地理科学进展  2016 , 35 (1): 98-107 https://doi.org/10.18306/dlkxjz.2016.01.011

Orginal Article

库布齐沙漠南缘抛物线形沙丘表面风沙流结构变异

陶彬彬, 刘丹, 管超, 哈斯额尔敦*

北京师范大学资源学院 北京 100875

Variation of aeolian sediment flux profiles on a parabolic dune at the southern fringe of the Hobq Desert

TAO Binbin, LIU Dan, GUAN Chao, HASI Eerdun*

College of Resource Science and Technology, Beijing Normal University, Beijing 100875, China

通讯作者:  哈斯额尔敦(1964-),男,教授,主要研究方向为干旱区地貌,E-mail: hasi@bnu.edu.cn

版权声明:  2016 地理科学进展 《地理科学进展》杂志 版权所有

基金资助:  基金项目:国家自然科学基金项目(41171002,41271020)

作者简介:

作者简介:陶彬彬(1989-),女,湖南邵阳人,硕士研究生,研究方向为风沙地貌,E-mail: taobb@mail.bnu.edu.cn

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摘要

对库布齐沙漠南缘抛物线形沙丘表面气流和输沙率的野外观测和分析结果表明,沙丘表面约90%的风沙输移集中在距沙面0.10 m高度范围内,输沙率随高度递减的形式在沙丘各部位因风速、下垫面状况和坡面形态不同而发生变异。沙丘迎风坡坡脚因出露坚硬、含砾石地表,颗粒跃移高度大,风沙流上层相对输沙率大;迎风坡沙粒沿坡向上运动,颗粒跃移高度减小,风沙流中近地表相对输沙率大;沙丘背风坡沙粒沿坡向下运动,加之来自丘顶变型跃移物质的影响,风沙流上层相对输沙率较大;脊线受迎风坡各个断面地形差异的影响,各观测点间风沙流结构差异显著。风沙流结构在迎风坡和丘顶均遵循指数递减规律(Q=aexp(-z/b)),其中,指数函数拟合中系数a与输沙率具有良好的幂函数关系,随风速增加而增加,但二者关系较弱;b与二者无相关性。背风坡风沙流结构具有明显的分段现象,以0.10 m高度为界,下层符合指数函数,上层符合幂函数。

关键词: 抛物线形沙丘 ; 风沙流结构 ; 函数拟合 ; 库布齐沙漠

Abstract

The airflow and sediment transport rate on the parabolic dune and the aeolian sediment flux profiles were examined in details in the southern Hobq desert in late April 2010 when the wind was strong and sediment movement was intense. The analyses show that 71%~91% sediments moved in the space between 0 and 0.10 m above surface. This confirms the results of previous research that blown sand activity occurs near bed. Due to the difference of wind velocity, underlying surface conditions, and slope profiles, sediment transport rate and relative sediment transport rate vary, so do the aeolian sediment flux profiles. At the measurement spots where wind velocity and sediment transport rate are small, such as the toe and the lower part of the windward slope, the aeolian sediment flux profiles vary considerably. Underlying surface condition is a vital factor influencing aeolian sediment flux profile. At the windward toe that suffers deflation, the gravelly surface is hard. This contributes to sediments’ saltaltion, so sediment transport rate is relatively high at the upper layer of the aeolian sediment flux profile. Along the windward slope, sediments move upward and have a lower saltation height. Therefore sediment transport is relatively high near surface. In contrast, sediments move downward at brink-line on the leeward slope with higher height and the trajectories deform, so the saltation height is higher. Affected by the difference of windward slope profile shape, the aeolian sediment flux profiles at the crest vary markedly among the measurement spots. In spite of the variation of the aeolian sediment flux profiles, they can still be well described by the exponential decay law at the windward slope and crest. In the equation Q=aexp(-z/b), the coefficient a has an apparent power function correlation with sediment transport rate and increases simultaneously with wind velocity, but there is no clear correlation between them. The coefficient b has no significant correlation with these two factors. At the brink-line, the profiles were segmented at the 0.10 m height: the profiles of near surface follow exponential decay while the upper layers obey power function.

Keywords: parabolic dune ; aeolian sediment flux profile ; function fitting ; Hobq Desert

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陶彬彬, 刘丹, 管超, 哈斯额尔敦. 库布齐沙漠南缘抛物线形沙丘表面风沙流结构变异[J]. , 2016, 35(1): 98-107 https://doi.org/10.18306/dlkxjz.2016.01.011

TAO Binbin, LIU Dan, GUAN Chao, HASI Eerdun. Variation of aeolian sediment flux profiles on a parabolic dune at the southern fringe of the Hobq Desert[J]. 地理科学进展, 2016, 35(1): 98-107 https://doi.org/10.18306/dlkxjz.2016.01.011

