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利用MODIS资料研究了2004年4月南京城市热岛特征及其影响因子,结合地表覆盖类型分析了植被归一化指数(Normalized Difference Vegetation Index,NDVI)、地表温度(Ts)、地表反照率(α)的城乡差异及其相互关系,探讨了城市热岛(Urban Heat Island,UHI)效应形成的机制。结果表明:南京城区存在着明显的城市热岛效应;城市平均Ts比乡村高约10.83%;城市NDVI和α分别比乡村低约为62%和18.75%;NDVI与Ts呈负相关,相关系数为-0.73,而NDVI与α之间关系与波段有关;城乡植被覆盖差异是造成UHI的主要原因,其次是地表反照率,通过提高植被覆盖率和地表反照率可以减小城市热岛效应。
MODIS data were used to study the characteristics of urban heat island in Nanjing in April 2004 and its influencing factors. The NDVI (Vegetation Normalization Difference Vegetation Index), surface temperature (Ts), surface albedo (α) The differences between urban and rural areas and their interrelationships, and discusses the mechanism of Urban Heat Island (UHI) effect. The results show that there is obvious urban heat island effect in urban area of Nanjing; urban mean Ts is about 10.83% higher than that of rural areas; urban NDVI and α are respectively about 62% and 18.75% lower than rural areas; NDVI is negatively correlated with Ts and the correlation coefficient is - 0.73, while the relationship between NDVI and α is related to the band. The difference of urban and rural vegetation cover is the main cause of UHI, followed by the surface albedo. The urban heat island effect can be reduced by increasing the vegetation coverage and surface albedo.