Estimation of the relationship between vegetation patches and urban land surface temperature with remote sensing

It is well known that vegetation has cooling effect on urban land surface temperature (ULST). However, the influence of vegetation's structure, component, and spatial distribution on ULST has rarely been quantitatively studied. This paper, taking Landsat ETM+ data to retrieve ULST, and IKONOS data to obtain vegetation information, studied the relationship between ULST and vegetation patches. Results showed that in the urban environment, (1) ULSTs over tree and shrub, lawn, and weed patches were not much different, because of the edge effects of the vegetation patches and their fragmentized distribution pattern; (2) the relationship between ULST and area, perimeter, and shape index of vegetation patches exhibited positive, while LST and the ratio of perimeter/area presented negative linear relationship; (3) using land use polygons as units, area density had quadratic curve relationship to ULST, edge density and mean area density, had strongly negative relationship to ULST. These results indicated that not only the characteristics of vegetation patches, but also their spatial distribution had a great effect on ULST, which should be considered in urban ecological environment management.