古尔班通古特沙漠腹地输沙风能及地貌学意义

Wind Regime and Its Geomorphologic Significance in the Hinterland of Gurbantonggut Desert

根据古尔班通古特沙漠腹地2个气象台站2003-2006年气象资料,分析起沙风况和输沙势,并对其地貌学意义进行探讨。结果表明:沙漠中部全年起沙风出现频率为0.25%,以东北风和西北风为主;南部起沙风出现频率为0.11%,以西北风和西南风为主。沙漠中部和南部均属于低风能环境,中部地区的总输沙势(DP)为66.7VU,合成输沙势(RDP)为25.7 VU,合成输沙方向(RDD)为197.0°,方向变率指数为0.56;南部地区总输沙势(DP)为29.8 VU,合成输沙势(RDP)为16.3 VU,合成输沙方向(RDD)为108.4°,方向变率指数为0.65。沙漠中部4～10月输沙势占全年总输沙势的90%以上,其中7月的输沙势占全年的20%以上;沙漠南部输沙势主要集中于4～8月,约占全年的85%。沙漠中部受东北风和西北风的影响,与之相应的地面沙垄长而直,基本沿合成输沙方向延伸;沙漠南部受天山山脉的影响,主导风向转为西北和西南风,与之相应的地面沙垄开始向东偏转,并出现了副梁。

Gurbantonggut Desert is the largest fixed and semi-fixed desert in China.In this study a statistical analysis on wind regime and sand drift potential at two weather stations located in the hinterland of the Gurbantonggut Desert was carry out during the period from 2003 to 2006.The results are as follows： The occurring frequency of sand transport wind is 0.25% in the central area of the desert and 0.11% in the south area.The prevailing wind directions are northeast wind and northwest wind in the central area but southwest wind and northwest wind in the south area.In the central area,the sand drift potential（DP） and resultant sand drift potential（RDP） are 66.7 VU and 25.7 VU respectively,and the resultant sand drift direction（RDD） is 197.0°.DP and RDP in the south area are 29.8 VU and 16.3 VU respectively,and RDD is 108.4°.Both the central and south areas of the Gurbantonggut Desert belong to the low wind energy environment according to Fryberger＇s classification.Sand transport wind in the study area occurs mainly in spring and summer,the percentage of DP from April to October accounts for 90% in the central area,and that from April to August in the south area accounts for 85%.Affected by strong wind and corresponding wind directions（northeast and northwest） in the central area,the ridge of longitudinal dune-chains extends along the resultant wind direction,and the dune chains are high.Affected by southwest and northwest winds in the south area,an eastward deflexion of the ridge of longitudinal dune-chains occurs,and a subsidiary ridge appears.