空间分布、大小及规模。该方法可进一步推广应用到其它研究区。b)在对景观聚集度指标AI存在的问题深入分析的基础上,提出了一种改进的聚集度指标AJ,计算结果显示改进后的聚集度指标AJ能更好地反映景观斑块的集中或分散程度。c)在街区(面积约1.3km2)和城区(面积约33.6km2)两种尺度上定量研究了绿地斑块密度指数、平均分维数和聚集度指数与热岛强度的关系,并提出相应的绿地降温地理图像信息模型。结果显示：在两种尺度上,热岛强度与绿地的平均分维数为负相关关系,与绿地斑块密度呈正相关关系；而绿地的聚集度指数与热岛强度在街区尺度上为正相关关系,在城区尺度上则为负相关关系。两种尺度下的绿地降温地理图像信息模型均可很好地预测绿地的降温效果。因此,在规划绿地系统工作中,在努力提高绿地覆盖率和三维绿量的同时,应遵循形状复杂和个数多的原则,而在街区尺度和城区尺度上应分别体现绿地集中和分散原则。(4)初步假设了绿地缓解热岛的空间特征之机理a)研究了绿地对太阳辐射的削减机理,假设了绿地降温热辐射模型(基于绿地削减热辐射功能的降温模型),该模型可从理论层面解释不同植物的降温效果不同的现象。b)在前人研究的基础上,探讨了绿地蒸腾降温机理和影响因素,假设了绿地蒸腾降温模型,该模型可从理论层面解释植物在不同时刻降温能力不同的现象。c)通过理论分析得到绿地面积与其对周边环境温度影响范围之间的关系模型、绿地面积与其对周边环境降温程度之间的关系模型,这些模型可对第4章的相关结论从理论层面给与解释,并初步验证了以上模型的合理性。更多还原

【Abstract】 Urban Heat Island (UHI) is considered as one of the major environmental problem in the 21st century posed to human beings as a result of urbanization and industrialization. The urban green space is the important factor to mitigate the UHI. The UHI effect is influenced not only by urban green space’s vegetation quantity but also by its spatial pattern. Studies on the spatial characteristics of the urban green space’s function of mitigating the UHI, not only have science significance of exploring the unknown, but also have important practice guidance to three aspects such as planning urban green system scientifically, enhancing the green space’s thermal environment effect, and land intensive use. The Remote Sensing (RS), Geographic Information System (GIS), Landscape Ecology and Geographical Image Information Model were used to study the relationship between the urban green space and UHI comprehensively and systematically in thi s thesi s, the mai n research works and obtai ned conclusi ons i n this dissertation are as follows:(1) The Qingdao and Chengdu citiy’s spatial distribution characteristics of Urban Heat Island Intensity (UHII) were researched, and also, the method of analyzing the detail characteristics of UHI was presented. The results showed that there in spatial have a significantly negative correlation between UHII and Vegetation Fraction (VF), and the UHII was affected not only by the vetetation abundance in green space, but also by the spatial characteristics and surrounding condition of green space.(2) The spatial characteristics law of the green patch’s function of mitigating the UHI was studied quantitatively.a) To measure the influence range and degree of green patch’s reducing the surrounding temperature reasonablely, a new method was proposed base on the analysis of the green patch’s surrounding isotherm.b) The study result on the relationship between green patch’s characteristics and its interior temperature shows, the interior temperature is significant negative correlation with the VF but the green patch’s area, perimeter and shape index.Thus, the major approach to reduce the interior temperature is increasing the green patch’s vegetati on abundance.c) The influence range of green patch’s reducing the surrounding temperature increase with the increasing of green patch’s area, perimeter and shape index, the most influential factor is the perimeter, the area take the second place. Especially, the efficiency of influence range reaches the maximum when the green patch’s area is 1.5had) The influence degree of green patch’s reducing the surrounding temperature increase with the increasing of green patch’s VF, area, perimeter and shape index, the area and perimeter have greater influence. Especially, the efficiency of influence degree reaches the maximum when the green patch’s area is 1.68ha The Reducing Temperature Geographical Image Information Model of Green Patch (RTGIIM-GT) was proposed, which could be used to forecast the degree of reduci ng temperature credibly.e) During the process of planning and designing the green patch, to maximize and optimize the efficiency of influence range and degree of green patch’s reducing the surrounding temperature, there have several measure could be useful, such as making the green patch with the area of 1.5-1.68ha, with the perimeter as maximal as possible, and with the shape index as complex as possible. In addition, increase the green patch’s vegetation coverage could play an active role i n reducing the temperature.(3) The relationship between UHII and green space’s spatial distribution characteristics was studied quantitatively.a) The Gi* index was applied to analyzed the aggregation degree of land surface temperature, then, the Gi* curver was plotted and the curver’s slope variable points was caculated. The spatial distribution, area and degree of Chengdu City’s heat island’s center, second heat island’s center and heat island range were determi ned by the slope variable points.b) The problems of landscape aggregation index (AI) were analyzed thoroughly, and an improved aggregation index called AJ. The caculated results show that the AJ produced more reasonable results about the landscape patch’s centralization or decentralization than AI.c) The relationship between the green space’s patch density index (PD), mean fractal dimension (FD), aggregation index (Al) and the UHII were analyzed quantitatively in block district (which area is about 1km2) and city district (which area is about 33km2) scales, the Reducing Temperature Geographical Image Information Model of Green Space (RTGIIM-GS) at both scales was proposed. The research results show that there is a negative correlation between PD and UHII, and active correlation between FD and UHII at the both scales. As to the Al, the correlation with UHII is active at block district scale and negative at city district scale. The green space’s cooling effect can be forecasted by the RTGIIM-GS preferably. So, on the working of planning the urban green system, we should follow the principle of making the green space’s shape complex and number huge, centralization at block district scale and decentralization at city district scale, besides increasing the green space’s vegetation coverage and tri di mensi onal green bi omass as large as possi ble.(4) The mechanisms of spatial characteristics of the urban green space’s UHI mitigating function were discussed.a) The mechanism of the green space’s fucution of attenuating the solar radiation energy was studied. The reducing temperature model based on the green space’s solar radiation attenuating function was developed. The phenomenons of different kinds of plants with different ability of reducing temperature can be expl ai ned by the model.b) Based on the previous research, the mechanism and influence factors of the green space’s transpiration cooling function were discussed. The green space’s transpiration cooling model was proposed, which could be helpful to understand the change of plant’s cooling effect in different time.c) Through the theory analysis, the relational expression of green space’s area and cooling range (or cooling degree) was founded and verified. The relational expression or model could be used to explain the conclusions obtained i n chapter 4 theoreti cally.更多还原