夜光遥感视角下的巴基斯坦区域发展差异分析

Analysis on Disparity of Regional Development in Pakistan Under Perspective of Nighttime Light Remote Sensing

  • 摘要: 获得巴基斯坦的区域发展规律对于支持中巴经济走廊建设具有参考意义。基于可见光红外成像辐射仪(visible infrared imaging radiometer suite,VIIRS)月度夜光遥感影像,分别使用夜光变化率、Mann-Kendall(MK)趋势检验法和位序-规模法则3种方法研究巴基斯坦省级/城市级、格网级以及东西地带3个地理尺度下的夜光变化规律。分析显示,2012—2019年巴基斯坦的夜光增长率为47.96%,各省级区域均有不同程度的发展,其夜光增长率均大于15%;根据MK趋势检验,在5 km格网尺度下,旁遮普省拥有夜光上升趋势格网最多(1 905个),信德省拥有夜光总量下降趋势格网最多(338个);根据城市夜光的位序-规模分析,东部地带和西部地带的帕累托指数都在逐步缩小,说明巴基斯坦城市结构层次间的差距正在逐渐缩小,整个地区的城市规模发展日趋平衡。此外,缺乏稳定的电力供应可能是部分地区夜光亮度偏低的原因。在长时间序列、多空间尺度下揭示巴基斯坦的区域发展规律,可以为中巴经济走廊的规划提供一定的科学依据。

     

    Abstract:
      Objectives  It is important to know the pattern of Pakistan's regional development for the construction of China-Pakistan Economic Corridor.
      Methods  We used visible infrared imager radiometer suite(VIIRS) nighttime light remote sensing image as the main data source, and implemented Savitzky-Golay(SG) filtering algorithm to repair the missing values of the images. Night time light change ratio (NLCR), Mann-Kendall(MK) trend test method and rank-size rule were carried out to study the nighttime light change patterns of province level, city level, geographic grid level, and east-west zone in Pakistan.
      Results  The analysis result of NLCR shows that from 2012 to 2019, NLCR of the entire Pakistan is 47.96% and all provincal regions has developed to a certain degree with NLCR larger than 15%. NLCR of Gwadar Port is 126.94%, which is the highest in 15 node cities on east and west lines of China-Pakistan Economic Corridor. Additionally, the development of 15 node cities on east and west lines of China-Pakistan Economic Corridor was unbalanced. The results of MK trend test show that at the geographic grid scale of 5 km, there are 1 905 grids with the total nighttime light upward trend in Punjab and 338 grids with the total nighttime light downward trend in Sindh. It is found that most grids with the total nighttime light downward trend are located in rural areas of Sindh, which is consistent to the fact that there is a serious power shortage problem in rural areas of Sindh. The analysis results of rank-size rule show that the Pareto indexes of both eastern and western zones are gradually decreased, indicating that the distribution of urban size in Pakistan becomes more balanced. And the lack of stable power supply may be the reasons for the low brightness of nighttime light in some areas.
      Conclusions  The regional development patterns of Pakistan under long-term time series and multiple spatial scales can provide a certain scientific basis for the planning of China-Pakistan Economic Corridor.

     

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