Arizona State University, School of Sustainability, Tempe, AZ, USA; Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
Sci Total Environ. 2019 Mar 20;657:904-917. doi: 10.1016/j.scitotenv.2018.11.447. Epub 2018 Dec 3.
The 2020 Olympic Games marathon will be run through the streets of Tokyo on the mornings of August 2nd and 9th, a time of year that is typically hot, sunny, and humid. Few studies have assessed the potential impact of extreme heat along the marathon course to understand the multiple factors (e.g., radiation, wind flow) affecting human thermal comfort (TC) as influenced by urban design and vegetation. The current research establishes a baseline of microclimate conditions and scenarios to estimate the projected TC along the marathon route for spectators. Mobile microclimate data (air and surface temperatures, solar radiation, humidity, wind speed) were collected along the marathon course over 15 periods in the summer of 2016 and aligned with sky view factors (SVF). Human energy budget modeling was applied to provide spatially-explicit heat budget and TC information along the route. Conditions are expected to create the most discomfort along open, sun-exposed locations, with ~50% of the area along the second half of the course resulting in 'Hot' (budget > 200 W m or 'Very hot' (budget > 295 W m) conditions. The heat strain index frequently rises above 80% in these locations, with high humidity and low wind flow exacerbating discomfort. Buildings and trees producing a low SVF over roads and sidewalks protect spectators from the morning radiant heat, but such locations should be balanced with wind flow to optimize comfort. The modeling and spatial information can aid in preparing for and mitigating heat stress during the Olympics. Potential solutions can be implemented in collaboration with local organizers and government. This 'research through design' strategy can aid in preparing for and mitigating heat illness during the Olympics. Knowledge gained can be extended to other areas of Tokyo to reduce urban heat, and further provide targeted guidance for effective environmental cooling techniques for human health.
2020 年奥运会马拉松比赛将在 8 月 2 日和 9 日上午在东京街头举行，这是一年中通常炎热、阳光充足和潮湿的时间。很少有研究评估马拉松赛道上极端高温的潜在影响，以了解影响人体热舒适度 (TC) 的多种因素（例如辐射、风流），这些因素受到城市设计和植被的影响。目前的研究建立了微气候条件的基准，并制定了一些情景，以估算马拉松路线上观众的预期 TC。2016 年夏天，在 15 个时段内，沿着马拉松赛道收集了移动微气候数据（空气和地表温度、太阳辐射、湿度、风速），并与天空视野因子（SVF）对齐。应用人体能量预算模型提供沿途的空间显热预算和 TC 信息。预计在开阔、阳光直射的地点条件会造成最大不适，赛道后半段约有 50%的区域会出现“热”（预算>200 W m）或“非常热”（预算>295 W m）条件。在这些地点，热应激指数经常超过 80%，高湿度和低风流会加剧不适。建筑物和树木在道路和人行道上方产生低 SVF，可保护观众免受早晨辐射热的影响，但这些位置应与风流平衡，以优化舒适度。建模和空间信息可用于在奥运会期间为热应激做准备和缓解。可以与当地组织者和政府合作实施潜在的解决方案。这种“通过设计进行研究”的策略可以帮助为奥运会期间的热疾病做准备和缓解。获得的知识可以扩展到东京的其他地区，以减少城市热，为有效的环境降温技术提供针对人体健康的有针对性的指导。
