快速城市化下银川城市热环境景观格局演变研究

Based on 3 LandsatETM+/TM images of Yinchuan from 1989 to 2011, this paper retrieved land surface temperature (LST) by Qin's mono-window algorithm, and on above basis, landscape metrics were utilized here to analyze the evolution and spatial distribution of urban thermal landscape pattern of Yinchuan city under rapid urbanization in last 20 years. The results showed that: (1) With the development of urbanization, urban thermal landscape pattern of all built districts jointed as a whole. Because of rational urban planning, there existed low-grade thermal landscape patches, cool island and weak heat island, in the centre of main built district, which improved the ecological environment of built district; (2)At class level, the low-grade thermal patches (cool island) and high-grade thermal patches (strong heat island and the strongest heat island) had area reduction, and urban thermal landscape pattern had a tendency to change into moderate heat island and weak heat island. Change of patch density (PD) and edge density (ED) had a similar trend, which verified the change of the aggregation index (AI). All thermal patch types mainly tended to be more fragmented from 1989 to 2000, more aggregated from 2000 to 2011, and patches shape tended to be simplified; (3)At the landscape level, urban thermal landscape pattern saw a turning point in 2000：urban thermal landscape pattern was more fragmented from 1989 to 2000, but, it became more aggregated and patches shape tended to be simplified from 2000 to 2011. Each grade of urban thermal landscape became even-distributed. (4) In the aspect of thermal patches transition, under the influence of human intervention, cool island was the stablest urban thermal patches; The low-grade thermal patches were easy to transfer among themselves, but they were difficult to transfer to high-grade thermal patches; Moderate heat island was easy to transfer to the low-grade thermal patches or higher level thermal patches; The high-grade thermal patches were easy to transfer among themselves, but they were difficult to transfer to low-grade thermal patches.