Lake Alakol in eastern Kazakhstan is featured in this radar image captured by Copernicus Sentinel-1.
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Although radar images are naturally black and white, the colours in this false-colour composite result from the combination of three separate radar images, acquired a month apart in 2025. Each image has been given a different colour: blue for March, green for April and red for May. When the images are overlaid, the resulting colours highlight changes on the ground between the acquisitions. Areas that appear grey or white depict little or no change.
Alakol means ‘multicoloured lake’ and in this image it can be seen in the top left corner in varying shades of blue and green depending on variations in the frozen surface during the acquisition period. As this saltwater lake usually freezes for about two months at the end of winter, and breaks up in early spring, it appears mainly blue because, during the March acquisition, the surface was mostly frozen.
There are two smaller, shallower lakes to the northwest of Alakol. The closest is Koshkarkol, and part of Sasykkol, a freshwater lake, is also seen in the image. The variety of yellow, pink and magenta colours in the land surrounding the lakes denotes variations in vegetation between March and May.
The Alakol–Sasykkol lake system is both a Ramsar Wetland of International Importance and a UNESCO Biosphere Reserve. It is an important migratory stop and nesting area for a variety of water birds, including the Dalmatian Pelican and Greater Flamingo.
To the west of Alakol, we can see colourful agricultural structures in an alluvial fan. The triangular shape is formed when water runoff from the Dzungarian Alatau mountains, visible below, reaches the plain and spreads out, leaving behind fertile soil.
Lake Alakol is near the border with China’s Xinjiang Uygur Autonomous Region, in an area shaped by the Dzhungarian Gate. This natural valley forms a mountain pass through the Dzungarian Alatau range and connects central Asia to China.
The colourful feature visible south of Alakol is Aibi Lake, or Ebi Lake, the largest saltwater lake in northwest Xinjiang. It has shrunk dramatically over the years and the vibrant colours in the northern part of the basin show where the soil has been exposed during the acquisition period.
West of the lake, the Bortala Valley is scattered with a patchwork of farms and settlements along the course of the Bortala River. The colours highlight the various crop types and stages of growth, while built-up areas appear bright grey and white.