Ground Referencing Night Time Light Imagery—How Critical Is It to Conduct the Measurements at the Same Time the Image Is Acquired?

With the increasing availability of high-resolution (<50 m) spaceborne night time light imagery, it is now becoming more feasible to examine the correspondence between spaceborne and ground-based measurements of night lights. However, so far there have been very few studies that have conducted a ground-based campaign of night time brightness measurements during the overpass of a night light-sensitive satellite. Here we tested whether the correspondence between measurements is higher when ground-based measurements are conducted at the same time as the satellite overpass. We conducted measurements using a LANcube photometer along the same route on two consecutive nights (27–28 August 2025) in Brisbane, Australia, and compared them with an SDGSAT-1 (10–40 m) and Haishao-1 (10 m) images acquired concurrently in the evening and with an early morning ISS photo (8 m) acquired three months earlier. We found the correlation between ground-based and spaceborne measurements was not higher for simultaneous measurements, and the explanatory power of our model predicting night time brightness as measured from space increased when including horizontal and upwards ground-based brightness measurements alongside variables of canopy height, land use and road hierarchy. We confirmed the importance of multidirectional ground measurements and urban structure for understanding night time brightness levels measured from space.