Continuous monitoring of nighttime light changes based on daily NASA's
Black Marble product suite
Abstract
Monitoring nighttime light (NTL) change enables us to quantitatively
analyze the dynamic patterns of human activity and socioeconomic
features. NASA’s Visible Infrared Imaging Radiometer Suite (VIIRS)
Day/Night Band (DNB) atmospheric- and Lunar-BRDF-corrected Black Marble
product (VNP46A2) provides daily global nighttime radiances with high
temporal consistency. However, timely and continuous monitoring of NTL
changes based on the dense daily DNB time series is still lacking. In
this study, we proposed a novel Viewing Zenith Angle (VZA) stratified
COntinuous monitoring of Land Disturbance (COLD) algorithm (VZA-COLD) to
detect NTL change at 15 arc-second spatial resolution with daily
updating capability based on NASA’s Black Marble products. Specifically,
we divided the clear observations into four VZA intervals (0–20°,
20°–40°, 40°–60°, and 0–60°) to mitigate the temporal variation of
the NTL data caused by the combined angular effects of viewing geometry
and the complex surface conditions (e.g., building heights, vegetation
canopy covers, etc.). Single-term harmonic models were continuously
estimated for new observations from each VZA interval, and by comparing
the model predictions with the actual DNB observations, a unified set of
NTL changes can be captured continuously among the different VZA
intervals. The final NTL change maps were generated after excluding the
consistent dark pixels. Results showed that the VZA-COLD algorithm
reduced the DNB data temporal variations caused by disparities among
different viewing angles and surface conditions, and successfully
detected NTL changes for six globally distributed test sites with an
overall accuracy of 99.71%, a user’s accuracy of 87.18%, and a
producer’s accuracy of 68.88% for the NTL change category.