高原地区城市不透水面与地表温度时空分布研究

An Analysis of the Spatiotemporal Distribution of Impervious Surface and Land Surface Temperature in Plateau Areas

  • 摘要: 拉萨市作为高原地区的重要城市之一,其城市不透水面的变化及由此而产生的地表温度变化对脆弱地区的生态影响非常显著,因此,选取该市城区及周边郊区作为实验区,利用线性光谱解混和大气校正算法获得该地区2009—2018年城市不透水面盖度(Impervious Surface Coverage, ISC)和地表温度数据,同时结合温度贡献指数(Contribution Index, CI)讨论了高原地区城市不透水面与地表温度时空分布的关系,拟为长期监控高原地区的基础生态变化提供帮助.研究结果表明:(1)由于季节因素的影响,城市热环境对ISC的响应存在2种不同的模式:①冬季,ISC < 0.1的区域对城市热环境的贡献为正;ISC≥0.1的区域的贡献为负. ②夏季,ISC < 0.1的区域对城市热环境的贡献为负;ISC≥0.1的区域的贡献为正. (2)冬季,CI与ISC呈现负相关关系.夏季,当ISC < 0.5时,CI呈现下降的趋势;当ISC≥0.5时,CI呈现上升的趋势. (3)冬季,地表温度随着ISC的增加而缓慢下降;夏季,ISC对地表温度的影响表现为“V”形状.

     

    Abstract: As an important city in the plateau areas, Lhasa has a significant impact on the vulnerable area due to the change in the impervious surface and the temperature variation resulting from the change. Therefore, Lhasa, including the urban area and the suburbs, was selected as an experimental area. Impervious surface coverage (ISC) and land surface temperature in the experimental area were estimated respectively with the linear spectral mixture analysis and atmospheric correction. Contribution index (CI) to the urban thermal environment, combined with the ISC and land surface temperature data over the past decade (2009-2018) were used to discuss the relationship between ISC and land surface temperature in terms of spatiotemporal distribution with the purpose of providing help for long-term monitoring of basic ecological change in plateau areas. The results show that, due to seasonal variations, the response of land surface temperature to ISC has two patterns. The areas with ISC ranging from 0 to 0.1 have positive contributions to the urban thermal environment while the areas with ISC greater than or equal to 0.1 have negative contributions in winter. The areas with ISC ranging from 0 to 0.1 have negative contributions to the urban thermal environment while the areas with ISC greater than or equal to 0.1 have positive contributions in summer. In winter, the relationship between ISC and CI shows a negative correlation. In summer, CI shows a declining trend at ISC < 0.5 and a rising trend at ISC≥0.5. With the increase of ISC, land surface temperature decreases slightly in winter. The influence of ISC on land surface temperature shows a V-shape tendency in summer.

     

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