Major dust outbreak over the Taklimakan Desert seen in Meteosat-8 images in March 2019.
By Jochen Kerkmann (EUMETSAT)
Dust storms are very common in the Taklimakan (also spelled Taklamakan) Desert — the largest, warmest, and driest desert in China.
The Taklimakan Desert sits between the mountain ranges of the Tien Shan (or Tian Shan) in the north and the Kunlun Shan in the south. Far from any ocean, the desert experiences few, if any, effects of the rainy season of the Asian monsoon, that waters other parts of the continent. Because the basin lacks drainage, any water that enters it can only evaporate, leaving behind salt.
The Taklimakan Desert qualifies as China’s biggest, hottest, and driest desert. It also qualifies as one of the world’s largest shifting sand deserts, with dunes reaching a height of up to 200 meters, and it is one of the world's dust hot spots.
Figure 1 shows the weather situation over Western China on 22 March, as seen in the enhanced Meteosat-8 Natural Colour RGB (with reflectances displayed in the range 0 to 40%). A nearly opaque dust cloud not only fills the central and western parts of the Tarim Basin in which the Taklimakan Desert sits, but even pushes into the valleys of Kunlun Shan.
The dust cloud appears in pale beige to ochre in colour, obscuring the view of the underlying desert floor. High-level cirrus clouds (cyan) can be seen in the central and south-eastern part of the image, not to be confused with the snow-covered mountains that also appear as cyan in colour, but a darker cyan than the cirrus clouds.
Figure 2: Meteosat-8 Dust RGB, 19 March 02:00–18:00 UTC
To monitor the dust cloud during the day and at night, the IR-based Dust RGB can be used. The animation from 19 March, 02:00-18:00 UTC (Figure 2) shows the initial development of the dust outbreak. The dust cloud, or dust storm, started in the eastern part of the Tarim Basin and quickly moved westward. High level clouds partly obscured the dust cloud. The dark magenta colour and the sharp western border clearly classify the dust as being very thick, low-level dust, also known as a dust haboob.
Being trapped in the Tarim Basin by the Kunlun Shan and Tien Shan mountains, the dust cloud did not move, staying stationary for several days, see the Dust RGB images from 21 and 22 March (Figure 3). The only thing that changed was the colour of the dust cloud in the imagery, getting brighter day by day, a sign that the cloud got thinner.
Dust was still visible on 26 March (Figure 4), seven days after the dust cloud itself had lifted!