热环境视角下的最小生态安全距离——以大连北三市为例

The minimum distance for ecological security from perspective of the thermal environment: the case of three northern districts of Dalian

随着2014年国家环保部首次提出了“最小生态安全距离”的概念,城市内部与城市间的生态安全逐渐受到社会重视,而且基于热环境的最小生态安全距离也逐渐成为人们关注的焦点。基于热环境视角下最小生态安全距离的实质内涵,结合遥感影像、行政边界、建成区边界,利用高斯混合模型及热岛信号函数,对 2013 年至 2016 年大连市北三市的热岛面积及最小生态安全距离进行测算。研究表明,2013年至2016年间,大连市北三市的城市热岛总面积已由694.10km^2扩张到1864.30km^2。同时,普兰店市与瓦房店市之间的最小生态安全距离由 8.70 km 衰减至-3.10 km,热环境出现叠加情况,相对危险。而普兰店市与庄河市之间的最小生态安全距离,由 73.47 km 衰减至 58.24 km,热环境未出现叠加情况,相对安全。总体上呈现出城市热岛面积逐渐扩张趋势,城市间最小生态安全距离逐渐衰减的趋势。

With the concept of "the minimum distance for ecological security" first proposed by The Ministry of Environmental Protection in 2014, the ecological safety within and between cities has been paid increasing attention to by society, while the minimum distance for ecological security based on the thermal environment has gradually become the focus of people's attention. Based on the essential connotation of the minimum distance for ecological security from the perspective of thermal environment, combined with remote sensing image, administrative boundaries, and the boundaries of built-up areas, this paper uses the Gaussian mixture model and heat island signal function to calculate the area of the heat island and the minimum distance for ecological security in the three northern districts of Dalian from 2013 to 2014. The research shows that the total area of the urban heat island in the three northern districts of Dalian has expanded from 694.10 km^2 to 1864.30 km^2. At the same time, the minimum distance for ecological security between Pulandian and Wafangdian decreased from 8.70 km to -3.10 km, resulting in the superposition of thermal environment, which was relatively dangerous. However, the minimum distance for ecological security between Pulandian and Zhuanghe decreased from 73.47 km to 58.24 km, and the thermal environment did not appear to undergo superposition, which was relatively safe. Overall, the urban heat island area gradually expanded, and the minimum distance for ecological security between cities gradually decreased.