Analysis of Urban Heat Island in Kochi, India, Using a Modified Local Climate Zone Classification
Analysis of Urban Heat Island in Kochi, India, Using a Modified Local Climate Zone Classification
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DOI：
10.1016/j.proenv.2014.09.002
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
George Thomas;A. Sherin;Shareekul Ansar;E. Zachariah
中科院分区：
文献类型：
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作者：
George Thomas;A. Sherin;Shareekul Ansar;E. Zachariah
城市热岛（UHI）是衡量城市化地区和邻近农村地区之间近地表空气温度差异的一种措施，是城市化最明显的影响。“城市”的定义在不同的背景下有所不同，这使得不同地区的城市之间难以直接比较。采用基于局部气候带（LCZ）分类的方法，在印度南部的高知县研究其城市热岛。2011年1月至2013年3月进行了12次移动的调查，以量化城市热岛强度。黎明前的城市热岛强度大于清晨，冬季的城市热岛强度大于夏季。冬季观测到的城市热岛在黎明前和夜间分别为4.6°C和3.7°C.根据标准区域属性，将研究区划分为10个不同的地方气候区。计算了不同区域之间的温度梯度和在这些区域中观察到的冷却速率，这验证了LCZ分类。最大强度出现在覆盖城市中部的紧凑型中高层区域。最强烈的冷却观察到在开放和稀疏建造的地区在所有季节。单靠标准带的性质不足以解释同一等级不同表面积和不同相邻带的城市热岛强度的变化。另外两个区域属性，称为区域边界距离的相邻区域的径向距离和最近相邻区域，在这里提出来克服这个问题。这些附加参数的使用给出了一个更好的理解区域内变化的城市热岛强度的相同类别与不同的覆盖面积和不同的相邻区域。
Urban Heat Island (UHI), a measure of the near surface air temperature contrast between urbanised and adjoining rural areas, is the most pronounced effect of urbanisation. The definition of ‘urban’ varies in different contexts, which makes it difficult for direct comparison between cities in different regions. Local climate zone (LCZ) classification based method was adopted in Kochi in Southern India to study its UHI. Twelve mobile surveys were carried out from January 2011 to March 2013 to quantify UHI intensity. Pre-dawn UHI there was more intense than early night UHI, and its intensity in winter was stronger than in summer. UHI observed during winter were 4.6°C and 3.7°C in pre- dawn and early night respectively. The study area was classified into ten different local climate zones based on the standard zone properties. Thermal gradient between different zones and cooling rates observed in these zones were computed, which validates the LCZ classification. Maximum intensity was seen in Compact Midrise zones which cover the central part of the city. Most intense cooling was observed in openset and sparsely built regions in all seasons. Standard zone properties alone were inadequate to explain variation of UHI intensity of same classes with different surface area and diverse adjacent zones. Two more zone properties, radial distance to adjacent zone called Zone Boundary Distance, and the Nearest Adjacent Zone, are proposed here to overcome this. The use of these additional parameters gives a better understanding of the intra zone variation of UHI intensity of the same classes with different coverage area and diverse adjacent zones.