城市三维景观格局与热舒适度关联分析：响应与调控

The rapid urbanization process is characterized by significant landscape modification, which can lead to serious environmental problems such as the deterioration of the outdoor thermal environment. Studies on the relationships between urban thermal environment dynamics and associated landscape patterns are fundamental to understand the evolution mechanisms of urban thermal environment and propose landscape optimization strategies. It is thus important to accurately depict the highly complicated urban landscapes and quantify the effects of its correlated thermal environment on urban residents. Firstly, we collect several landscape metrics which have definite physical meanings and are straight forward to compute numerically. Secondly, association analysis between these two and three-dimensional landscape metrics and outdoor comfort levels obtained by combining filed observation in situ and questionnaire investigation is applied to select the key landscape metrics that highly sensitive to the changes in thermal environment. Thirdly, a numerical model is used to further study the relationships between landscape patterns and outdoor thermal comfort levels. Finally, two main purposes are expected to achieve: 1) the study area is classified into zones with different comfort levels; 2) we can propose corresponding landscape optimization strategies especially for regions under strong heat stress. Taking three-dimensional landscape metrics and thermal comfort levels as the main research objects can provide useful insights on revealing the interrelation among landscape patterns, ecological processes and ecological functions, as well as a new path to guide decisions in people oriented urban environment management and planning targeted to improve urban thermal environment.

城市化的快速发展使得城市地区景观格局发生深刻变化，导致城市热环境恶化等诸多环境问题。明确城市景观格局与热环境效应之间的响应关系，对深入理解热环境的发展机制和面向热环境改善的景观格局优化具有重要意义。如何准确刻画高度复杂的城市景观格局，同时定量评价其热环境效应对城市居民的影响是问题的关键所在。本研究选取具有明确物理意义的三维景观指数，辅以热环境研究常用二维景观指数，构成备选景观指数群组，与通过实地检测和问卷调查获得的监测点热舒适值进行关联分析，遴选对局地热舒适程度敏感的关键景观指数，然后利用微气象模型设置梯度情景进一步分析二者之间的响应关系。基于这种响应关系，借鉴城市环境气候图编制方法，实现城市尺度上的热舒适度分级和分区，并针对受热胁迫较强分区给出景观格局优化方案。本研究有助于对城市景观“格局-过程-功能”关系的深入理解，也为“以人为本”的城市热环境调控提供新路径。

城市化的推进导致城市地区的景观格局发生了深刻变化，形成热岛效应并影响人群健康。明确城市的景观格局与热环境之间的响应关系，对于深入理解热环境的形成及其缓解机制具有重要意义，也是本研究旨在解决的主要问题。在前期数据和经验积累的基础上，通过执行期间的持续研究，产生如下研究成果：（1）构建了用于评估到达城市表面太阳入射辐射能量密度的景观指数，该指数可用于分析在城市发展过程中建筑景观格局变化所导致的太阳入射辐射能量在城市表面的重新分配，可用于指导绿地水体等景观组分的布设；（2）在街区尺度上初步确定了绿地覆盖率增幅与近地表气温降幅之间的非线性关系，可用于确定在街区尺度上绿地布设的最低比例；（3）对城市热环境研究中常用的指数（天空可视角）进行改进，形成具有明确生态环境意义的新型指数（太阳可视角），该指数可用于分析不同景观组合内的热环境或者热舒适的优劣程度；（4）发展了一个基于城市功能分区的热环境调节的分析框架。该框架适用于不同类型城市，它以同一类型功能区内热环境表现较为优秀的斑块为样板，对于表现较差的斑块进行适当的景观格局优化，最终达到在整个城市尺度上的热环境的缓解。本课题完成了各项研究任务并开展了深入的国内外合作交流，在项目资助下发表英文论文5篇，中文论文1篇。