古尔班通古特沙漠半固定沙垄表面风的脉动特征

摘要/Abstract

摘要： 利用DETI可移动测风系统,对古尔班通古特沙漠半固定沙垄进行实地观测,获取了主要风季沙垄表面7个典型部位200 cm高度的风向及距离地表20 cm、40 cm、60 cm、100 cm和200 cm 5个高度的风速系列数据。对风速和风向的脉动特征进行分析研究,发现凸起的沙垄不仅影响平均风速在沙垄表面的变化,亦对风速及风向脉动产生显著影响。结果表明,平均风速沿迎风坡逐渐增大,至垄顶达到最大,在背风坡中上部剧烈降低,随后又缓慢恢复。随着入射角的增大,平均风速在沙垄表面的变化幅度也在增大;绝对风速脉动具有与平均风速相同的变化趋势,且随距地表高度的增加绝对风速脉动值亦在增大;就相对风速脉动（阵性度值）而言,背风坡阵性度值要高于迎风坡,其中背风坡中上部是整个沙垄表面阵性度最高的部位,这与背风侧涡流的存在密切相关;沙垄背风坡风向脉动强度远比迎风坡大,随着入射角的减小,背风坡风向的偏转作用也在加强,而涡旋作用相对减弱。

关键词: 平均风速, 风速脉动, 风向脉动, 半固定沙垄, 古尔班通古特沙漠

Abstract: Field measurement of wind direction at 2-m height and wind velocity at five heights (0.2 m, 0.4 m, 0.6 m, 1 m and 2 m) over semi-fixed longitudinal dune was conducted in Gurbantunggut Desert in order to understand the characteristics of fluctuation of wind direction and velocity on dune surface. The dune morphology affects both the change of average wind velocity and fluctuation of wind direction and velocity. The average wind velocity increases up the stoss slope and decreases down the lee slope. With increasing of incidence angle, the change range of average wind velocity and fluctuation of absolute wind velocity increase, and the fluctuation increases with height. The fluctuation of relative wind velocity is greater on the lee slope than on the stoss slope because of existence of whirlpool on the lee slope. The fluctuation of wind direction on the lee slope is far stronger than on the stoss slope, and with the reduction of incidence angle, the deflexion of wind direction enhances, and the effect of the whirlpool weakens.

Key words: average wind velocity, wind velocity fluctuation, wind direction fluctuation, semi-fixed longitudinal dune, Gurbantunggut Desert

中图分类号:

P425.2

胡永锋;王雪芹*;郭洪旭;赵新军;盖世广;杨东亮;. 古尔班通古特沙漠半固定沙垄表面风的脉动特征[J]. 中国沙漠, 2011, 31(2): 393-399.

HU Yong-feng;WANG Xue-qin;GUO Hong-xu;ZHAO Xin-jun;GAI Shi-guang;YANG Dong-liang;. Wind Fluctuation over Semi-fixed Longitudinal Dune in Gurbantunggut Desert[J]. JOURNAL OF DESERT RESEARCH, 2011, 31(2): 393-399.

参考文献

[1]Skidmore E L.Soil erosion by wind[M]//El-Baz F,Hassan M H A.Physics of Desertification.Dordrecht:Martinus Nijhoff Publishers,1986:261-273.
[2]董治宝,李振山,严平.国外土壤风蚀的研究历史与特点[J].中国沙漠,1995,15(1):100-104.
[3]董治宝,高尚玉,董光荣.土壤风蚀预报研究述评[J].中国沙漠,1999,19(4):312-317.
[4]李振山,倪晋仁.挟沙气流输沙率研究[J].泥沙研究,2001(1):1-10.
[5]倪晋仁,李振山.挟沙气流中输沙量垂线分布的实验研究[J].泥沙研究,2002(1):30-35.
[6]贺大良.输沙量与风速关系的几个问题[J].中国沙漠,1993,13(2):14-18.
[7]吴正.风沙地貌与治沙工程学[M].北京:科学出版社,2003:16-21.
[8]Chepil W S,Siddoway F H.Strain-gauge anemometer for analyzing various characteristics of wind turbulence[J].Journal of Meteorology,1959,16:411-418.
[9]李振山,倪晋仁.风沙流中风速脉动的实验测量[J].应用基础与工程科学学报,2003,11(4):352-360.
[10]包慧娟,李振山.风沙流中风速纵向脉动的实验研究[J].中国沙漠,2004,24(2):244-247.
[11]Butterfield G R.Transitional behavior of saltation:wind tunnel observation of unsteady wind[J].Journal of Arid Environments,1998,39:377-394.
[12]Butterfield R G.Application of thermal anemometry and high-frequency measurement of mass flux to aeolian sediment transport research[J].Geomorphology,1999,29:31-58.
[13]Rasussen K.Some aspects of flow over coastal dunes[C]//Gimmingham C H,Ritchie W,Willetts B B,et al.Symposium:Coastal Sand Dunes.Royal Society of Edinburgh Proceedings,1989:96.
[14]张克存,屈建军,俎瑞平,等.典型下垫面风沙流中风速脉动特征研究[J].中国科学(D辑),2006,36(12):1163-1169.
[15]张克存,屈建军,董治宝,等.风沙流中风速脉动对输沙量的影响[J].中国沙漠,2006,26(3):336-340.
[16]Dong Z B,Qian G Q,Lu Ping,et al.Turbulence fields in the lee of two-dimensional transverse dunes[J].Earth Surface Processes and Landforms,2009,34(2):204-216.
[17]王雪芹,李丙文,张元明,等.古尔班通古特沙漠沙垄表面的稳定性与顶部流动带的形成[J].中国沙漠,2003,23(2):126-131.
[18]Wang X Q,Wang T,Jiang Jin,et al.On the sand surface stability in the southern part of Gurbantunggut Desert[J].Science in China(Series D),2004,34(8):763-768.
[19]Lancaster N.Linear dunes[J].Progress in Physical Geography,1982,6(4):475-504.
[20]Tsoar H.Dynamic processes acting on a longitudinal (seif) dune[J].Sedimentology,1983,30:567-578.
[21]Livingstone I.Geomorphological significance of wind flow patterns over a Namib linear dune[C]//Nickling W G.Aeolian Geomorphology.Boston:Allen and Unwin,1986:97-112.
[22]李志忠,关有志.纵向沙丘和横向沙丘模拟流场的实验研究[J].中国沙漠,1996,16(4):360-363.
[23]哈斯,董光荣,王贵勇.腾格里沙漠东南缘沙丘表面气流与坡面形态的关系[J].中国沙漠,1999,19(1):1-5.