1 引言

风沙流结构,即输沙量随高度的分布形式和变化规律,是近地面输沙强度评估和防沙治沙工程布设的重要参数之一(吴正等, 2010)。自20世纪40年代以来,随着野外观测技术的不断进步、风洞实验的逐渐完善以及计算机模拟技术的高速发展,各国学者在风沙流结构研究中取得了丰硕成果。近年来,中国学者对风沙流结构进行了大量野外观测和风洞实验,如在戈壁(尹永顺, 1989; 邹学勇等, 1995; 屈建军等, 2005; 张克存等, 2005)、塔克拉玛干沙漠(杜鹤强等, 2012; 韩致文等, 2012; 杨兴华等, 2012)、腾格里沙漠(哈斯, 2004; 张正偲等, 2013; Dong et al, 2014)、乌兰布和沙漠(何京丽等, 2012; 刘芳等, 2014)、毛乌素沙地(吴晓旭等, 2011; 包岩峰等, 2013)、浑善达克沙地(刘树林等, 2006; 张广等, 2006)、科尔沁沙地(张华等, 2002)、华北耕地(哈斯, 1997; 王仁德等, 2009; 牛艳频, 2011)、东部海岸(陈方等, 1997; 董玉祥等, 2008, 2009)等进行的研究,探讨了风速、输沙量以及下垫面状况对风沙流结构的影响。一般认为,风沙流结构呈指数函数(Williams, 1964; Anderson et al, 1988,Dong et al, 2014)或幂函数(Fryrear et al, 1991; 何京丽等, 2012)形式,随下垫面等因素的改变,风沙流结构发生不同程度的变异,呈多项式甚至分段函数形式。例如,受地表沉积物粒度影响,戈壁地表甚至新月形沙丘表面的风沙流结构出现“象鼻效应”(屈建军等, 2005; 张克存等, 2005; 杜鹤强等, 2012; 韩致文等, 2012);受地表植被影响,风沙流中输沙率随高度递减速度小,风沙流结构出现“双峰”现象(刘树林等, 2006)。但目前尚未发表关于库布齐沙漠地表风沙流结构的研究报告。

已有的实验观测通常在风洞或者野外平坦地表(沙丘丘顶或丘间地)进行,关于沙丘坡面上不同部位的风沙流结构(哈斯, 2004; 杜鹤强等, 2012; 韩致文等, 2012; Dong et al, 2014)研究尚不充分。沙丘坡面地形的抬升作用使气流发生变异,近地表风速廓线偏离对数,所得风速不能准确计算与输沙率密切相关的表面剪切风速;加之受沙源丰寡的影响,风速与输沙率的关系明显改变。因此,受坡面气流和沙源的共同影响,风沙流结构发生变异,这将直接影响当地输沙强度的计算精度以及防沙治沙工程布设的有效性(Butterfield, 1999; Rotnicka, 2013)。因此探究不同环境中风沙流结构的变异情况在沙漠化治理中具有重要的理论和应用价值。

由于界面尺度的限制,目前还不能在风洞中开展较大沙丘的模拟实验,在野外对风沙流结构进行直接观测仍是获取实测资料和检验理论的重要手段。本文在库布齐沙漠南缘对典型抛物线形沙丘表面风沙流结构进行观测,探讨了该类型沙丘表面风沙流结构特征及其变异程度,以及用风沙流结构拟合函数进行输沙率估算的精度,以期为库布齐沙漠的防沙治沙工程提供一定理论依据。

2 研究区域概况和研究方法

2.1 研究区域概况

研究区位于库布齐沙漠南缘的覆沙台地,地势南高北低,平均海拔1238 m,地表景观以油蒿灌丛地、片状沙丘地与多条由暂时性流水沟谷相间为特色。该区属温带荒漠草原气候,根据杭锦旗气象站多年观测数据,年均温为5.7 ℃,年均降水量为277 mm且集中于夏季,年均蒸发量为2400 mm,全年盛行WNW风,年均风速3.5 m·s-1,年均大风天数为30 d,风沙活动主要发生在3-5月,输沙势(DP)为201.60 VU,合成输沙势(RDP)为142.99 VU,合成输沙方向为111.38°。

观测沙丘为典型抛物线形沙丘,位于一条南北走向干河床东侧,四周被油蒿灌丛包围(图1)。沙丘平面形态呈向西开口的U型,南北两翼近乎平行,走向为WNW-ESE,与合成输沙方向一致,沙丘长230 m,宽138 m,高约3 m。根据该沙丘的形态特征,可分为前端活动区、南北两翼和翼间平地等三个地貌单元。前端活动区为裸沙区,基本无植被覆盖,迎风坡坡度在3~12°之间;背风坡发育小型滑落面,丘顶与滑落面之间平而缓(0~4°);南、北两翼内侧坡较缓(2~8°)无植被,外侧坡较陡(6~15°)且坡脚到翼脊分布油蒿灌丛,南翼已发育油蒿灌丛沙丘;翼间平地发育不同年龄阶段的油蒿灌丛,在接近沙丘坡脚的裸露地表比较坚硬且有蚀余碎石散布。沙丘沉积物以细、中砂为主,平均粒径为0.185 mm,分选较好(图2)(吴霞等, 2012) 。

