Visualization of solar shading effect by trees in urban areas

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K18169
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Architectural environment/Equipment
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Kumakura Eiko 首都大学東京, 都市環境科学研究科, 助教 (90716135)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 樹木 / 日射遮蔽効果 / 都市熱環境 / 対策マップ

Outline of Final Research Achievements

In order to provide a visualization of the solar shading potential from trees on the map in urban areas, the thermal environment for the morning commuting hours in summer was measured by bicycle with equipment and simulated. The air temperature and the mean radiant temperature (MRT) were measured and analyzed according to road directions on the marathon course for the Tokyo 2020 Summer Olympics as representative urban blocks. The 13 typical blocks in the road were simulated. The relationship between the percentage of shade on the sidewalk and the MRT was analyzed. The solar shading effect of trees was up to about 40% of the sidewalk area, and the minimum of that was 0% despite having trees. Based on the percentage of shade on the sidewalk, the MRT, and the air temperature difference, a thermal environment countermeasures map for the blocks was created.

Free Research Field

都市・建築環境工学

Academic Significance and Societal Importance of the Research Achievements

都市の緑は、街路樹や空地に積極的に取り入れられており、今後も増加することが期待されているが、その物理的な効果を定量評価する研究は少ない。本研究は、夏季の通勤時間帯における歩道に対し、樹木の日射遮蔽効果が高い場所を抽出・分類し、地図上に可視化したものである。実測により、道路幅、建物高さ、道路方位によって熱放射環境が似た傾向であることを把握した上で、それぞれに対し、シミュレーションによって樹木の日射遮蔽効果による対策方法を分類した。樹木の日射遮蔽効果を実際の街区へ導入する方法に関する情報は、快適性に配慮した都市緑化の際に役立つものと考える。