Journal of Geo-information Science >
The Hot Spot and Spatiotemporal Changes of the Land Surface Temperature in Fuzhou
Received date: 2018-11-20
Request revised date: 2019-02-21
Online published: 2019-05-25
Supported by
Public Welfare Research Institutes of Fujian Province, No. 2019R1102
Natural Science Foundation of Fujian Province, No. 2018J01739.
Copyright
As the largest developing country in the world, China has witnessed rapid urbanization in the recent years. A large amount of natural land surface has been transformed into artificial land surface, leading to a series of environmental problems, among which the most prominent is urban heat island.Therefore, how to mitigate the urban heat island effect caused by the acceleration of urbanization process has become a hot research direction. To accurately analyze the influence of urban spatial pattern on thermal concentration, this article used two periods of remote sensing imagery, Landsat ETM+ on May 4, 2000 and Landsat OLI on July 27, 2016, to obtain the land cover information of Fuzhou and verified the accuracy. The hot spot analysis of the retrieved land surface temperature (LST) and impervious surface area (ISA) of Fuzhou were used to study the change characteristics, spatial concentration characteristics, and scale effect of LST in the past sixteen years of urbanization. The hot spot results show the following two findings. (1) The spatial thermal concentration could be better illustrated through analyzing the relationship between the distance from city center and LST. In 2000, the urban heat island effect was significant within a 1.03 km distance from the city center; however, in 2016 the distance increased to 2.1 km and the number of hot spots increased from three to five. During this period, the hot concentrated area (the hot and less hot areas) also increased from 15.7% to 47.3%. (2) Compared with other spatial autocorrelation analysis methods, Getis-Ord Gi* can help more directly analyze the impact of land cover change on LST and understand the details of the change of urban internal thermal intensity, because the formation of hot and cold spots depends on not only the level of LST. The hot spot method adopted in this study can be used for urban environmental protection and planning, and can also be used as a basis for urban land planning and thermal environmental impact analysis in the future. Meanwhile, the hot spot chart can be used to simulate urban microclimate and estimate the cooling effect of urban green space. In addition, comparative analyses of more multi-temporal and different cities can be further discussed in the future, especially studies on different types of cities, such as strip cities, polycentric cities and central cities.
CHEN Bingqian , ZHANG Youshui , CHEN Jingyuan , ZHAO Xue . The Hot Spot and Spatiotemporal Changes of the Land Surface Temperature in Fuzhou[J]. Journal of Geo-information Science, 2019 , 21(5) : 710 -719 . DOI: 10.12082/dqxxkx.2019.180597
Fig. 1 Landsat 8 imagery of Fuzhou City, acquired in July 2016图1 福州市2016年7月Landsat8遥感影像 |
Fig. 2 Normalized land surface temperature in Fuzhou City in 2000 and 2016图2 2000年和2016年福州市归一化地表温度 |
Tab. 1 Accuracy verification of the land cover classification in Fuzhou city in 2000 and 2016表1 2000年和2016年福州市土地覆盖分类精度验证 |
测试区 | 年份 | ETM+/OLI影像面积/km2 | Google影像面积/km2 | 平均差异/% ([ETM+/OLI-google]/google) | |||||
---|---|---|---|---|---|---|---|---|---|
ISA | 植被 | ISA | 植被 | ISA | 植被 | ||||
测试区1 | 2000 | 0.074 | 0.034 | 0.076 | 0.033 | -2.6 | 3.0 | ||
2016 | 0.082 | 0.014 | 0.079 | 0.013 | 3.8 | 7.2 | |||
测试区2 | 2000 | 0.406 | 0.020 | 0.377 | 0.021 | 7.7 | -4.8 | ||
2016 | 0.113 | 0.077 | 0.110 | 0.074 | 2.7 | 3.9 | |||
测试区3 | 2000 | 0.106 | 0.089 | 0.110 | 0.091 | -3.6 | -2.2 | ||
2016 | 0.387 | 0.046 | 0.356 | 0.048 | 8.7 | -4.2 | |||
测试区4 | 2000 | 0.207 | 0.122 | 0.215 | 0.129 | -3.7 | -5.4 | ||
2016 | 0.224 | 0.093 | 0.239 | 0.098 | -6.3 | -5.1 | |||
总计 | 2000 | 0.793 | 0.265 | 0.778 | 0.274 | 1.9 | -3.3 | ||
2016 | 0.806 | 0.230 | 0.784 | 0.233 | 2.8 | -1.3 |
Fig. 3 Impervious surface coverage (ISC) in the study area in 2000 and 2016, and areas with ISC changed over 95%图3 2000和2016年福州市内ISC>95%的变化情况 |
Fig. 4 Urban hotspot distribution in Fuzhou city in 2000 and 2016图4 2000年和2016年福州市热点分布 |
Fig. 5 Changes in the mean normal differential vegetation index (NDVI), mean normalized land surface temperature (MNLST), and mean ISC in Fuzhou City in 2000 and 2016图5 2000年和2016年福州市平均NDVI、MNLST和平均ISC变化情况 |
Fig. 6 Urban hotspot distribution in Fuzhou city in 2000 and 2016图6 2000年和2016年福州市热点分布 |
Fig. 7 Changes in the mean normalized land surface temperature (MNLST) and mean ISC at different distances from the hot spot center in 2000 and 2016图7 2000年和2016年距热点中心不同距离时MNLST和平均ISC变化情况 |
The authors have declared that no competing interests exist.
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