| Popis: |
In this paper, a severe dust storm which occurred in northern China is presented and its associated physics investigated. The main sand source regions of this storm were from the Badanjilin Desert in western Inner Mongolia (IM), western Hunshandakend sand lands and the Gobi Desert in southern Mongolia. This dust storm process was a typical cyclonic dust storm, induced mainly by intensive development of a Mongolian cyclone rather than any other weather system. The formation of the strong surface winds was caused not only by the intensive development of a cyclone, and the passage of a cyclonic cold front, but also by a strong meso-scale pressure gradient. The former closely accorded with the severe dust storm while the latter induced the severe prefrontal dust storm. The dust raising mechanism could be described in the following manner: after obtaining much momentum from strong surface winds, the dust was raised upward by strong turbulence in the PBL and then by the systemic ascending motion of a cyclonic system. In addition, divergence-pumping in the upper troposphere indirectly transplanted dust upward. |
