[M-IS09] dust

[MIS09-08] Occurrence of micro-meso scale dust storms and its relationship to the vegetation and topography in Mongolian grassland and Gobi Desert

*Kenji Kai¹, Kei Kawai², Teruya Maki³, Jun Noda⁴ (1.College of Education, Ibaraki University , 2.Nagoya University, 3.Kanazawa University, 4.Rakuno-Gakuen University)

Keywords:Asian dust, Himawari-8 Dust RGB, Hotspot of dust storms

Gobi Desert and Mongolian grassland are one of the main sources of the Asian dust. In order to investigate the occurrence of micro-meso scale dust storms and its relationship to the vegetation and topography, we conducted moving observations running across the Gobi Desert from Ulaanbaatar to Dalanzadgad in springs of 2015-2017. An optical particle counter (OPC: Aerotrak 9306-V2), a sunphotometer (Microtops II) and meteorological instrument were installed in a car.



The vegetation had a suppression effect on the dust emission. Number concentrations of coarse particles (1-10μm) decreased from the desert to the grassland. They had significant negative correlations with the vegetation (NDVI) from 3μm to 10μm, but the number concentration at 0.3 – 0.5 μm had little correlation to the vegetation.



During the moving observations, we found a hotspot of dust storms in the Gobi Desert. An analysis of Himawari-8 Dust RGB clearly shows that the hotspot appeared at a jointing point of two valleys, a bottleneck and an exit of a valley.



In summary, the horizontal distribution of number concentrations of aerosol particles reflected the surface vegetation. Locations of the hotspot were determined by a local topography such a jointing point of two valleys.