Aligning Pixel Values of DMSP and VIIRS Nighttime Light Images to Evaluate Urban Dynamics

Kang Wu,Xiaonan Wang

doi:10.3390/rs11121463

Abstract

The brightness of pixels in nighttime light images (NTL) has been regarded as the proxy of the urban dynamics. However, the great difference between the pixel values of NTL from the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS) and the Suomi National Polar-orbiting Partnership satellite’s Visible Infrared Imaging Radiometer Suite (Suomi NPP/VIIRS) poses obstacles to analyze economic and social development with NTL in a continuous temporal sequence. This research proposes a methodology to align the pixel values of both NTL by calibrating annual DMSP images between the years 1992–2013 with a robust regression algorithm with a quadratic polynomial regression model and simulating annual DMSP images with VIIRS images between years 2012 and 2018 with a model consisting of a power function and a Gaussian low pass filter. As a result, DMSP annual images between years 1992–2018 can be produced. Case study of Beijing and Yiwu are conducted and evaluated with local gross domestic product (GDP). Compared with the values of DMSP and VIIRS annual composites, the Pearson correlation coefficients of DMSP and simulated DMSP annual composites in 2012 and in 2013 increase significantly, while the root mean square error (RMSE) decrease evidently. In addition, the correlation of the sum of light of NTL and local GDP is enhanced with a simulation process. These results demonstrate the feasibility of the proposed method in narrowing the gap between DMSP and VIIRS NTL in pixel values.

Highlights

Understanding the dynamics of urban expansion is very essential for better tackling the ongoing urban system changes and sustainability around the different scales [1]
The use of nighttime light images (NTL) in multitemporal socioeconomic research attributes to the correlation between the sum of light (SOL) and socioeconomic variables, and it is of great advantage to combine NTL from DMSP and VIIRS in urban studies to keep the continuity of temporal sequence
A quadratic polynomial regression model instead of a linear one was used to calibrate DMSP NTL in 1992–2013, and a stepwise sensitive analysis was applied to determine the optimal values of parameters in the power function and Gaussian low pass filter

Summary

Introduction

Understanding the dynamics of urban expansion is very essential for better tackling the ongoing urban system changes and sustainability around the different scales [1]. The Defense Meteorological Satellite Program’s Operational Linescan System Visible Near-Infrared Band (DMSP/OLS VNIB) and the Suomi National Polar-orbiting Partnership satellite’s Visible Infrared Imaging Radiometer Suite (Suomi NPP/VIIRS) Day/Night Band are two main sources of NTL. The former, referred to as DMSP in the following parts, provides NTL from the year 1992 to year 2013, while the latter, referred to as VIIRS, produces NTL from the year 2012 to the present. On the other hand, DMSP and VIIRS NTL are different in various aspects, which hinders the combined use of both NTL

Methods

Results

Discussion

Conclusion