Small vegetated patches greatly reduce urban surface temperature during a summer heatwave in Adelaide, Australia
Small vegetated patches greatly reduce urban surface temperature during a summer heatwave in Adelaide, Australia
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DOI：
10.1016/j.landurbplan.2021.104046
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发表时间：
2021-05-01
影响因子：
9.1
通讯作者：
Leishman, Michelle R.
中科院分区：
文献类型：
--
作者：
Ossola, Alessandro;Jenerette, G. Darrel;Leishman, Michelle R.
随着全球气候变暖，世界各地的城市面临着更加频繁和极端的热浪。这些事件会影响人类健康并降低宜居性。虽然植被对地表温度 (LST) 的缓解作用在大空间尺度和典型天气条件下得到了很好的表征，但城市绿化在局部尺度上提供的降温效益，特别是在夏季热浪期间，却很少被量化。我们量化了整个城市景观的 LST 变化，以评估极端情况下从土地单位（平均类似于 460 m(2)）到郊区规模（类似于 1.66 km(2)）与土地利用和植被覆盖的关系。夏季炎热条件。在连续三天气温超过 40 摄氏度的热浪事件高峰期，通过安装热成像仪的飞机在澳大利亚阿德莱德 90 个郊区上空飞行，测量了高分辨率 (2 m) 的昼夜地表温度。白天、夜间和昼夜LST分布与郊区和土地单位尺度的土地利用、植被覆盖（即树木、草地）和城市形态相关。在郊区尺度，植被覆盖不影响LST。然而，在土地单位尺度上，树冠覆盖率和较小程度的草覆盖率在白天使当地地表温度降低了 6 摄氏度，但在夜间则没有。土地利用和土地覆盖预测器对总体夜间 LST 的预测效果不佳。从海岸向内陆移动，小植被斑块（主要位于庭院和花园中）与较热的内陆郊区最大的局部LST降低有关。当每个土地单元周围 30 m 缓冲区内存在植被时，白天土地单元内的 LST 进一步降低，这表明对 LST 具有适度的景观降温作用。我们的结果表明，即使是小型城市植被斑块也可以在日益频繁的夏季热浪期间提供显着的缓解热量的作用，特别是在人们居住的住宅环境周围。
As the global climate warms, cities worldwide face more frequent and extreme heatwaves. These events can affect human health and decrease liveability. While the mitigating effects of vegetation on land surface temperature (LST) are well characterised at large spatial scales and during typical weather conditions, the cooling benefits that urban greening can provide at local scales, particularly during summer heatwaves, are poorly quantified.We quantified LST variation across an urban landscape to assess relationships with land use and vegetation cover from land unit (average similar to 460 m(2)) to suburb scale (similar to 1.66 km(2)) under extreme summer heat conditions. High resolution (2 m), dayand night-time LST was measured at the peak of a heatwave event, after three consecutive days with air temperature exceeding 40 degrees C, by flying an aircraft fitted with a thermal imager over 90 suburbs in Adelaide, Australia. Daytime, night-time, and diurnal range LST distributions were related to measures of land use, vegetation cover (i.e., tree, grass) and urban morphology at both the suburb and land unit scale.At the suburb scale, vegetation cover did not affect LST. However, at the land unit scale, tree canopy cover, and to a lesser extent grass cover, decreased local LST by up to 6 degrees C during the day, but not at night. Overall nighttime LST was poorly predicted by the land use and land cover predictors. Moving inland from the coast, small vegetation patches, mostly contained in yards and gardens, was associated with the greatest localised LST reductions in the hotter inland suburbs. LST within land units was further decreased during the day when vegetation was present within 30 m buffers around each land unit, suggesting a moderate landscape cooling effect on LST.Our results suggest that even small urban vegetation patches can be managed to provide substantial heat mitigation during increasingly frequent summer heatwaves, particularly around the residential environments where people live.