VZA-COLD detects artificial light at night (ALAN) change at 15 arc-second spatial resolution with daily updating capability based on NASA's Black Marble products.
This page has been created for peer review purposes.
We provide the code resources (package name associated with the folder provided in the code) for our publication, which are programmed in MATLAB (2022b) and Python (3.10):
- VZACOLD: Nighttime light change detection package (MATLAB)
- Analysis: Code for data analysis and visualization (MATLAB + Python)
Our global NTL change product provides artificial light at night change information, including change time (Day-of-year and Year) and change intensity for abrupt change and gradual change, for each year at the VIIRS 15-arc-second pixel level.
Visualization of the dataset can be found through Google Earth Engine-based application.
Collection 1 (beta version) of the global ALAN change product dataset (2014–2022), described in Li et al. (2026), can be downloaded from [TBD].
The products are provided in the Suomi-NPP VIIRS 15-arc-second linear latitude/longitude grids (or geographic) (see Figure 2 in this document). Annual change maps are delivered in GeoTIFF format, including:
-
Abrupt change time in Day-of-Year
Filename: AbruptChangeTime_YYYY.tif (where YYYY means year)
Pixel Value: Day-of-year of the detected abrupt ALAN change events -
Abrupt change intensity:
Filename: AbruptChangeIntensity_YYYY.tif (where YYYY means year)
Pixel value: Intensity of the abrupt ALAN change in units nW·cm⁻²·sr⁻¹ -
Gradual change intensity:
Filename: GradualChangeIntensity_YYYY.tif (where YYYY means year)
Pixel value: Intensity of the gradual ALAN change in units nW·cm⁻²·sr⁻¹
For user discussions or comments, please feel free to contact us by email or visit [the project’s issue page] (https://github.com/GERSL/VZA-COLD/issues)
Tian Li (tianli@uconn.edu) and Zhe Zhu (zhe@uconn.edu) at the Department of Natural Resources and the Environment, University of Connecticut.
Li, T., Zhu, Z., Wang, Z., Kyba, C. C. M., Seto, K. C., Yang, Y., Qiu, S., Kuester, T., Fragkias, M., Chen, X., Meyer, T. H., Rittenhouse, C. D., Tai, X., Cullerton, M., Hong, F., Grinstead, A., Song, K., Suh, J. W., Yang, X., Kalb, V. L., Deng, C., & Román, M. O. Increasing volatility in human nighttime activity revealed by daily and high-resolution satellite imagery.
Li, T., Zhu, Z., Wang, Z., Román, M. O., Kalb, V. L., & Zhao, Y. (2022). Continuous monitoring of nighttime light changes based on daily NASA's Black Marble product suite. Remote Sensing of Environment, 282, 113269.