Embedded Files
Methods
Methods
Our data, which we sourced from NASA's Earthdata, was from the VIIRS sensor on the Suomi NPP satellite. The specific product that we used was the Gap-Filled, Lunar-Adjusted, night-time imagery. We processed the raw rasters in ENVI, and used ArcGIS Pro to make more complex maps.
Our study area covered the entirety of south-east Ukraine, from Kharkiv to Crimea, with data taken at a frequency of once a month, ranging from pre-war 2022 to present-day 2024.
We used ENVI to subtract time series, giving us difference images that could determine which areas were being attacked.
Our hypotheses: areas which go dark could be getting attacked, and areas which remain bright indicate areas which are not under active fighting (whether under Russian or Ukrainian control)
Results
Results
We illustrate the change in nighttime illumination as depicted by VIIRS data collected from 2022 to 2024. We perform the analysis by comparing illumination values from a pre-war image, specifically, a base image from January 2nd, 2022. Comparing relative illumination through raster subtraction can show patterns more clearly. Areas which become dark are shown in blue, which areas which become brighter are shown as bright yellow.
From our data, we can see that areas belonging to metropolitan areas in southeastern Ukraine immediately go dark, though it’s difficult to see a clear pattern of migration from night-time images alone.
Areas which are under well-established Russian occupation, such as Crimea, become brighter after the base date, which may be indicative of lower risk of attack.
Interactive map depicting the difference in night-time illumination between January 2nd, 2022 and February 14th, 2024.
Predictability - Kherson
Predictability - Kherson
By inspecting changes in the city of Kherson as it’s passed from side to side, we observe that significant changes are precipitated by a change in light intensity. This encompasses both active fighting as well as a static front line with constant shelling. The observed pattern of areas darkening before attack is consistent with other works, including Xu, Barbot, & Wang (2024).
September 1, 2022
Ukraine begins campaign to retake the Russian-controlled city
November 1, 2022
Ukraine successfully liberates Kherson; night lights dim amidst the fighting
February 1, 2023
Kherson darkens as Russian shelling intensifies
June 1, 2023
Kherson is fully dark; one week later, Russia detonates Kakhovka Dam and floods city
Tactics
Tactics
This animation illustrates the stark difference in night illumination between the two sides of the front line. Since the beginning of the invasion, Ukrainian cities immediately become dark and stay dark, while Russian cities, even in the occupied territories close to the front, remain unflinchingly bright.
Discussion
Discussion
If lights go out, trouble is about
If lights go out, trouble is about
The sudden disappearance of night illumination can signal either that an area is under attack, or that operations will take place there soon. Enemies can also take actions informed by these changes, making them a strong predictor of moves and countermoves (Kakissis, Lytvynova, & Harbage 2023).
War is not equal
War is not equal
Russian forces are more than willing to bomb and shell indiscriminately, while Ukraine tries to minimize destruction and limit casualties to military targets. Ukrainian cities go dark both to hide from drone attacks, and because drones and bombs take out power stations themselves (Xu, Barbot, & Wang 2024).
Cumulative change in night illumination
Feb. 2022 - Feb 2024
Click and drag the blue slider to compare Landsat and VIIRS images of Dnipro, Ukraine.
Future Research
Future Research
With VIIRS's low spatial resolution (>370m), it can be difficult to accurately see and analyze minute changes. Higher spatial resolution, as is available on different sensors, would give more specific information and therefore higher quality analysis.
While Very High Resolution (VHR) imagery is available, it is prohibitively expensive and publicly-funded solutions are not yet available (Bennett et al. 2022).
References
References
Kakissis, J., Lytvynova, P., Harbage, C., 2023, Ukraine's troops long planned their move on Russian forces. Then came the flood. Available online at: https://www.npr.org/2023/06/22/1183167902/ukraine-flood-offensive-russia-war (accessed 13 March 2024).
Xu, H., Barbot, S., Wang, T., 2024, Remote sensing through the fog of war: Infrastructure damage and environmental change during the Russian-Ukrainian conflict revealed by open-access data. Natural Hazards Research, 6.
Bennet et al., 2022, Improving Satellite Monitoring of Armed Conflicts. Earth's Future, 10, 9.
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