Potentiality of SDGSAT-1 glimmer imagery to investigate the spatial variability in nighttime lights

Abstract

The successful launch of Sustainable Development Science Satellite 1 (SDGSAT-1) complements the existing nighttime lights (NTL) data with high spatial resolution in the three visible bands (40 m) and the panchromatic band (10 m). This study aimed to evaluate the potentiality of the new NTL imagery – SDGSAT-1 – in revealing the spatial variation in NTL intensity. We compared the NTL image from SDGSAT-1 with other existing NTL datasets: the Visible infrared Imaging Radiometer Suite-Day Night Band (VIIRS-DNB), Luojia1-1 (LJ1-01), and photographs from the International Space Station (ISS-P) at spatial resolutions of 500 m, 130 m, and 10 m, respectively. Then, we investigated the intraurban NTL spatial variability of eleven urban land-use types with analysis of variance (ANOVA). In addition, we used random forest (RF) regression to analyze the relationship between explanatory factors and NTL variation. The results showed the following: (1) The quality of the SDGSAT-1 NTL image was comparable with ISS-P and better than VIIRS-DNB and LJ1-01 imagery in spectral and spatial resolution. (2) The ability of the RGB bands and grayscale brightness of the SDGSAT-1 NTL image to distinguish various land use types outperformed that of the ISS-P, LJ1-01, and VIIRS-DNB images. (3) The NTL spectral index SONDI, combined with three visible bands, could improve the ability of a single band to show the lighting differences in intraurban areas. (4) The nine variables explained 39.20%–42.30% of the NTL intensity variability in the four RF models. Road density and public POI density were the most important variables in the red-green and blue bands, indicating that high-pressure sodium and lighting-emitting diode lamps were primarily deployed in the road and public areas, respectively. Meanwhile, the potential applications of SDGSAT-1 NTL imagery were further discussed. Our findings indicate the great potential of SDGSAT-1 NTL imagery for supporting sustainable urban development.