The following article will analyze the formation of K Island, a territory situated east of Musura Golf, close to Sulina town in Danube Delta. The analysis utilizes different remote sensing techniques using images from Landsat and Sentinel satellites.

K Island is situated north of Sulina distributary and was formed via natural sedimentation process. The island was formed starting in 90's and it is Romania's newest territory. Historically, both K Island and Musura Golf are part of an international territorial dispute between Romania and Ukraine, starting with 1940 when the former USSR occupied part of the territory. According to a bilateral treaty from 1997, the island is shared between Ukraine (5km) and Romania (2km) but an unilateral declaration of Ukraine from 2010, place the island on Ukraine territory.

        The images surprising the formation of the island were collected using images provided by Landsat satellite family, operated by NASA. Technically, this satellite family are using an sun-synchronous orbit, at an altitude of about 700km. The orbital inclination is 98 degrees, meaning that the orbital period will be around 99 minutes revisit time is about 16 days. Image resolution is 30m and they were collected using geemap module.

        The formation of the island is visible in the right side of the time-lapses, having a North - South orientation, starting with 1995. The first time-lapse show the island formation using visible spectrum (RGB colors), while the second uses images from non-visible spectrum (SWIR - short wave infrared 2.11 - 2.29 µm wave length și NIR - near wave infrared 0.85 - 0.88 µm wave length). Also, the natural sedimentation process can be observed around Musura Golf, which represent Ukrainian argument for the territorial dispute.

            The next section is related to automatic detection of shores using computer vision techniques. For this purpose CoastSat module was utilized, using a neural network (multi-layer perceptron) for classifying three types of surfaces: sand, water and whitewater. For training the model both Landsat 8 and Sentinel 2 images were used. Sentinel 2 is operated by ESA and offers 10m image resolution, which should led to greater accuracy for detecting shores.

Automatic shore detection in 2015 using Sentinel 2 imagery  

Automatic shore detection in 2019 using Landsat 8 imagery  

        Technically the major differences between Sentinel 2 and Landsat 8 are related to image resolution (10m vs 30m), revisit period (5 days in constellation vs 16 days). Of course, there are also other major differences but they will be omitted for the scope of this research.

            Next plot will show island evolution during 2015 - 2021 period, each color representing shores at a given time. The expansion and bending properties are easily visible. 

1. Reach below link
2. Wait for map loading
3. Choose desired parameters (or use default values)
4. Click Submit button
5. Wait 2-3 minutes for image downloading and processing
6. Go on map to East part of Romania (Danube Delta, near Black Sea)