5865 x 3915 px | 49,7 x 33,1 cm | 19,6 x 13,1 inches | 300dpi
Data acquisizione:
17 marzo 2019
Ubicazione:
Olkhon Island on Lake Baikal, Russia
Altre informazioni:
Lake Baikal is a rift lake located in southern Siberia, Russia, between Irkutsk Oblast to the northwest and the Buryat Republic to the southeast. Lake Baikal is the largest freshwater lake by volume in the world, containing 22–23% of the world's fresh surface water. With 23, 615.39 km3 (5, 670 cu mi) of fresh water, it contains more water than the North American Great Lakes combined. With a maximum depth of 1, 642 m (5, 387 ft), Baikal is the world's deepest lake. It is considered among the world's clearest lakes and is considered the world's oldest lake, at 25–30 million years. It is the seventh-largest lake in the world by surface area. Like Lake Tanganyika, Lake Baikal was formed as an ancient rift valley and has the typical long, crescent shape, with a surface area of 31, 722 km2 (12, 248 sq mi). Baikal is one of the clearest lakes in the world. During the winter, the water transparency in open sections can be as much as 30–40 m (100–130 ft), but during the summer it is typically 5–8 m (15–25 ft). Baikal is rich in oxygen, even in deep sections. In Lake Baikal, the water temperature varies significantly depending on location, depth, and time of the year. During the winter and spring, the surface freezes for about 4–5 months; from early January to early May–June (latest in the north), the lake surface is covered in ice. On average, the ice reaches a thickness of 0.5 to 1.4 m (1.6–4.6 ft), but in some places with hummocks, it can be more than 2 m (6.6 ft). During this period, the temperature slowly increases with depth in the lake, being coldest near the ice-covered surface at around freezing, and reaching about 3.5–3.8 °C (38.3–38.8 °F) at a depth of 200–250 m (660–820 ft). After the surface ice breaks up, the surface water is slowly warmed up by the sun, and in May–June, the upper 300 m (980 ft) or so becomes homothermic (same temperature throughout) at around 4 °C (39 °F) because of water mixing.