2.2 研究方法

风沙观测于2010年4月下旬进行,当时研究区正处于风沙活动强烈的时期。风速观测采用长春气象局研制的三杯风速传感器,风杯距地表高度0.40 m,数据采集系统为美国坎贝尔公司生产的CR1000,观测期间风向为WNW-NW;输沙率观测仪器为原中国科学院兰州沙漠研究所研制的阶梯式集沙仪,可观测0.02 m宽度和距地表0.20 m高度范围内的输沙通量。为避免集沙仪对气流的干扰,每个观测点处的集沙仪与风速计相距1.00 m。

抛物线形沙丘表面形态复杂,故选择不同特征断面进行观测(图1),图中A-G分别表示脊线的7个观测点,H-L分别表示前端活动区的迎风坡坡脚、迎风坡下部、迎风坡上部、丘顶和滑落面顶,P(p)-T(t)依次表示翼角北侧坡脚、北侧坡中、翼顶、南侧坡中、南侧坡脚。由于仪器数量有限,观测按不同地貌单元分三次进行:前段活动区的3个纵断面、两翼和脊线,其中3个纵断面同时观测,共进行四次观测,时间为12:16-15:01;两翼进行两次观测,时间为同日16:35-17:35,脊线进行两次观测,时间为次日11:11-12:12,每次观测时间依据风速大小决定,风速与输沙率观测同步进行。集沙物质用自封袋分层收集,在室内自然晾干后用电子天平称重(精度为0.001 g)并记录,获得每层单宽输沙率(单位为g·m-1·s-1)。距地表0.40 m的起沙风速3.20 m·s-1,因此选取大于3.20 m·s-1的风速作为有效风速。

图1   研究区地理位置和抛物线形沙丘及观测点位示意图

Fig.1   Location of the study area and the parabolic dune with measurement spots

图2   沙丘表面沉积物粒度频率图(吴霞等, 2012)

Fig.2   Grain size composition of surface sedimentary particles on the parabolic dune(Wu et al, 2012)

3 结果与分析

表1是沙丘不同部位风沙流结构的平均状况。输沙率和风速沿迎风坡向上依次增加,至丘顶达到最大值,在滑落面顶减小。除坡脚外,沙丘前端活动区各纵断面上其他部位输沙率随高度变化趋势相似,距地表0.04 m内的相对输沙率为68%~72%,0.10 m内的为91%~93%,风沙流结构上层稳定;坡脚输沙率随高度增加的递减程度小,约48%的输沙率集中在近地表0.04 m内,77%集中在0.10 m内。脊线上各观测点风沙流结构也存在差异,距地表0.04 m内的相对输沙率42%~79%,0.10 m内的为77%~97%,波动程度大。两翼上,南翼两侧坡面输沙率差异远大于北翼,北翼和南翼距地表0.04 m内的相对输沙率比例分别为53%~80%、39%~69%,0.10 m内的为80%~95%、71%~92%,且两翼南侧近地表的相对输沙率均较北侧大。整体上,随输沙率增加,距地表0.10 m内的相对输沙率增加。

表1   抛物线形沙丘不同部位的相对输沙率

Tab.1   Relative sediment transport rate of different positions on the parabolic dune

高度 /m前端活动区相对输沙率/%脊线相对输沙率/%
H*IJKLABCDEFG
0.0129.9444.8843.1841.0749.8040.7729.8554.4253.1722.1256.9133.83
0.0318.2922.8927.7127.2821.7921.0722.2924.5719.7519.5919.4018.41
0.0513.1612.1012.2613.0810.6713.7715.1810.7711.3816.549.0110.95
0.079.306.986.076.955.838.9410.214.905.8112.954.977.77
0.097.414.143.603.933.425.717.152.503.379.653.196.15
0.116.662.722.362.602.353.515.291.252.236.702.265.20
0.134.772.101.601.781.822.483.660.671.534.631.505.25
0.153.851.571.251.341.601.672.750.421.163.441.104.35
0.173.391.341.031.051.411.182.030.280.882.480.944.04
0.193.221.280.940.911.330.911.580.230.711.910.724.04
总输沙率/(g·m-1·s-1)2.857.0413.5016.949.720.971.755.532.408.664.330.64

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表1(续)   抛物线形沙丘不同部位的相对输沙率

Tab.1   Relative sediment transport rate of different positions on the parabolic dune

高度/m北翼相对输沙率平均值/%南翼相对输沙率平均值/%
PQRSTpqrst
0.010.2930.3260.4450.6100.3520.2240.3860.3350.3970.452
0.030.2330.2260.2650.1930.2160.1620.2260.2180.2970.185
0.050.1280.1520.1300.0830.1350.1260.1300.1470.1230.095
0.070.0840.0950.0650.0400.0860.1000.0850.0990.0640.068
0.090.0650.0600.0350.0240.0640.1000.0580.0670.0390.048
0.110.0480.0460.0210.0160.0440.0620.0390.0450.0270.040
0.130.0430.0320.0130.0110.0340.0520.0290.0340.0180.032
0.150.0390.0250.0100.0090.0270.0570.0210.0230.0140.030
0.170.0340.0210.0080.0070.0240.0630.0150.0180.0120.026
0.190.0330.0180.0070.0070.0190.0550.0120.0130.0090.025
总输沙率/(g·m-1·s-1)0.919.8813.457.572.440.325.7126.1421.303.76

