| 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.
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