Analysis Of Influencing Factors Of Nighttime Light Intensity And Its Application In Urban Growth

Nighttime light data is widely used in various social,economic,and urban studies.Factor analysis of night light intensity helps understand the mechanism of nighttime light in depth,and provides good support for the application research of nighttime light.This paper selects 281 cities in mainland China as the research object,using the VIIRS nighttime light data,with the help of hierarchical linear model,to study the impact of different factors on the city nighttime light intensity from the provincial level and city level and the effect which the interaction of factors of different levels causes on the light intensity.Based on that,using DMSP / OLS nighttime light time series data,the city's growth pattern was studied from the perspective of internal intensity and external expansion for 45 cities in mainland China.The main content of this paper are as follows:(1)Data acquisition and preprocessing.For the VIIRS and DMSP/OLS nighttime light remote sensing data required for the experiment,this paper specifically studied two different data preprocessing methods and processes.The purpose of the former is to eliminate various data noises to improve the overall accuracy of the data,and the latter one is to enhance the coherence and consistency of data.In addition,this paper also introduces the sources of population data,NDVI data,elevation data and other social-economic statistics.(2)Factor analysis of night light in cities.At this stage,after introducing the theory and advantages of the hierarchical linear model,this paper selects 12 and 16 social,economic,and natural elements at the city level and the provincial level respectively and analyzes the univariate correlation between the 12 elements at the city level and the average nighttime light intensity of cities.Then,principal component analysis was conducted to extract 6 and 4 principal component factors at the city level and the provincial level respectively,to establish a hierarchical nested data set,and complete the construction of a hierarchical linear model.Finally,the effects of different factors on city light and the effect which the interaction of factors of different levels causes on the light are analyzed from the fixed and random effects of the model.(3)Research on urban growth patterns based on night light data.In this part,this paper first explains the connection between urban growth and nighttime light,indicating that night light can be used as an ideal carrier for urban growth.Then,based on the DMSP/OLS night light time series data,the paper separately extracts the intensity level and expansion level of the city,and conducts time evolution analysis,spatial visualization,autocorrelation analysis and clustering analysis from the perspective of intensity growth and expansion growth of the city.Finally,the correlation between urban intensity growth and expansion growth was studied.This paper conducts the factor analysis of nighttime light based on the hierarchical linear model,which reveals the mechanism of the light and also provides strong support for the application research of the night light in the urban growth patterns.Furthermore,from the perspective of the city's intensity growth and expansion growth,the city's growth patterns and laws are revealed,and results of the analysis can be used to provide better planning and decision-making in the sustainable development of the city.