敦煌莫高窟顶几种典型床面蚀积量变化过程的初步观测

摘要/Abstract

摘要：

通过对莫高窟窟顶自然和人工床面的风蚀、输导及堆积沙量变化的野外监测,初步观测结果表明：在偏西风作用下,自然状况下的戈壁床面阻截了来自鸣沙山40％的沙量,其余60%的沙量进入窟区;而偏东风又可将偏西风、偏南风作用下沉积于窟顶90％的沙量吹回到鸣沙山边缘。床面阻、输性质与沙源供给状况密切相关。沙源丰富时,风沙流以较饱和形式输送,易形成输沙床面性质;沙源匮乏时,风沙流多以不饱和形式输送,形成阻沙-输沙床面性质。砾石直径较大（＞4 cm）的床面主要呈现堆积性质,对偏西的风沙流阻滞功效比较明显,每100 m阻沙率可达45％;偏东风作用下,每100 m阻沙率可达19％; 而砾石直径较小（1 cm）的床面,主要以风沙输沙功能为主,是一个非堆积搬运床面。

关键词: 莫高窟, 多风信, 砾石床面, 积沙量

Abstract: Monitoring of wind erosion and deposition on natural and artificial beds atop the Mogao Grottoes were performed. It was founded that 40 percent sands coming from the Minsha Mountain were arrested by the natural gobi bed in condition of westerly winds, and 60 percent else sands entered Mogao Grottoes areas; On the other hand, the 90 percent of sands deposited on top of the Mogao Grottoes could be blown back to the Minsha Mountain in condition of the Easterly winds. The sand bed pattern has close relationship with sands supply and winds. When sands supply is abundant, saturated sand streams transport, so a transporting bed is easily formed, whereas, a blocking-transporting sand bed is formed when sands supply is deficient. The beds with gravel diameter more than 4 cm mainly present depositing character; their sand-arresting rate can even reach 45 percent per 100 meter in condition of the Easterly wind, and 19 percent per 100 meter in condition of the Easterly winds. The bed with gravel diameter within 1 cm mainly presents transporting character, a non-depositing bed.

Key words: Mogao Grottoes, multi-wind environment, gobi bed, process of wind erosion and deposit

中图分类号:

X169

张伟民;汪万福;李志刚. 敦煌莫高窟顶几种典型床面蚀积量变化过程的初步观测[J]. 中国沙漠, 2008, 28(6): 1039-1044.

ZHANG Wei-min;WANG Wan-fu;LI Zhi-gang. Process of Wind Erosion and Deposition on Typical Beds atop Mogao Grottoes, Dunhuang, China[J]. JOURNAL OF DESERT RESEARCH, 2008, 28(6): 1039-1044.

参考文献

[1]兹纳门斯基A И.沙地风蚀过程的实验研究及沙堆防止问题[M].杨郁华,译.北京:科学出版社,1960:8-52.
[2]吴正,风沙地貌与治沙工程学[M].北京:科学出版社,2003:341-352.
[3]邹学勇,刘玉璋,吴丹,等.若干特殊地表风蚀的风洞实验研究[J].地理研究,1994,13（2）:42-48.
[4]McKenna N C.Particle transport and adjustments of the boundary layer over rough surfaces with an unrestricted,upwind supply of sediment[J].Geomorphology,1998,25:1-17.
[5]Zhang Weimin.The gobi sand stream and its control over the top surface of the Mogao Grottoes,China[J].Bulletin of Engineering Geology and the Environment,2004,63:261-269.
[6]屈建军,张伟民,彭启龙,等.有关敦煌莫高窟风沙问题探讨[J].地理学报,1996,51（5）：418-425.
[7]凌裕泉,屈建军,樊锦诗,等.敦煌莫高窟顶风沙危害研究[C]∥敦煌研究文集（上）.兰州：甘肃民族出版社,1993.
[8]屈建军,董光荣,文子祥,等.敦煌莫高窟风沙危害与防治问题[J].中国科学,1997,27（1）:82-95.
[9]张伟民,王涛,薛娴,等.敦煌莫高窟综合防护体系探讨[J].中国沙漠,2000,20（4）:409-414.
[10]Marshall J K.Measurements in roughness arrays of varying density and distribution[J].Agric Meteorol,1971,8:269-296.
[11]Lyles L,Schrandt R L,Schmeidler N F.How aerodynamic roughness elements control sand movement[J].Transactions of the ASAE,1974,17:134-139.
[12]McKenna N C,Nickling W G.Aeolian sediment flux decay:Nonlinear behavior on developing deflation lag surfaces[J].Earth Surf Process Landforms,1995,20:423-435.
[13]Dong Zhibao,Fryrear D W,Gao Shangyu.Modeling the roughness properties of artificial soil clods[J].Soil Science,1999,164 (12):930-935.
[14]Williams S H,Lee J A.Aeolian saltation transport rate:an example of the effect of sediment supply[J].Journal of Arid Environments,1995,30:153-160.
[15]Nickling W G,McKenna N C.Development of deflation lag surface[J].Sedimentology,1995,42:403-414.