Windblown dust in the Tarim basin, Northwest China.

Tarim Basin in western China is home to the world's second-largest mobile dune desert, Taklimakan Desert, and it's one of Asia's primary sources of sand and dust storm. Observations of windblown dust are insufficient over this hyper-dry inland region. Here we present a comprehensive study based on consecutive in-situ field observations, meteorological records, environmental monitoring data and satellite measurements over the Tarim Basin for a full year in 2015. The results show that during the severe sand and dust storm events, the observed ambient PM10 (particulate matter with an aerodynamic diameter ≤ 10 μm) concentration rises rapidly, with a maximum value exceeding 10,000 µg/m3 per hour, while wind speeds reach 10-30 m/s and visibility is reduced to less than 10 m. Soil particulates can be blown vertically into the atmosphere at a height of 3-12 km. High volumes of dust deposition were measured at environmental monitoring stations, ranging from 1764 to 3800 g/m2 yr. Those significant flux levels of ambient particulate matter (PM) concentrations and dust depositions are strongly associated with frequent dust occurrence in the arid environment of the Tarim Basin. Satellite measurements of aerosol optical depths (AOD) show a broad spatial pattern of dust aerosols distribution over the basin, with dense dust remaining suspended for long periods of time (3-5 months in spring and summer seasons). The wind regimes, basin-like topography, thermodynamic condition, and loose sandy surfaces greatly affect the regional aeolian dust environment in the Tarim Basin, which lead to a significantly high dust emission, ambient PM concentration and dust deposition.