注:*表格中各字母代表沙丘不同部位的观测点,具体位置如图1所示。

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图3为沙丘各部位风沙流结构情况。从图3可以看出,各个观测部位的风沙流结构均发生不同程度变异,随输沙率或者风速减小,风沙流结构变异程度增加。前端活动区3个纵断面的风沙流结构各不相同,坡面上各点风沙流曲线接近直线,丘顶输沙率大,输沙率随高度递减程度大;坡脚风速小、输沙率小,输沙率随高度递减速度慢且风沙流结构较紊乱;背风侧的滑落面顶,风沙流结构具有明显的分段现象,距地面0~0.08 m内呈直线,0.08 m以上呈非直线。在脊线,当风速较大时,风沙流结构在近地表为指数偏小型,风速小时为指数偏大型。在两翼,不同部位风沙流曲线大致平行,风沙流结构差异显著。

图3   沙丘各部位风沙流结构

Fig.3   Aeolian sediment flux profiles of different positions on the dune

虽然沙丘各部位风沙流结构发生变异,但整体上仍符合指数函数(Q=aexp(-z/b))递减规律(表2),观测点中函数拟合优度大于0.95(P<0.01)约91%。其中,a,b为拟合系数,a的取值范围为0.07~12.07,最大值和最小值都出现在南翼;b的取值范围为0.02~0.10,最大值出现在南翼北侧坡脚,最小值出现在北翼南侧坡中。研究认为,沙丘背风坡的风沙流结构下层为指数函数,上层为幂函数(哈斯, 2004)。根据半对数图上背风坡风沙流结构特点,以0.08~0.10 m为界进行分段拟合,结果显示(表3),分段拟合提高了风沙流结构下层的拟合精度,降低了上层的拟合精度。

表2   沙丘不同部位风沙流结构的函数拟合情况

Tab.2   Results of the regression analyses for the aeolian sediment flux profiles

沙丘部位观测点位V/(m-1·s-1)Qm/(g·m-1·s-1)abQC1QC1-QmR2
北断面H6.225.511.9180.0565.214-0.3010.95
I6.577.355.2950.0276.934-0.4191.00
J7.039.485.1140.0389.5370.0580.98
K7.8621.9212.0350.03721.9670.0430.99
L7.3110.977.5310.02810.145-0.8280.99
中轴断面H6.632.800.8280.0712.757-0.0470.99
I6.969.876.3010.0309.362-0.5071.00
J7.2311.987.6370.03211.977-0.0010.99
K7.4515.019.7400.03014.548-0.4621.00
L7.149.486.5130.0288.996-0.4851.00
南断面H6.350.250.0790.0620.235-0.0110.95
I7.323.901.8820.0413.759-0.1440.99
J8.0019.059.3790.04018.370-0.6761.00
K8.4113.895.9210.04814.0070.1120.96
L7.178.704.7240.0368.269-0.4350.99
北翼P5.540.910.3330.0550.883-0.0240.97
Q5.949.883.9890.0509.739-0.1371.00
R6.3713.458.4020.03213.335-0.1161.00
S5.827.577.4090.0207.030-0.5451.00
T5.592.441.0120.0482.363-0.0770.99
南翼p5.640.320.0720.1040.318-0.0010.99
q7.665.712.7110.0415.482-0.2240.99
r8.9326.1410.3960.05226.081-0.0631.00
s7.0521.3012.0750.03520.986-0.3120.99
t3.483.762.2190.0303.244-0.5200.96
脊线A4.700.970.4730.0410.950-0.0211.00
B4.921.750.6190.0591.7490.0031.00
C6.155.534.4280.0255.493-0.0391.00
D5.862.401.9100.0242.229-0.1730.99
E5.988.662.2900.0858.8060.1470.97
F6.044.333.9370.0213.962-0.3710.99
G5.060.640.2530.0470.583-0.0610.93

注:a,b为风沙流结构的指数函数拟合系数,Qm为观测输沙率,Qc1为指数函数计算所得输沙率,R2为拟合优度。

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表3   滑落面顶分段函数拟合与连续函数拟合结果的对比

Tab.3   Comparison between continuous exponential function and discontinuous function for aeolian sediment flux profiles at the dune brink

观测
断面
连续函数分段函数
Qm0~0.20 m
指数
Qc10~0.10 m
指数
0.10~0.20 m
幂函数
Qc2
N10.7970.99210.1450.9980.96910.886
M9.3670.9968.9960.9990.9529.426
S8.5630.9918.2690.9930.9738.656

