杭州湾城市群缘色空间时空演变及空间匹配性研究

发布时间：2019-06-21 19:59

【摘要】：随着生活水平的大幅度提高,城市居民对城市环境提出了更高要求。对城市绿色空间的时空变化进行研究,可以加深对快速城市化背景下城市环境演变的理解,为最终实现城市绿色空间的合理布局,促进其生态效益和社会效益的充分发挥提供指导。城市绿色空间分布广泛且高度破碎,受人为活动干扰强烈且演替频繁,实现复杂环境下城市绿色空间的准确提取对遥感数据源的时空分辨率和信息提取方法都提出了更高的要求。本研究以Landsat影像为主要数据源,采用基于亚像元的城市绿色空间信息提取和变化检测方法,研究了杭州湾6个主要城市20多年来市域范围内城市绿色空间的时空动态及景观格局变化,并进一步在街镇尺度上分析了城市绿色空间和公共公园与人口分布的空间匹配性及环境正义问题。主要研究内容和结论如下：(1)采用以多端元光谱混合分析为基础的区域绿色空间信息提取方法,在亚像元水平上提取了杭州湾城市群主要城市1990、2002和2013年城市绿色空间信息。首先采用阈值法对影像进行纯植被掩膜,有效地减小了模型运算量以及纯植被覆盖区域植被光谱细微变化所带来的干扰。通过在传统VIS模型中加入水体和阴影端元,可以在水绿共生为特色的典型江南水乡城市中较好的提取出湿地、农田水网以及城市内部水体周边的绿色空间信息。此外,在确定不同复杂水平模型的端元光谱时,通过对二端元模型运行结果的检视来选择合适的端元光谱来运行三端元和四端元模型,可以在保证精度的同时提高运算效率。结果表明,以多端元光谱混合分析为基础的区域绿色空间信息提取方法可以较准确地提取城市绿色空间信息,尤其是城市内部零散分布的小斑块绿色空间和道路、河道两旁的线性绿色空间,为正确理解城市环境演变提供了有力的基础。(2)利用1990、2002和2013年亚像元尺度绿色空间信息,构建了RGB植被比例模型。基于RGB加色原理,通过丰富的色彩组合对城市内部绿色空间的细微变化以及区域绿色空间的变化热点进行了可视化表达。结果显示,过去20年,杭州湾地区主要城市区域绿色空间格局发生了剧烈的变化,其中绿色空间的流失主要发生在建成区周边,且2002年后损失更为严重,范围更广。城市中心区域和沿海地区则表现出了绿色空间恢复的趋势。通过对亚像元植被比例进行分级,本文应用景观指数从数量、破碎程度、优势度、聚集度和多样性等方面对城市绿色空间的景观格局在市域范围、老城区和城乡梯度样带三个尺度上进行了研究。市域尺度上绿色空间景观变化反映了城市化对区域环境的影响,总体上经历着以全植被覆盖等级绿色空间为主的景观逐渐退化为无、低和中植被覆盖等级绿色空间景观的过程。强烈的人为活动干扰,尤其是城市建设用地的剧烈蔓延和扩张,切断了原有自然景观在空间上的联系,导致了区域绿色空间景观趋向于破碎化、散布化和无序化。与市域总体变化趋势不同,老城区绿色空间景观改善显著。尤其是2002年以后,零散分布的小斑块绿色空间的增加导致了低覆盖和中覆盖等级绿色空间的增加,逐渐形成网络的城市绿色空间景观将原来大片存在的非透水面分割成较小的斑块,绿色空间景观多样性增强。老城区的绿色空间景观格局变化特征反映出了城市发展和绿化政策对城市核心区域环境的影响。尤其是第二个时期新的绿化政策和创新的绿色空间增长策略,极大地促进了中、低植被覆盖绿色空间在数量和空间分布上的增长,对改善城市内部环境起到了积极的效果。梯度分析进一步揭示了绿色空间景观格局随建成区扩张的时空变化特征。(3)基于人口普查数据,采用基尼系数和泰尔指数对2000年和2010年绿色空间和公共公园与人口在街镇尺度上的空间匹配性进行了研究。随着城市化的推进,绿色空间与人口的不匹配性加剧,而公共公园与人口之间不匹配性则显著减小。在规模较大的城市,绿色空间的不匹配性超过公共公园,成为区域不匹配性的主要问题。在城市和乡镇之间,城市组内部的绿色空间不匹配性要更为严峻,并且城乡之间在绿色空间的获取上差异显著。相比较而言,公共公园的不匹配性主要来自乡镇组内部。由于近年来公园建设的进展,尤其是社区公园和农村公园的建设,乡镇组内部的不匹配性以及城乡之间的差异均得到改善。绿色空间和公共公园的获取上,老龄人口内部存在更大的差异,而外来人口内部则差异较小,这种差异主要是由于外来人口和老龄人口的空间集聚特征所致。通过分别计算城市组和乡镇组不同人口组别的人均绿色空间面积和公共公园面积,清晰地反映出城市居民,尤其是老龄人口,在绿色空间和公共公园获取上存在巨大的城乡差异。而外来人口虽然内部差异较小,但其整体相对于普通居民在公共公园的获取上处于劣势。未来城市绿色空间规划应坚持以人为本的原则,充分考虑不同群体的需求特点,实现环境资源的有效配置及公正分配。快速城市化对区域城市绿色空间景观影响是深远而复杂的。快速增长的人口和繁荣的经济活动刺激着城市对土地的需求,对城市内部及周边绿色空间造成巨大压力。同时,环境保护意识的增强和绿化理念的进步也可能为城市绿色空间带来更加完善的布局和管理。多尺度上研究城市绿色空间对城市化作用的时空响应机制,有助于理解城市环境的现状及其演变规律。基于亚像元的绿色空间信息提取以及景观分析方法,可以获得传统分析方法难以提取的时空演变以及景观格局信息,为Landsat等中等分辨率遥感影像在城市景观生态研究中的应用提供了一个新的思路。
[Abstract]:With the improvement of the living standard, the urban residents have made higher demands on the urban environment. The study on the spatial and temporal change of the green space of the city can deepen the understanding of the evolution of the urban environment in the context of the rapid urbanization, and provide guidance for realizing the rational distribution of the green space of the city and promoting the full play of the ecological benefit and the social benefit. The spatial and temporal resolution of the remote sensing data source and the information extraction method of the remote sensing data source are made higher. Based on the Landsat image as the main data source, the temporal and spatial dynamics of the urban green space and the change of the landscape pattern of the urban green space in the six major cities of Hangzhou Bay have been studied by using the urban green space information extraction and change detection method based on the sub-image elements. The spatial matching and environmental justice of the urban green space and the public park and the population distribution are further analyzed in the street town scale. The main research contents and conclusions are as follows: (1) The regional green space information extraction method based on the multi-terminal spectral hybrid analysis is adopted, and the urban green