The role of local land-use on the urban heat island effect of Tel Aviv as assessed from satellite remote sensing
The role of local land-use on the urban heat island effect of Tel Aviv as assessed from satellite remote sensing
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DOI：
10.1016/j.apgeog.2014.11.023
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发表时间：
2015
影响因子：
4.9
通讯作者：
Orit Rotem-Mindali;Yaron Michael;D. Helman;I. Lensky
中科院分区：
文献类型：
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作者：
Orit Rotem-Mindali;Yaron Michael;D. Helman;I. Lensky
在过去的几十年里，城市的气候变化受到了极大的关注。城市地区的热应激对人类健康有不利影响，而且由于全球变暖，预计未来还会恶化。植物已被证明可以缓解这种影响，但将“绿色”区域引入大都市空间是一项具有挑战性的任务。我们根据特拉维夫的地表温度评估了热负荷，特拉维夫是以色列最大的大都市区。对四种不同的城市土地利用方式的热效应进行了估算。具体地说，我们比较了植被覆盖率较高的住宅区(这里指的是绿色住宅区)与中小型(2-40公顷)公园的降温效果。为此，我们使用陆地表面温度(LST)和归一化差异植被指数(NDVI)的卫星数据作为植被覆盖的替代。将高时态数据与高空间分辨率数据相结合，生成特拉维夫高空间分辨率的10年平均LST和NDVI图。正如预期的那样，由于植被与自由空间面积的比率最低(1%)，工业区的LST最高，而绿色地区的LST最低。绿色住宅和中小型公园的热负荷相当，绿色住宅的LST略低(降低0.5摄氏度)。总体来说，中小型公园的地表温度高于预期。对植被自由空间的低效利用，即相对较低的植被覆盖率与自由空间比率，可能是造成这种情况的主要原因。公园具有较高的局部降温效果，但对邻近地区(距公园30-90米)的降温效果较差，这可能是由于它们在城市结构中的相对位置。我们的结果表明，应该鼓励在私人城市空间内的绿化区域，而不是在缺乏足够的自由空间来容纳较大公园的大都市地区新建中小型公园。这项研究的结果可能对城市规划者在现有密集城市布局的限制下寻求缓解城市热岛效应具有重要意义。
Climate change in cities has received much focus in the past few decades. Heat stress in urban areas has an adverse effect on human health and is expected to worsen in the future due to the global warming. Vegetation has been shown to mitigate this effect, but introducing ‘green’ areas into the metropolitan space is a challenging task. We assessed the thermal load in terms of surface temperature in Tel Aviv, the biggest metropolitan area of Israel. The thermal effect of four different urban land uses was estimated. Specifically, we compared the cooling effect of residential areas with high vegetation cover (referred here as ‘green’ residential) to that of small to medium size (2–40 ha) public parks. To this end, we used satellite data of land surface temperature (LST) and the Normalized Difference Vegetation Index (NDVI), as a surrogate for vegetation cover. High-temporal data were combined with high spatial resolutions data to produce 10-year average LST and NDVI maps at high spatial resolution over Tel Aviv. As expected, industrial areas had the highest LST due to lowest ratio of vegetation to free space area (1%), while ‘green’ areas displayed the lowest LST. Green residential and small-medium public parks had comparable thermal loads, with green residential having slightly lower LST (by 0.5 °C). In general, small-medium public parks displayed higher LST than expected. Inefficient use of free spaces for vegetation, i.e., relatively low vegetation cover to free space ratio, was probably the main cause for this. Public parks had a higher local cooling effect, but a less continuous one on the proximate surrounding (30–90 m from the park), probably due to their relative location in the urban fabric. Our results suggest that ‘greening’ areas within the private urban space should be encouraged at the expense of building new small-medium parks in metropolitan areas that lack the sufficient free space for larger parks. The outcome of this study may have key implications for urban planners seeking to mitigate urban heat island effects under the limitation of existing dense urban layout.