植被指数与杭州市热岛效应的关系研究

Studies on the Relationship between Vegetation Index and Urban Heat Island Effect

城市热岛效应一直备受城市规划者关注,植被对城市热岛的影响是绿地规划的基本依据。本文利用杭州市1994年和2004年两个时相的TM影像,生成热岛分布图、归一化差值植被指数(NDVI)图。同时利用GIS的变化分析,直观地显示了十年来杭州市城市热岛效应和城市绿地的分布变化。研究表明,城市热岛的范围随城市扩张而增大,2004年高温区、较高温区的面积比1994年分别增加了29.6%和31.3%。1994年杭州市热岛集中在城中心,到了2004年,热岛范围已由城中心向杭州市西北部、北部和东部扩张;发现NDVI变化与热岛分布变化有很大的关联,并且NDVI值与热岛效应(亮温)呈极显著负相关。上述结果对城市绿地规划和缓解城市热岛效应具有较好的指导意义。

Urban heat island（UHI） effect has been concerned by urban planners because of its importance in the green space planning,The LandSat-5 TM images in 1994 and 2004 were used in this study to create UHI maps,normalized difference vegetation index （NDVI）maps.Spatial changes of UHI and NDVI between 1994 and 2004 were also analyzed using GIS change analysis.Results showed that areas of UHI significantly increased with the development of Hangzhou City. The areas of high temperature and sub-high temperature places increased by 29.6% ＆ 31.3% from 1994 to 2004, respectively.During the same period, UHI expanded from center of the City to east,north and northwest areas. It was found that NDVI was negatively correlated with UHI（P〈0.05）. These results would be significant for guiding urban green space planning and depressing UHI effect,