注:Qc1为单一指数函数计算所得输沙率,Qc2为以0.01 m高度为界的分段函数计算所得输沙率。

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4 讨论

风速(Butterfield, 1999; 董玉祥等, 2009)、沙源供应量(张伟民等, 2009)、下垫面状况(Lancaster et al, 1998; 陈智等, 2010)等因素通过影响地表输沙量而改变风沙流结构。沙丘表面的情况更加复杂,风沙流结构由沙丘形态特征、微地貌以及风沙运动的力学性质共同决定(韩致文等, 2012)。

地表起伏改变沉积物颗粒跃移轨迹,沿坡向上运动时,颗粒跃移高度小于平坦地表,风沙流下层输沙率相对增加,上层则相对减小(Iversen et al, 1994; 哈斯, 2004),故迎风坡的输沙率随高度的递减速度大。迎风坡坡脚因沙丘前移而出露平坦坚硬的含砾石地表,增大了沉积物跃移高度,风沙流上层相对输沙率增加,输沙率随高度的递减速度减小。丘顶到背风侧滑落面顶坡面平缓,下坡运动趋势小,跃移高度增加不明显,加之风速减小,近地表相对输沙率增加。地表起伏形态影响风沙流结构(吴正等, 2010)。迎风坡3个纵断面之间地形起伏情况和各观测点的微地貌不同,故即使同一部位的风沙流结构也存在差异。气流具有呈股流沿坡向上流动的特征(Baas et al, 2005; Baas, 2008),脊线上各观测点受气流股流结构的影响程度不同,故风沙流结构存在显著差异且发生不同程度变异。受抛物线形沙丘形态特征的影响,盛行风与两翼脊线小角度斜交甚至平行,使得两翼具有线形沙丘动力学性质,背风坡发生侧蚀。翼角北侧为迎风坡,受上风向植被的屏障作用,风沙流中含沙量小,风沙流下层相对输沙率小,故输沙率递减速度小;南侧为背风坡,旁侧气流的存在加强了翼角南侧坡脚的侵蚀作用,同时,颗沉积物粒沿翼脊走向输移,跃移高度变化,相对输沙率在近地表大,在风沙流上层小,故输沙率递减速度大。

库布齐沙漠抛物线形沙丘表面风沙流结构变异程度小。与塔克拉玛干沙漠新月形沙丘(细沙和极细沙为主)相比,库布齐沙漠抛物线形沙丘表面沙物质粒径(细沙和中沙为主)较大(王训明等, 2001; 吴霞等, 2012);韩致文等在新月形沙丘迎风坡坡脚和丘顶发现“象鼻效应”,但我们没有在抛物线形沙丘上(包括迎风坡坡脚)观察到“象鼻效应”。沙丘两翼的风沙流结构受灌丛影响发生变异,但未出现半固定沙地上的双峰现象(刘树林等, 2006)。该沙丘背风坡的风沙流结构具有分段现象,这与哈斯(2004)、杜鹤强等(2012)的研究结果一致。

输沙率随高度增加减小是毋庸置疑的事实,但关于风沙流结构的具体形式众说纷纭。相对风洞实验而言,风沙流野外观测的结果复杂多变,蠕移质、沉积物粒度和地表粗糙度等因素都导致风沙流结构发生较大程度变异而偏离指数函数形式(Butterfield, 1999; Ni et al, 2003)。许多学者提出分段拟合风沙流结构,并得出各种形式的分段函数(哈斯, 1997; 董玉祥等, 2009; 韩致文等, 2012)。

根据半对数坐标图上风沙流结构曲线特征,选择单一指数函数方程进行拟合,效果良好(表2)。不同的学者对指数函数(Q=aexp(-z/b))中系数a,b有不同的见解。其中a的物理意义尚未明确,有研究认为a代表风沙流中蠕移质的含量(Dong, 2002; Zheng, 2004; Dong et al, 2014)或者风沙流浓度的最大值(王洪涛等, 2004);1/b为输沙率随高度的递减率,反映风沙流结构中输沙率变化的整体趋势。风洞实验结果认为,a随风速增加而减小,b则相反(Dong et al, 2007)。但是,在复杂的自然环境中,ab与风速和输沙率的关系发生变化(图4)。a随风速变大呈增加趋势,与输沙率具有良好的幂函数关系;与观测输沙率Qm的比值范围为23%~98%,显然,a不可能代表蠕移质的含量。b值与风速和输沙率均无相关性,间接说明b还受其他因子的影响,如沙丘表面地表粗糙度、地表湿度和沉积物粒径等下垫面状况。但是,将沙丘前端活动区的风速、输沙率、ab值取均值后发现,各参数的变化趋势具有良好的同步性(表4)。可见,风沙流结构特征及其与风速、输沙率的关系是气流与地表长期作用的结果,若数据采集时间间距过短,数据噪音干扰大,可能掩藏风沙流结构与风速和输沙率等变量的关系,因而适当延长观测时间和数据采集步长有助于揭示风沙流结构变化规律。

图4   指数函数拟合系数(a,b)与风速和输沙率的关系

Fig.4   Relationship between the parameters (a and b) and wind velocity and sediment transport rate

