关键词: 塔克拉玛干, 低空急流, 惯性震荡

Abstract:

The Taklimakan Desert is one of the important dust sources in the world. Using the ERA-Interim reanalysis data from 2000 to 2013, we analyzed the wind profile over the Taklimakan Desert and found a wind speed maximum center within the boundary layer under a mean stage. This indicates that a low-level jet (LLJ) may widely exist there all year long. In order to further analyze the seasonal variation of this LLJ that may exist in this region, we defined a criterion to identify the low-level jet by considering the height of maximum wind speed, temperature inversion and wind shear. The results show that there’s a easterly LLJ persistently appearing over this region, which had a high occurring frequency with the maximum (68.4%) in August and the minimum (54.5%) in December. Both the LLJ core height and maximum wind speed had a significant seasonal variation, in summer the height of LLJ was maximum with a mean value of 339.6 m above ground level, while in winter it was lowest with a mean value of 237.7 m and in spring and autumn, it was approximately situated at 294.0 and 280.1 m, respectively. The strongest LLJ core wind speed appeared in spring and summer with a value larger than 7.5 m/s, in autumn it decreased to 6.3 m/s, and it had a minimum value about 5 m/s in winter. Furthermore，the analysis shows a relationship between the core wind speed and height, the core wind speed increased with the height firstly, but then decreased after reaching a certain height range.

Key words: Taklimakan, low-level jet, inertial oscillation