# The Application of Satellite Image Analysis in Oil Spill Detection
## 2 Materials and Methods  
### Study Site and Problem Description  
The river Ambarnaya near Norilsk is the area studied. It has a length of 60 km and a total area of 428 km\({}^{2}\). The river is supplied by rainwater and melting water [29]. It is shallow and the bottom is made up of gravel and glacier moraine limestone [30]. The river begins with its source, the Ambarnaya River (69\({}^{\circ}\)16\({}^{\prime}\)17\({}^{\prime\prime}\) N 87\({}^{\circ}\)45\({}^{\prime}\)21\({}^{\prime\prime}\) E), then flows northward into Lake Pysasino (69\({}^{\circ}\)28\({}^{\prime}\)44\({}^{\prime\prime}\) N 8\({}^{\circ}\)55\({}^{\prime}\)27\({}^{\prime\prime}\) E) (Figure 1). As a result of an accident, about 20,000 tons of diesel fuel flowed into the Ambarnaya River on 29 May 2020. The river is polluted in an area of approximately 7 km, or 20% of its total length. Dams have been installed in the river to prevent further pollution, but they have not completely prevented the spill of oil products into Lake Pysasino. Freshwater lakes cover an area of 735 km\({}^{2}\).  
The Norilsk region is rich in natural resources, such as nickel, copper, platinum, or high value hard coal [31]. According to 2004 data [21], the region's mineral resources have reached nearly 480 billion tonnes. The city is mainly known as Nornickel, the company that manufactures heavy metals. It produces approximately 500,000 tonnes of copper annually, 500,000 tonnes of nickel annually, and 2 million tonnes of sulphur dioxide annually [32].  
Figure 1: The study location.  
This is more than the annual production of France as a whole [23]. The National Aeronautics and Space Administration reports that heavy metal contamination in the areas near the Norilsk complex is so large and extensive that it has become economically viable to extract contaminated soil containing the elements platinum and palladium [23]. The list includes air pollution caused by solid particles, radioactive isotopes of strontium 90 and caesium 137. These are characterized by a long half-life. In the summer, the temperature difference in the atmosphere prevents smoke from escaping, leading to smoke accumulating as smog. The location of the factory makes the situation even worse, because it is adjacent to the river, which means that regardless of the direction, the wind blows smoke in the city. A 1999 study showed that copper and nickel concentrations in the soil increased up to 60 km from the city [33]. Most of the surrounding areas of Norilsk are Tundra, Lasundra, and the deciduous forest of the boreal, Taiga. The vegetation period is from June to August. Subarctic climates are characterized mainly by small vegetation such as marshes, lichens, and dwarf trees. There are also pines, junipers, and hemisphere plants [23]. In a 2003 study, it was found that the trees with the highest concentrations of sulphur in the needles are found in the most damaged areas of the forest [34].  
The disaster was described as the second-largest oil spill in Russian history. On 29 May 2020, a support under the fuel tank of the Norilsk power plant of the Nadezhda metal factory collapsed, ejecting about 21,000 tonnes into the surrounding river. The oil contaminated the Ambarmaya River and surrounding areas, and then entered Lake Piasino, which flows into the Arctic Kara Sea. Total oil pollution has contaminated 350 square kilometres of land. The 1989 Exvon Valdez disaster was similar, when oil tankers descended in Prince William Bay, Alaska, spilling 37,000 tons of oil into the surrounding waters. [PERSON], chief executive of Rosprirodnadzor (the Federal Russian Natural Resource Surveillance Service), said that water samples tested exceed the permitted concentrations of oil products by thousands [35]. Norilsk-Taimyr Energy Company stated that the incident was caused by global climate change and global permafrost defrost, in particular the 2020 heat wave.