space information of the major cities of Hangzhou Bay City,1990,2002 and 2013 is extracted at the sub-pixel level. Firstly, a threshold method is adopted to perform a pure vegetation mask on the image, so that the calculation amount of the model and the interference caused by the fine change of the vegetation spectrum of the pure vegetation cover area are effectively reduced. By adding the water body and the shadow end element in the traditional VIS model, the green space information of the wetland, the farmland water network and the periphery of the water body in the city can be better extracted in the typical Jiangmen Township, which is characterized by water-green symbiosis. In addition, when the end-element spectrum of the different complex horizontal model is determined, the three-terminal element and the four-terminal element model are operated by selecting the appropriate end-element spectrum by the view of the operation result of the two-terminal element model, and the operation efficiency can be improved while the accuracy is ensured. The results show that the regional green space information extraction method based on the multi-terminal spectral hybrid analysis can extract the urban green space information more accurately, in particular the small plaque green space and the road, the linear green space on both sides of the river channel, It provides a powerful foundation for understanding the evolution of the urban environment. (2) Using the sub-scale green space information of 1990,2002 and 2013, the RGB vegetation proportion model was constructed. Based on the principle of RGB color addition, this paper makes a visual representation of the fine change of the green space in the city and the change of the regional green space through the rich color combination. The results show that in the past 20 years, the green space pattern of the major urban areas in the Hangzhou Bay area has changed dramatically, and the loss of green space mainly occurs in the periphery of the built-up area, and the loss is more serious and the scope is wider in 2002. The urban central region and the coastal area show the trend of green space recovery. By grading the proportion of the sub-image elements, the landscape pattern of the urban green space is studied from the aspects of quantity, degree of fragmentation, dominance, degree of aggregation and diversity. The change of the green space landscape on the scale of the market reflects the influence of the urbanization on the regional environment. The strong man-made activity disturbance, especially the severe spread and expansion of the urban construction land, cut off the link between the original natural landscape and the space, and led to the tendency of the green space of the region to break, spread and disorder. The green space landscape in the old city is improved significantly, according to the overall trend of the market. in particular, after 2002, the increase of the green space of the scattered small plaque leads to the increase of the green space of the low covering and middle covering grade, gradually forms the urban green space landscape of the network, and the non-permeable water surface existing in the original large area is divided into smaller patches, And the landscape diversity of the green space is enhanced. The change of the green space landscape pattern in the old city reflects the influence of the urban development and the green policy on the urban core environment. In particular, the new greening policy and the green space growth strategy of the second period have greatly