基于RS的西安市地表温度反演及城市热环境研究

发布时间：2018-01-20 06:53

本文关键词： 西安市地表温度热环境景观格局遥感　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：伴随着城市化、工业化的快速发展,地表土地利用/覆盖类型和景观格局发生了改变,城市热环境发生了变化,一系列环境和生态问题接踵而至。自1988年城市热岛效应首次被提出以来,城市热环境问题逐渐受到重视。现如今,城市热环境问题不仅是学术界研究的焦点和热点,也是构建新型现代化都市需要合理处理的问题。西安市位于黄河流域中部的关中平原,近年来在西部大开发和建设国际化大都市战略的推进下,城市范围不断扩张,热环境问题日益突出。基于遥感,本文利用1992年7月17日、2006年7月24日和2013年6月25日的Landsat-5 TM和Landsat-8 TIRS-OLI数据,通过单窗算法反演西安市城六区的地表温度,并对不同时期的西安市地表温度状况进行分析和评价;引入景观生态理论,利用景观格局指数对西安市城六区的热力景观格局动态演变进行分析和评价;提取研究区归一化植被指数(NDVI)、归一化建筑指数(NDBI)和水体指数(NDWI),利用特征剖面提取的方法对研究区城市热岛效应与植被、建筑覆盖及水体的关系进行研究,并结合监督分类的结果探讨裸地、城市建筑区、绿地、水体与地表温度的量化关系。结论如下:(1)从1992年到2013年,西安市热岛效应呈现增强趋势。根据温度归一化法等级划分结果表明:1992年至2013年,超热岛区面积百分比从0.03%增加到9.76%,热岛区从0.56%增长至54.76%,中间区从11.93%扩大到30.09%,而绿岛区的面积百分比从84.19%减少至4.45%,超绿岛区面积百分比从3.28%减少至0.95%。其中,热岛区面积大幅度增加,范围不断由城市中心向外围延伸发展;绿岛区面积递减,范围不断缩小。热岛效应呈现出增强的趋势。(2)热力景观空间分布发生变化。西安市热岛区21年来呈现散点状-连片状-扩散转移状的变化特征,1992年热岛区散点状分布于主城区,2006年连片状覆盖主城区,而2013年城市热岛区由“市区”扩散转移到“郊区”。(3)热力景观格局时空差异较大,但逐渐趋于稳定。从斑块面积来讲,1992年景观格局面积中占主导类型的是绿岛区,到2006年是中间区,2013年热岛区成为斑块面积中最大的;从聚集度来讲,从1992年到2013年,景观要素不断地趋于聚集;从景观水平上来说,景观要素破碎度不断降低,斑块分布不断趋于稳定。(4)地表温度与地表覆盖类型存在相关关系。地表温度(LST)与归一化植被指数(NDVI)存在显著的负相关关系;LST与归一化建筑指数(NDBI)呈现正相关关系;LST与水体指数(NDWI)存在负相关关系,表明绿地和水体具有很好的降温作用。经过监督分类得到的地表覆盖类型与地表温度叠加得到:1992年和2006年地表覆盖各类型的平均温度由高到低排列次序为:城市建筑区裸地绿地水体,到2013年次序发展为:裸地城市建筑区绿地水体。因此,合理控制城市建筑区面积和裸地面积,有效增加绿地面积和水域面积,对于缓解城市热岛效应具有积极作用。
[Abstract]:With the rapid development of urbanization and industrialization, the land use / cover type and landscape pattern have changed, and the urban thermal environment has changed. A series of environmental and ecological problems followed. Since 1988, the urban heat island effect was first proposed, the urban thermal environment problem has been gradually paid attention to. Now. The problem of urban thermal environment is not only the focus and hot spot of academic research, but also the problem of constructing a new modern city, which is located in Guanzhong Plain in the middle of the Yellow River Basin. In recent years, with the development of western China and the strategy of building an international metropolis, the urban scope is expanding and the thermal environment problem is becoming more and more serious. Based on remote sensing, this paper uses July 17th 1992. Landsat-5 TM and Landsat-8 TIRS-OLI data from July 24th 2006 and June 25th 2013. The single window algorithm is used to retrieve the surface temperature of the six districts of Xi'an city, and to analyze and evaluate the state of the surface temperature of Xi'an city in different periods. Based on landscape ecology theory and landscape pattern index, the dynamic evolution of thermal landscape pattern in six districts of Xi'an city was analyzed and evaluated. The normalized vegetation index (NDVI), normalized building index (NDBI) and water body index (NDWI) were extracted from the study area. The relationship between building cover and water body was studied, and the results of supervision and classification were used to discuss bare land, urban building area and green space. The quantitative relationship between water body and surface temperature. The conclusion is as follows: from 1992 to 2013. The effect of heat island in Xi'an showed an increasing trend. According to the classification of the temperature normalization method, the area percentage of the super heat island increased from 0.03% to 9.76% from 1992 to 2013. The area of Gedo increased from 0.56% to 54.76, the middle zone expanded from 11.93% to 30.09, and the area percentage of Green Island decreased from 84.19% to 4.45%. The percentage of super green island area decreased from 3.28% to 0.95.The area of heat island area increased greatly, and the area of heat island area continued to extend from the city center to the periphery. The area of Green Island is decreasing. The heat island effect shows an increasing trend. The spatial distribution of thermal landscape changes. In the past 21 years, the heat island area of Xi'an has the characteristics of scattered point-like, even flaky and diffusive transfer. In 1992, the heat island area was scattered in the main urban area, and in 2006, the main urban area was covered with flakes. In 2013, the urban heat island area was transferred from "urban area" to "suburb".) the thermal landscape pattern varied greatly in time and space, but gradually tended to be stable, in terms of patch area. In 1992 the dominant type of landscape pattern area was Green Island area, 2006 was the middle area, 2013 heat island area became the largest patch area; From 1992 to 2013, the landscape elements tend to gather continuously. From the landscape level, the degree of fragmentation of landscape elements is decreasing. The distribution of patches tended to be stable. (4) there was a significant correlation between surface temperature and land cover type, and a significant negative correlation between LST and normalized vegetation index (NDVI). There was a positive correlation between LST and normalized building index (NDBI). There was a negative correlation between LST and water body index (NDWI). The results show that green space and water have a good cooling effect, and the superposition of the surface cover type and the surface temperature obtained by the supervised classification shows that:. In 1992 and 2006, the order of the average temperature of each type of land cover was as follows: urban building area bare green space water body. By 2013, the order is: bare land urban green space water body. Therefore, reasonable control of urban building area area and bare land area, effectively increase the green space area and water area. It plays a positive role in alleviating the urban heat island effect.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X87;X16

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