关键词: 遥感, 土地利用, 景观格局指数, 热环境

Abstract:

One of the significant environmental consequences of urbanization is the urban heat island (UHI), which is associated with underlying land surface types and land use patterns. Selecting Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data of Suzhou City obtained on 1986 and 2006 separately, the paper used the maximum likelihood classification method to extract underlying surface types based on raw visual and near infrared bands, normalized difference vegetation index (NDVI), modified normalized difference water index (MNDWI) and digital elevation model (DEM) data. Then landscape pattern indices changed with different grain sizes were discussed and its variation characteristics were analyzed within the optimum grain size. Furthermore, land surface temperature (LST) was retrieved from thermal infrared bands by an emissivity-modified model and then it was used to get distribution of thermal field variance indices. Lastly the paper discussed the relationship between changes of landscape pattern indices and variation of thermal environment. Research results show that landscape pattern indices depend on grain size clearly, the most appropriate spatial grain size is from 120 m to 150 m. There is an evident development of the UHI, combined with year 1986, thermal field variance index increase in 2006 as a whole. Fragmentation degree, the shape complexity of the patches and landscape diversity increase while the clustering degree decrease, and furthermore the landscape pattern indices change more clearly in regions where the thermal field variance indices increase, which indicate that change of underlying surface pattern has an effect on local thermal environment.

Key words: remote sensing, land use, landscape pattern indices, thermal environment