Characteristics and trend analysis of the relationship between land surface temperature and nighttime light intensity levels over China

Abstract

Nighttime light (NTL) imagery, as an excellent data source for monitoring urban development and human activity, has been used in research concerning land surface thermal environment. However, previous studies have only taken NTL data as a measure of urbanization degree or to obtain intermediate products for LST studies, such as urban impervious surface area and building density. Few studies have systematically analyzed the spatial and temporal variations of different light levels and surface temperatures. In this study, a LST–NTL rank correlation model was constructed based on MOD11C3 and DMSP/OLS data to analyze the characteristics and trends of the relationship between LST and NTL, during both daytime and nighttime over China in 2012. The findings revealed a strong positive correlation between NTL level and LST, with the peak correlation (R2 > 0.85) observed during July–September, which indicated that, with the increase of the light intensity, the LST has an overall upward trend. The trend was relatively more stable during nighttime (variation range of R2 was 0.3) than during daytime (variation range of R2 was 0.44). Moreover, it was greatly enhanced without considering NTL intensity saturation pixels in the NTL partition system, and was further improved after removing pixels from urban centers, which was particularly evident at nighttime. This provided evidence that NTL intensity can be a good indicator for the distribution of urban thermal environment, particularly outside the urban centers.