Abstract:
The quality of ecological environment is an important content affecting the livability of cities. By using remote sensing technology, the quality of ecological environment can be evaluated accurately, thus providing a scientific basis for the management and improvement of urban ecological environment. In this paper, four indices were derived from remote sensing images, namely normalized differential vegetation index (NDVI), WET, land surface temperature (LST), and normalized differential building-soil index (NDBSI), which represent greenness, dryness, wetness and heat. These indicators were then coupled through principal component analysis (PCA) and used for establishing an integrated evaluation model named remote sensing ecological index (RSEI), in order to assess the quality of ecological environment in Wuhan, China from 2005 to 2015. The results demonstrate that, during the study period, the area ranked with general or higher levels of RSEI accounts for about 80% in the city, indicating that the overall quality of ecological environment in Wuhan is relatively good with high coverage of vegetation as well as rich biodiversity. In addition, the average of RSEI in Wuhan is 0.60, 0.55 and 0.53 in 2005, 2010 and 2015 respectively, and the proportion of the “excellent” areas of RSEI decreased from 54.40% (in 2005) to 47.63% (in 2010) and then to 42.44% (in 2015). The quality of ecological environment in the whole city has deteriorated along with urbanization; however, such a trend gradually slows down, illustrating that the protection of ecological environment in Wuhan has achieved some positive results. Moreover, spatially speaking, the areas with poor or even lower levels of RSEI are mainly concentrated in the central city, and such areas have been expanding outward along the Yangtze River as well as the Han River, which is consistent with the sprawl direction of construction land from remote sensing images.