基于GIS-PSR的青藏高原河湟谷地城市生态安全测度及时空格局——以海东市为例

ECOLOGICAL SECURITY MEASURES AND SPACE-TIME PATTERN OF EASTERN QINGHAI PLATEAU BASED ON GIS-PSR:A CASE STUDY OF HAIDONG

基于PSR模型,以2003、2008、2013年Landsat TM影像和社会经济两方面的20种数据为数据源,采用AHP-熵权法和综合加权平均法,运用GIS空间分析,实现栅格尺度为30m的海东市各区县2003~2013年生态安全测度与时空格局演化分析。结果表明:时间上,海东市生态安全整体呈"先下降,后上升"的变化趋势;空间上,呈"南北优,东西劣"的基本特征,高值区分布在东北和西南,低值区分布在中部湟水河城镇发展带上,表现出明显的空间差异性与集聚性;各区县生态安全内部差异性大,平安区变化最大,生态安全改善最为明显,乐都区、互助县、化隆县、循化县生态安全较稳定,缓慢上升,民和县最低,是海东市生态安全的重点防范区域;该研究可为构建河湟谷地生态安全格局提供有效途径,为改善河湟谷地城市可持续发展提供依据。

Based on the pressure-status-response(PSR) model, the social and economic statistical data and Landsat TM remote sensing images data of the plateau city-Hai Dong for 2003, 2008, 2013 are taken as the data source in this paper. By using the methods of comprehensive weighted average(WCA), analytic hierarchy process(AHP) and entropy coefficient method, an ecological security evaluation system and the corresponding model are built for this plateau city. Meanwhile, the comprehensive evaluation of the ecological security in the study area can be achieved by combining the GIS spatial analysis technique and the statistical analysis method. All the results indicate that the ecological security rose at the beginning then dropped later in time from 2003 to 2013 in Hai Dong. Meanwhile, the basic characteristic in space is that the ecological security is good in the north and the south and bad in the east and west. Moreover, obvious spatial difference and convergence are shown as the fact that the high-value area of the ecological security is mainly distributed in the northeast and southwest, and the low-value area is mainly distributed in the central of the Huang Shui He-river urban development belt. The inner gap of the ecological security level is obvious in all counties, the improvement of ecological security is most obvious in Pingan, Ecological security is stable and slowly rising in Ledu, Huzhu, Hualong and Xunhua, Minhe is the lowest level of ecological security. This study provided an effective way to assess the ecological security level of urban in Eastern Qinghai plateau and ecological security pattern. The dynamic analysis also provided the evidence for monitoring and improving sustainable development in Eastern Qinghai plateau.