北京城区绿地防灾避险功能评估

城市绿地具有重要的防灾避险功能。以北京城区具有防灾避险功能的绿地为研究对象, 划定了不同类型绿地的防灾避险服务半径, 利用ArcGIS的缓冲区分析工具, 对研究区内绿地 的防灾避险服务范围进行了分析。结果表明:绿地防灾避险有效服务面积占研究区的 71.22%,3.94万hm²的区域处于服务盲区, 主要分布在五环路以外的海淀、丰台和朝阳区; 从防灾避险绿地和服务范围的覆盖率来看, 西城区>东城区>朝阳区>石景山区>海淀区> 丰台区, 有111个街道、地区办事处和乡镇覆盖率在90% 以上, 但仍有占研究区面积 24.08%的办事处和乡镇覆盖率在80%以下;此外, 防灾避险绿地及服务区覆盖率由市中心向 外围呈现递减趋势。

Analysis of the disaster prevention and reduction functions of urban green spaces in Beijing City

Urban green spaces can play an important role in disaster prevention and reduction, which has aroused more attention.This paper selected the green lands with function of disaster prevention and reduction in six districts of Beijing city as case studies.The service radius of different types of green spaces was calculated on the basis of corresponding relationship between disaster prevention systems and different types of urban green spaces.And the radiation range of green spaces in different districts,streets and towns were analyzed with the aid of ArcGIS buffer tool.The results showed that the effective service area accounted for 71.22% of the total area,and there was a blind area of 39377.3hm²,mainly distributed outside the Fifth Ring Road.The coverage rate of service areas was ranked in a descending order of Xicheng District,Dongcheng District,Chaoyang District,Shijingshan District,Haidian District and Fengtai District.The coverage percentage was above 90% in 111out of 130 blocks and towns,whereas the ratio was below 80% in 24.08% of the area.Wangzuo town in Fengtai District and Sujiatuo town in Haidian District had lower coverage rates of service areas,being 44.6% and 46.6%,respectively. The coverage of green space and buffer zones from the city center to the periphery showed a decreasing trend.