表4   前端活动区风沙流结构拟合函数系数a,b的均值与风速和输沙率均值的关系

Tab.4   Relationship between the average values of the parameters a and b of regression analyses with exponential function and wind velocity and sediment transport rate at the dune’s nose

观测点位V/(m·s-1)Q/(g·m-1·s-1)ab
H6.402.850.9420.063
I6.957.044.4930.033
J7.4213.507.3770.037
K7.9116.949.2320.039
L7.219.726.2560.030

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沙丘表面输沙率与风沙流高度呈函数关系,沙粒的平均跃移高度反映风沙流的跃移强度,通过以下公式,可得出沙粒平均跃移高度与系数b的关系,进而了解风沙流的跃移强度:

H̅=0Qhhdh0Qhdh=b[1-(1+1b)e-1b]1-e-1bbe-1b1

式中: H̅为平均跃移高度;h为风沙流高度;Q(h)为输沙量;d(h)是指积分标志。由上式可知,跃移高度与系数b的分布情况一致,即系数b为平均跃移高度的近似值(张正偲等, 2013)。据此可知,该沙丘表面沙粒跃移高度范围为0.02~0.10 m。坡脚地表坚硬,沙粒的反弹作用大,跃移高度大,因此b值大;而沙丘坡中部位,受地表坡度和缺乏水分等多因素共同影响,沙粒跃移高度小,即b值小。

图5   指数函数拟合结果的精确度

Fig.5   Accuracy of regression analyses with exponential function

用风沙流结构的拟合函数所计算的输沙率(Qc)与观测输沙率(Qm)具有良好的线性关系(图5),说明指数函数对风沙流结构的拟合效果好。Rotnicka(2013)在波罗的海南部海岸的实验结果认为,风速大或者地表湿度大会导致拟合函数低估实际值(Qc-Qm<0)。本实验发现沙丘各个部位用单一指数函数方程计算所得的输沙率均低于实际输沙率;背风侧滑落面顶的风沙流结构用分段函数进行拟合,计算所得的输沙率与观测输沙率的差值Qc2-Qm>0,即分段函数方程计算结果高于实际输沙率,与用单一指数函数方程计算所得结果相反,且Qc2更接近Qm,即拟合函数对输沙率的低估或高估还与选用的函数形式有关,在沙丘背风侧用分段函数估算的输沙率精确度相对较高。

5 结论

根据上述分析与讨论,初步得出以下结论:

(1) 抛物线形沙丘沙源短缺,沙丘表面约62%输沙率集中在近地表0.04 m以内,约88%集中在0.10 m以内,总输沙率越大,风沙流下层相对输沙率越大,与平坦地表结论一致。说明无论沙源丰寡,风沙流都是一种贴近地表的沙物质搬运现象。

(2) 该沙丘表面各部位风沙流结构发生不同程度的变异,但各个部位发生变异的主导因素不尽相同:坡脚受坚硬的砾石地表影响;迎风坡受沙丘表面下垫面状况影响;背风坡以风速为主导因素;脊线上影响因素复杂,不仅受立地条件的影响,还受其所在坡面地形起伏的影响。

(3) 风沙流结构拟合函数的具体形式影响输沙率估计值精度。用指数函数拟合变异后的整体风沙流结构,其拟合优度高,但所得输沙率总是低于实际值。背风侧滑落面顶风沙流结构分段,大致以0.10 m为界,下层符合指数函数规律,上层符合幂函数递减规律,分段函数计算所得输沙率估算精度比单一指数函数高。风沙流结构指数函数拟合结果的系数ab,a取值范围为0.07~12.07,变化幅度大,与输沙率呈幂函数关系,随风速增加而增加,但无法表示蠕移质含量;b的取值范围为0.02~0.10,与风速或输沙率无显著相关性,能近似表示跃移高度,在地表坚硬的坡脚,b值大;在干燥疏松的迎风坡坡中和两翼坡中小,b值小。

The authors have declared that no competing interests exist.


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土壤风蚀是中国北方干旱半干旱地区农田土地退化的重要原因。该文利用移动式风蚀风洞对保护性 耕作农田和传统翻耕农田进行原位测试,对比分析保护性耕作农田地表风沙流特性,探讨保护性耕作对土壤风蚀的影响机理,为防治农田土壤风蚀提供理论依据。研 究表明,与对照秋翻地相比,由于直立残茬的作用,保护性耕作农田能迅速降低近地表风速,特别是在残茬高度内改变了风速随高度变化的对数规律,风速随高度的 降低而急剧减小。其风沙流结构也发生了明显变异,风沙活动层主要集中在180~400mm高度范围内,占总输沙量的67.94%~69.28%,最大输沙 率出现在距地表240mm高度上,风沙流结构呈现出类似象鼻形状的"象鼻效应"。风沙流总输沙率也明显小于对照秋翻地,保护性耕作是一种防治农田风蚀沙化 的有效耕作措施。
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[J]. 地理科学, 28(4): 507-512.

