关键词: 塔克拉玛干沙漠, 输沙势空间分布, 季节变化, 年际变化

Abstract: Taklimakan Desert is the largest sand desert in China, which is located in the Tarim Basin, Xinjiang. The rates of sand transport by wind plays the most important role in its aeolian surface processes. The “Fryberger Method” provides a useful and accessible way of evaluating the relative rates of sand transport (drift potential, DP) from measurements of wind data. With this method, a number of different estimations of DP about Taklimakan Desert have been proposed for the past decades. In this paper, we recalculated the DPs using the definition equation in which the arguments are the every measurements of wind velocity rather than the calculation model in which the arguments replaced by the midpoint of each velocity category, in order to clarify the cognition of the wind-energy environments in the sand sea. The calculations in the paper shows that the DP values of 22 meteorological stations ranged from 0.7 VU to 33.4 VU in 2007，thus the wind regimes should be classified into the Low-energy wind environments by using of the “Fryberger classification”.Based on the analysis of resultant drift potential (RDP),involving the RDP similarity (Cluster Analysis of Inner Product Similarity) and the region adjacency of a RDP type, the RDPs have been classified into five types，namely, Korla type in eastern Taklimakan with the RDPs showing W-S directions (abbr. W-S type), Xinhe type in the northern region as S type, Cele type in the western region as E type, Minfeng type in the southern region as E-NE type, and Special type with the RDPs at three stations being obviously different from their adjacent regions. The maximum average DP was caused by the NW wind regime, which happened in Cele type, and the lowest ratio of the directional variability of the winds (RDP/DP) was induced by the NE wind regime, which happened in Korla type. As a contrast,in the convergence zone between the NW and the NE wind regimes, the DPs was relative lower (Xinhe type with the minimum of DP),and the ratio of RDP/DP was higher (Minfeng type with the multi-direction effective winds) than the above two types. The cumulative DP from spring to summer in 2007 had reached to 81.29%-98.79% of the annual DP, only in May it accounted for 22.7% to 56.8% of the annual DP; whereas in winter except for February, almost no effective sand-driving winds had occurred over Taklimakan. In the southeast edge of the desert, under the normal weather condition, the northwest wind system moved eastwards between Qiemo and Ruoqiang County in May however it retreated back to the west of Tazhong region and between Minfeng and Qiemo in February. This indicated that the positions of the wind convergence zone under the strong wind weather were shifted eastwards. During the period from 2005 to 2007,the inter-annual variation of RDP showed as ±33% in magnitude and ±9.6° in direction as a whole; but some specific stations displayed larger variations of the RDPs, such as a variation of ±80% in magnitude at Aral station and a variation of ±24.4° in direction at Kuqa station.

Key words: Taklimakan Desert, spatial distribution characteristics of sand drift potential, seasonal change, inter-annual variation