在当前快速城镇化背景下,大量城镇人口导致各大城市人口密度不断增加,高密度的城区热岛现象开始加剧。公园绿地作为城市生态系统的重要组成部分,在缓解热岛方面具有重要作用。本研究以天津中心城区8处较大的公园绿地为实证对象,基于2013年Landsat8 ETM+影像,通过单窗算法分析其降温效应。研究表明:公园面积及植被覆盖度是热岛效应最重要的影响因子,水体比例也在很大程度上影响着地表温度;各公园的最大降温强度和降温距离差异较大,降温强度温差约2.72℃,降温距离相差195 m;城区面积较大的公园降温效应更明显,水体比例高于30%或植被覆盖度高于10的公园降温效应较理想;并在研究结论的基础上构建了公园的降温效应模型。研究成果为天津中心城区及类似高密度城区的公园绿地规划提供了有效技术支撑。

Rapid urbanization results in the increase of population density of large cities. And urban heat island effect becomes severe. Park green spaces, as an important component of the city ecosystem, play a significant part in alleviating heat island. We choosed 8 large parks of Tianjin center city as empirical objects, used single window algorithm and analyzed their cooling effect based on Landsat8 ETM+image in 2013. The results show that the coverage areas of the parks and vegetation coverage ratio are the most important factors influencing the urban heat island effect, and also water ratio has a great influence on the surface temperature. The maximum cooling intensity and cooling distance of the 8 parks differ largely with each other. The cooling intensity temperature difference is about 2.72℃ and the cooling distance is 195 m. Parks with larger area has more obvious cooling effect, especially when the water ratio is higher than 30% or the vegetation coverage higher than level 10. A model of Parks' cooling effect is deducted based on the conclusion of the study. The results of the research provides effective technical support for the planning of park green space in Tianjin center city and similar high density urban areas.

国家自然科学基金资助项目(51278330);国家留学基金委项目"健康城镇化"(留金欧[2013]6004号)。