https://doi.org/10.3969/j.issn.1000-0690.2008.04.009      URL      Magsci      [本文引用: 1]      摘要

选择中国规模最大、形态最为典型的河北昌黎黄金海岸的横向沙脊,采用野外梯度风速仪和平口式积沙仪对其顶部的风沙流结构进行了观测。观测结果表明,海岸横向沙脊表面的风沙流结构特征基本表现为0~40cm高程内气流搬运的沙尘物质浓度或质量随高度递减并符合指数分布,20~60cm高程内符合幂函数分布,40~60cm高程内输沙量与高度之间则为多项式函数关系。同时,海岸横向沙脊表面的风沙流结构受风速与总输沙量的影响较大,随风速增大或总输沙量的增加,风沙流下层输沙量相对减少、上层则相应增加。

[Dong Y X, Hesp P A, Namikas S L, et al.2008.

Field measurements of structure of wind-sand flow on coastal transverse ridge in China

[J]. Scientia Geographica Sinica, 28(4): 507-512. ]

https://doi.org/10.3969/j.issn.1000-0690.2008.04.009      URL      Magsci      [本文引用: 1]      摘要

选择中国规模最大、形态最为典型的河北昌黎黄金海岸的横向沙脊,采用野外梯度风速仪和平口式积沙仪对其顶部的风沙流结构进行了观测。观测结果表明,海岸横向沙脊表面的风沙流结构特征基本表现为0~40cm高程内气流搬运的沙尘物质浓度或质量随高度递减并符合指数分布,20~60cm高程内符合幂函数分布,40~60cm高程内输沙量与高度之间则为多项式函数关系。同时,海岸横向沙脊表面的风沙流结构受风速与总输沙量的影响较大,随风速增大或总输沙量的增加,风沙流下层输沙量相对减少、上层则相应增加。
[5] 董玉祥, 马骏. 2009.

风速对海岸沙丘表面风沙流结构影响的实证研究

[J]. 干旱区资源与环境, 23(9): 179-183.

URL      [本文引用: 3]      摘要

在河北昌黎黄金海岸形态典型的横向沙脊顶部,对不同风速下的风沙流结构进行了观测。结果表 明:随着风速的增加,风沙流中40cm高度内的绝对输沙量增加,40~60cm高度内各层的绝对输沙量减少;相对输沙量,在0~4cm高度内减 少,4~20cm高度内增加,20~44cm高度内变化较小,44—60cm高度内减少;风沙流结构模式在0~40cm高程内为指数分布,但在 0~60cm高程内随风速增大由幂函数分布转变为指数函数分布,在40~60cm高程内则转变为相关性更强的多项式函数分布。风速变化对风沙流结构的上述 影响,主要与随风速增加增大了沙粒的搬运高度以及气流搬运沙物质的粒度组成有关。

[Dong Y X, Ma J.2009.

Field measurements of influence of total sand transport rate on the structure of wind-sand flow on the coastal transverse ridge

[J]. Journal of Arid Land Resources and Environment, 23(9): 179-183.]

URL      [本文引用: 3]      摘要

在河北昌黎黄金海岸形态典型的横向沙脊顶部,对不同风速下的风沙流结构进行了观测。结果表 明:随着风速的增加,风沙流中40cm高度内的绝对输沙量增加,40~60cm高度内各层的绝对输沙量减少;相对输沙量,在0~4cm高度内减 少,4~20cm高度内增加,20~44cm高度内变化较小,44—60cm高度内减少;风沙流结构模式在0~40cm高程内为指数分布,但在 0~60cm高程内随风速增大由幂函数分布转变为指数函数分布,在40~60cm高程内则转变为相关性更强的多项式函数分布。风速变化对风沙流结构的上述 影响,主要与随风速增加增大了沙粒的搬运高度以及气流搬运沙物质的粒度组成有关。
[6] 杜鹤强, 韩致文, 王涛, . 2012.

新月形沙丘表面风速廓线与风沙流结构变异研究

[J]. 中国沙漠, 32(1): 9-16.

URL      Magsci      [本文引用: 3]      摘要

在风沙地貌学中,跃移沙粒与风 场的耦合作用下,其最直观的表现形式为风速廓线和风沙流结构的变异。通过对塔克拉玛干沙漠腹地新月形沙丘迎风坡坡脚、沙丘顶部、沙丘的两个兽角前端、沙丘 背风坡坡脚5个典型部位的风速廓线和风沙流结构进行了实地观测,并与参照点(丘间粗沙地)的风速廓线和风沙流结构进行了对比。发现受地形扰动作用,沙丘背 风坡坡脚处和沙丘的两个兽角前端的风速廓线形式均呈现非对数形式分布。除迎风坡坡脚处风沙流结构与参照点处相似之外,其余各个部位风沙流均表现出不同于参 照点的结构形式。直接采用曲线拟合方法对风沙流结构函数进行拟合,并针对有明显分段现象的风沙流结构形式,采取分段拟合,并对造成风速廓线和风沙流结构变 异的原因进行了讨论。

[Du H Q, Han Z W, Wang T, et al.2012.

