| The rapid development of urbanization has brought far-reaching implications to the environment and the ecological security in the city zone. With the rapid changes of the land use and cover, the physical and chemical features changes of land surface have made a great impact on the transformation between atmospheric water and the energy substance, which have an effect on the urban heat environment. A series of environmental problem and ecological security arised from the urban heat island have made a negative effect on the urban continual development. Therefore. State release《National Plan for Med-to-long-term Scientific and Technological Development》. in which it is requested to study the form mechanism of Urban Heat Island and the man-made technology in order to advance the city function and the city space managing use. Also it emphasizes the essentiality to the Urban Heat environment for constructing the modern urbanization.This study choose the Xi'an metropolitan as the research area, based on the Landsat TM and ETM+from 1988 to 2009, by using the climate data and land use/cover data as an assistant with the quantificational simulation and the GIS technology for evaluation the Land surface temperature in different years and different seasons. This paper also used the theory of Landscape Ecology for assessment of the Heat Island Landscape and the scale effects of Xi'an, Xianyang and Xingping. The paper also discussed the characteristics of spatial-temporal fractal and scale effect on surface temperature of Xi'an. The relationship between changes of land cover and various factors were studied quantitatively; and this paper also discussed the Quantitative influence of land cover of parks to surrounding areas. A UHI-CA-Markov model for urban thermal environment simulation has been developed based on Cellular automata and Markov model. We also analyzed the contribution of the factors to Urban Heat Island effect by using the method of Principal Component Analysis with multiple purposes. The system of control and countermeasures for Urban Heat Island effect were constructed from the adjustment of urban planning, control of industrial heat sources and control of civilian heat sources. In this research, some important results have been concluded:(1) There are different levels of Urban Heat Island effect in Xi'an metropolitan.①The classification system of Urban Heat Island based on the isometric way were suitable for medium and large scale building area to set up the thermal environment of urban indicators and evaluation system, and the Mean Error-based classification system were more suitable for construction four heat environmental indicators and evaluation system of city, county, town, township.②The normal temperature area were dominant at the structure of the thermal environment in Xi'an, Xian yang and Xingping. In the Xi'an and Xianyang, the area size of different UHI types were normal temperature zone>Green island zone>Heat island zone>Strong heat island zone>Strong green zone, and the Xiping city, the area size of different UHI types were normal temperature zone>Heat island zone>Green island zone>Strong heat island zone>Strong green zone.③The land surface temperature in different seasons were changed obviously.(2) The spatial-temporal differentiation of the UHI landscape pattern is very large.①It is indicated by the index of landscape level that:the normal temperature zones was always the dominant patch in Xi'an. Xianyang and Xingping from 1988 to 2006.②The Contagion index showed a higher intensive trend, which suggested that the entire landscape elements of Xi'an. Xianyang and Xingping become a intensive and an disorder trend, with the increasing fragmentation index. Shannon's diversity index and Shannon's evenness index showed a slight reduction at first, followed by slightly decreased trend, which indicated land use in Xi'an were stable over time, with the broken degree decreasing, the pattern of thermal landscape tend to be stabilization.③The surface temperature profile showed similar structural characteristics in different scales. As the research-scale increasing, the profile began to become more smooth and continuous, and the detailed features began to disappear, but the overall trend have been maintained, and when the scale reached 150m, the jump phenomenon were happened, therefore, the 150 m was the maximum scale to study the Urban Heat Island.(3) The expression of quantitative relationships between the land surface temperature and land use and land cover were set up.①The surface temperature of land use and land cover in Xi'an in summer from high to low were as follows:bare land> construction land> woodland> forest land>grass land>water. But in winter were that:forest land> cultivated land>bare land>the construction land>grass land>water.②LST and NDVI showed a significant negative correlation in summer. LST and NDBI presented positive correlation. LST and NDWI showed a typical negative correlation, which showed the water has a good cooling effect in summer.③With the morphological parameters (size, aspect, shape index,etc) of parks to its neighboring region of the thermal environment were different, The park area was a decisive factor to the average temperature. The park average temperature reducer range has a strong positive correlation between the aspect ratio and shape index of park. the extent of reducer average temperature showed a lower level of positive correlation between the water area, length-width and shape index. The Lmax and Tmax of Xing' qing and Datang Park are higher than other parks which have the water less than 30%. Therefore, the park construction, not only should consider its shape, but also should consider the water area. Generally speaking, water area accounts for park area more than 30% is preferred.(4) The results of Xi'an thermal environment simulation indicated that the future heat island effect tend to be better.①The results of the thermal environment simulation of Xi'an in 2012 based on the UHI-CA-Markov model showed that, the strong heat island and heat island area minor reductions, normal temperature area, the green zone present slightly increasing, strong green zone showed a stable trend by contrasting with thermal environment in 2006.②The results of the thermal environment simulation of Xi'an in 2018 respectively compared with the 2012, the strong heat island area showed a few increasing, the heat island area showed a trend of stabilization, the normal temperature was a substantial increasing, green island and strong green island area showed a strong decreasing.③The results of simulation from 2006 to 2018 showed that the future thermal environment of Xi'an tends to be better, normal temperature area is dominated in the research area, but local thermal environment have further deterioration trend. Therefore, the proposal in urban planning and construction of the thermal environment planning for the resident should be considered as an important component.(5) The cause of Urban Heat Island was analyzed and countermeasures systerm was established.①The paper put forward the four aspects to construct the Urban Heat Island system including the factors to increase the UHI were strengthened, to alleviate the factors were reduced, the temporary and permanence factors. And four aspects were further broken down 11 categories and 20 secondary indicators.②The results of PCA analysis showed that the principal component 1 reflected the level and scale of city development, mainly including the urban population, building area information; principal component 2 concentrated reflection of urban heat meteorological factors, including the precipitation, relative humidity and other information; principal component 3 concentrated reflection the weather conditions on the urban thermal environment, including wind speed; principal component 4 concentrated reflection of the urban population, population density and the contribution of the urban thermal environment.③Construction the system of urban heat island effect of Xi'an metropolitan, the system consist of three first-order index and 15 sub-indicators.④Urban planning are presented in the overall planning of urban thermal environment, including the size of city planning, population and the population density planning, urban greening and water master plan. According to industrial heat proposed control the proportion of high fever; effectively reduce the enterprise energy consumption and emissions control "three wastes" absolute. According to civil heat proposed initiative low carbon life concept and build low-carbon ecological and environment protection countermeasures and suggestions.There are some progression and innovation in the article as follows:①The paper introduced the landscape ecology into the thermal environment study, by using the landscape index and the process mechanism of evolution of urban thermal environment. The results showed the approach could very well explanation of spatial-temporal urban thermal environment characteristics of dynamic evolution.②The paper also get the relationship between the different remote sensing index and the surface temperature by the way of the quantitative analysis. We can be better expalining the correlation changes between the different land use and the LST by the fractal theory.③A model named UHI-CA-Markov were set up by combining the cellular automata and markov model, which have achieved a good results for the UHI simulation.④For the thermal environment, A qualitative analysis were presented based on multiple objective analysis of the PCA method, and calculated the various factors on the constribution to the Urban Heat Island, then put forward a evaluation index system of the Urban Heat Island, a Relieving system of Urban Heat Island effect were also established.
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