臺北盆地的熱環境特徵與都市綠色基盤的影響

Thermal Environments of Taipei Basin and Influence from Urban Green Infrastructure

本研究以LANDSAT 8衛星影像探討臺北盆地內地表溫度的分布特徵以及綠色基盤度對此特徵的影響。結果顯示熱島產生的地點多位於新北市境內，多有大面積、高密度、連續不透水面的開發特徵，而冷島則多產生在有較大水體或綠地混合的地點。地表溫度受到地表覆蓋類別的影響，水體、樹木、草地的覆蓋地點均呈現相對低溫，但水體的涼化強度最高，其次是樹木。涼化效應的空間分布受到綠色基盤的空間紋理以及其周遭地區溫度的影響，在具有大型綠地與水體的地點，若緊鄰地區沒有其他高溫熱源，則較容易觀察冷島與涼化擴散的現象。據此，本研究建議在擬定臺北盆地的降溫策略時，應整合考量綠色基盤與周遭建成環境間的相互關係，透過1.保護既有冷島；2.增加綠地內部樹木與水體的面積；3.降低綠色基盤周遭地區的溫度…等規畫設計原則，應能提升既有綠色基盤的涼化強度與穩定度，並促使涼化效應向外延伸擴展。

Thermal distribution patterns and the influence of green infrastructure in Taipei Basin were analyzed using LANDSAT 8 satellite imagery. The image analysis results showed that most heat islands are distributed within New Taipei City, where they are characterised by densely built areas and/or large and continuous impervious surfaces; whereas cool islands are mostly associated with areas that are mixed with large water bodies and vegetated grounds. Land surface temperature is significantly influenced by land cover, with areas covered by water, trees, and grasses having relatively low temperature. Water body is the coolest land cover type, which is followed by trees. The spatial distribution of the cooling effects is affected by the pattern of green infrastructure and the temperature of its surroundings. Cool islands and cooling dispersal tend to occur in areas mixed with water and greenspaces, which are not adjacent to hotter surroundings. Accordingly, this study suggests integrated consideration of green infrastructure and its interrelationship with surrounding built environments when developing a heat mitigation strategy for Taipei Basin. This can be achieved through planning and design principles including: preserving existing cool islands, increasing water and tree coverage inside greenspaces, and mitigating temperature at the surroundings of green infrastructure. These actions may enhance the cooling magnitude and stability of existing cool islands and facilitate cooling extension in Taipei Basin.