摘要
随着城市化的快速发展,城市热岛现象也越来越突出。作为城市生态系统中两种重要的地物类型,园林绿地和水体对城市热岛均有明显的降温效应,因此对其进行定量研究具有重要意义。以桂林市建成区为研究对象,利用TM影像数据提取了区域的地表温度（LST）、植被覆盖度（FV）以及改进的归一化差异水体指数（MNDWI）等生物物理信息,同时借助空间统计和缓冲区分析方法,对区域典型园林绿地和水体地表温度的空间特征及其相关性进行了定量研究。结果表明：桂林市5城区的地表温度以低温区和中温区为主。高温区与极高温区也占有较大比例,两者占市区总面积27.8%,较全市平均地表温度高约2~4℃,整体上呈现显著的热岛效应。城市中园林绿地和水体的平均地表温度分别为26.76和24.86℃。相关性分析揭示,城市园林绿地和水体面积与其内部地表温度呈现极显著负相关关系（sig=0.001）,园林绿地的FV、水体MNDWI则呈显著负相关关系（sig=0.015和sig=0.038）,说明地表温度随着上述参数的增大而降低。除典型水体面积与地表温度的拟合曲线为对数函数之外,其他参数的最佳拟合效果均为线性。缓冲区分析说明,不论是城市园林绿地还是水体,都会对外围一定区域的热环境产生影响。伴随城市园林绿地与水体样区缓冲带距离的增大,外围区域的地表温度呈上升趋势,但这种趋势随距离变化在不断减弱,其有效影响范围在距样区边界120~240 m处。通过对比研究发现,城市中较大面积的公园绿地或水体其降温效应要比面积较小者显著,而水体对于周围热场的影响和敏感度要强于园林绿地。
With the rapid urbanization, urban heat island （UHI） has become more and more serious.Landscape green space and urban water, as the components of city ecosystem, have played an important role in cooling effects.therefore, it has the important theoretical and practical significance to study. This article takes Guilin city as research object, the land surface temperatures（LST）, vegetation fraction（FV）, and modified normalized difference water index （MNDWI） are extracted by using TM image. Then, the paper analyzes the statistical characteristics of the landscape green space and urban water with the spatial statistics and buffer analysis method,and discusses quantitatively the relationship between LST and various parameters. The results show that The low-temperatures and medium-temperatures regions constitute main part of the whole city. The high-temperatures and ultra-temperatures regions occupy partial proportion （27.8%）, which is 2~4 degrees above the mean LST, the UHI effect is obvious in Guilin city. The mean LST of landscape green space and urban water are 26.76 and 24.86 ℃, respectively. Correlation analysis revealed that the LST is significant negatively interrelated with the area of landscape green space and urban water （sig=0.001）, FV and MNDWI （sig=0.015 and sig=0.038）, it can be concluded that high level of these parameters will lead to low LST. The relation between LST and urban water is logarithm function, other parameters are all linear function. Buffer analyses show that both green space and water body have some influence on the thermal environment in peripheral region. Along with the increase of the distance to the boundary, the LST of peripheral region is on the rise, which is weakening, and the distance of influence is 120~240 m away from the boundary of sample regions. Comparative studies show that the cooling effect of a large area of green space or water body is stronger than the small one, and water body play better role in cooling effect than green space.
出处
《生态环境学报》
CSCD
北大核心
2015年第2期278-285,共8页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(41361041)
广西自然科学基金项目(2014GXNSFAA118300)
广西教育厅立项项目(200807LX036)
关键词
TM影像
地表温度
植被覆盖度
改进的归一化差异水体指数
TM images
land surface temperatures
vegetation fraction
modified normalized difference water index
