摘要
利用2006年和2010年8月的TM卫星影像,通过定量遥感反演手段和相对亮温分析方法,反演和分析了西安市城区相应时间点上的热场温度。结果显示:其城区平均气温由2006年的26.28℃提高到2010年的28.14℃,5 a间升高了1.86℃。期间高温区域在市区的西部、西南部和东南部出现了较大范围的扩展,尤其以东南部的扩展范围和强度为大。从相对亮温情况来看,全市缺乏极强热岛,整个市区以弱热岛占绝对优势,2010年和2006年其面积比例分别为61.11%和58.64%;其次为绿岛,其面积比例在2010年和2006年分别为34.08%和35.98%;中等热岛和强热岛所占比例极小。绿岛面积减少的最大区域在西北部的汉长安城遗址南部以及市区东南部的三兆、东伍一带;而强热岛在2010年呈星点状分布在东郊的灞桥纺织城、西二环附近的西安电工铸造厂和西安电压力容器厂、长安区的河池寨等地。从相对亮温热力斑块的转移概率矩阵看,最稳定的热力景观斑块类型为弱热岛斑块和绿岛斑块,2006—2010年,其保持不变的面积分别达79.41%和67.82%;而最不稳定的景观类型为中等热岛和极强热岛,其发生变化的面积比例分别为70.73%和64.18%。从西安市区热场变化的原因来看,城市建设的影响最大,其中人口增长、建成区范围扩张和房地产开发是最主要的影响因素,另外全球变化背景下的区域气温升高也是西安市热岛效应加剧的另一促进因素,而城市绿化建设可以在一定范围内改善局地的热岛效应状况。
Urban heat island effect is a very common and serious problem in modern city. It affects not only the quality of urban environment, but also the daily life of citizen. There are generally two methods to study it. One is to compare the meteorological data from the weather stations located in a zone between city and rural area, and an- other .:s to analyze the remote sensing images. Xi 'an is a very important city in west China. In recent 30 years, many environment problems were resulted in along with the rapid urbanization, such as the reduction of farmland, soil and air pollution and urban heat island effect. In this paper, a case study was carried out in Xi 'an City so as to retrieve the values of relative brightness temperature from Landsat TM thermal-infrared data ( August 9, 2006 and August 4, 2010). The stability of relative brightness temperature during the period from 2006 to 2010 was analyzed according to the transition probability matrix of relative brightness temperature. The results showed that the brightness temperature intensity in Xi 'an City was increased during the period from 2006 to 2010. The mean surface temperature was 26.28 ℃ in 2006, but was increased to 28.14 ℃ in 2010, and the increase occurred mainly in the western, southwestern and southeastern parts of Xi'an City. Based on the results of the relative brightness tempera- ture, it was found that the extremely heat island effect did not occur in 2006 and 2010, the slight heat island effect was dominant, and the proportion of area of the patches with slight heat island effect was 61.11% and 58.64% in these two years respectively. The proportion of area of green islands was secondary, and it was 34.08% and 35.98% in 2006 and 2010 respectively. From the view of landscape ecology, stability of the patches with slight relative brightness temperature and of the green island patches was the highest. The stability of patches with moder- ate and severe relative brightness temperature was the lowest. It was considered that climate change and urban construction were the main reasons causing a dynamic change of surface heat regime. Urban green land could reduce the urban heat island effect.
出处
《干旱区研究》
CSCD
北大核心
2013年第2期347-355,共9页
Arid Zone Research
基金
国家科技部"十二五"科技支撑项目(2011BAD38B03)
关键词
热岛效应
TM影像
遥感反演
亮温
热力景观
西安
urban heat island
Landsat TM image
remote sensing inversion
brightness temperature
thermal landscape
Xi 'an