promoted the growth of the green space in the medium and low vegetation covering the quantity and the space distribution, and has a positive effect on the improvement of the internal environment of the city. The temporal and spatial variation of the green space landscape pattern with the built-up area is further revealed by the gradient analysis. (3) Based on the census data, the spatial matching of the green space and the public park and the population on the street town scale was studied by using the Gini coefficient and the Teri index. With the development of urbanization, the mismatch between the green space and the population is increasing, while the mismatch between the public park and the population is significantly reduced. In large-scale cities, the non-matching of green space exceeds the public park, and becomes the main problem of regional non-matching. In the urban and rural areas, the green space in the urban group is not matching, and the difference between urban and rural areas in the green space is significant. In contrast, the non-matching of the public park is mainly from the inside of the town group. The development of park construction in recent years, in particular the construction of community parks and rural parks, the non-matching within the township and the differences between urban and rural areas have been improved. In the acquisition of green space and public park, there is a greater difference in the old population, and the difference in the inside of the foreign population is smaller, which is mainly due to the spatial agglomeration of the foreign population and the old population. By separately calculating the green space area and the area of the public park of different population groups in the city group and the town group, it is clear that the urban residents, especially the old population, have huge urban and rural differences in the green space and the public park. While the internal difference of the foreign population is small, the whole population is at a disadvantage with respect to the general population in the acquisition of the public park. In the future, the green space planning of the city should adhere to the principle of people-oriented, give full consideration to the needs of different groups, and realize the effective allocation and fair distribution of the environmental resources. The impact of rapid urbanization on the green space landscape of the regional cities is far-reaching and complicated. The rapid growth of the population and the prosperity of the economy has stimulated the city's demand for land, causing great pressure on the city's interior and surrounding green space. At the same time, the improvement of environmental protection consciousness and the progress of the green idea may bring more perfect layout and management to the green space of the city. The spatial and temporal response mechanism of the urban green space on the urbanization is studied in a multi-scale, which can help to understand the present situation and the evolution law of the urban environment. Based on the green space information extraction and the landscape analysis method of the sub-image element, it is possible to obtain the space-time evolution and the landscape pattern information that the traditional analysis method is difficult to extract, and provides a new idea for the application of the medium-resolution remote sensing image such as Landsat in the urban landscape ecological study.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU982.2

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