Variation of wind profile and sand flow structure above Barchan Dune

[J]. Journal of Desert Research, 32(1): 9-16. ]

URL      Magsci      [本文引用: 3]      摘要

在风沙地貌学中,跃移沙粒与风 场的耦合作用下,其最直观的表现形式为风速廓线和风沙流结构的变异。通过对塔克拉玛干沙漠腹地新月形沙丘迎风坡坡脚、沙丘顶部、沙丘的两个兽角前端、沙丘 背风坡坡脚5个典型部位的风速廓线和风沙流结构进行了实地观测,并与参照点(丘间粗沙地)的风速廓线和风沙流结构进行了对比。发现受地形扰动作用,沙丘背 风坡坡脚处和沙丘的两个兽角前端的风速廓线形式均呈现非对数形式分布。除迎风坡坡脚处风沙流结构与参照点处相似之外,其余各个部位风沙流均表现出不同于参 照点的结构形式。直接采用曲线拟合方法对风沙流结构函数进行拟合,并针对有明显分段现象的风沙流结构形式,采取分段拟合,并对造成风速廓线和风沙流结构变 异的原因进行了讨论。
[7] 哈斯. 1997.

河北坝上高原土壤风蚀物垂直分布的初步研究

[J]. 中国沙漠, 17(1): 9-14.

URL      Magsci      [本文引用: 2]      摘要

根据河北坝上高原农田土壤风蚀 物的观测与采样分析结果,风蚀物含量随高度的增加,在0~20cm高度内以指数函数规律递减,反映了以跃移质为主的风沙流结构;在20~100cm高度内 以幂函数规律递减,反映的是悬移质为主的风沙流结构。在风蚀物粒度组成中,随高度增加,砂级颗粒含量减少而粉砂及粘土含量增多;随风速与输沙率的增加,砂 级颗粒含量增多而粉砂及粘土含量减少。对风蚀物各粒级含量与高度的相关分析表明:易以迁移形式运动的粒径0.25~0.1mm土粒百分量以幂函数形式向上 递减;沉降速度较低的粒径<0.1mm土粒百分含量成幂函数形式向上递增。此外,风蚀物平均粒径随高度变细且在50cm处细于0.1mm,因此,土壤颗粒 成为悬移物质而上升到50cm以上高度时可能搬运到较远的地区

[Hasi E.1997.

Preliminary study on the vertical distributions of wind dust over Bashang plateau, Hebei Province

[J]. Journal of Desert Research, 17(1): 9-14.]

URL      Magsci      [本文引用: 2]      摘要

根据河北坝上高原农田土壤风蚀 物的观测与采样分析结果,风蚀物含量随高度的增加,在0~20cm高度内以指数函数规律递减,反映了以跃移质为主的风沙流结构;在20~100cm高度内 以幂函数规律递减,反映的是悬移质为主的风沙流结构。在风蚀物粒度组成中,随高度增加,砂级颗粒含量减少而粉砂及粘土含量增多;随风速与输沙率的增加,砂 级颗粒含量增多而粉砂及粘土含量减少。对风蚀物各粒级含量与高度的相关分析表明:易以迁移形式运动的粒径0.25~0.1mm土粒百分量以幂函数形式向上 递减;沉降速度较低的粒径<0.1mm土粒百分含量成幂函数形式向上递增。此外,风蚀物平均粒径随高度变细且在50cm处细于0.1mm,因此,土壤颗粒 成为悬移物质而上升到50cm以上高度时可能搬运到较远的地区
[8] 哈斯. 2004.

腾格里沙漠东南缘沙丘表面风沙流结构变异的初步研究

[J]. 科学通报, 49(11): 1099-1104.

https://doi.org/10.3321/j.issn:0023-074X.2004.11.015      URL      Magsci      [本文引用: 4]      摘要

对腾格里沙漠东南缘沙丘表面各部位输沙量观测数据的分析结果发现,风力作用下的沙粒在沙丘表面上、下坡运动时,其输沙量垂线分布出现明显的变异.在距沙面 0~20 cm高度范围内,沙丘迎风坡各部位和丘顶输沙量垂线分布均符合单一指数递减规律;沙丘背风坡输沙量垂线分布出现两个不同的变化区间,多数以距沙面8~12 cm高度为界,下部输沙量随高度呈指数函数形式递减,上部为幂函数规律减少.在沙丘迎风坡,由于上坡运动沙粒跃移轨迹长度沿坡向上减小,随着风速和总输沙 量向丘顶方向增加,风沙流上层输沙量趋于相对减少;在背风坡,下坡运动的跃移沙粒起跳高度和轨迹长度增加使风沙流上层输沙量相对增加.

[Hasi E.2004.

Structural variations of sand-bearing airflow over dune at southeastern fringe of Tengger Desert

[J]. Chinese Science Bulletin, 49(11):1099-1104.]

https://doi.org/10.3321/j.issn:0023-074X.2004.11.015      URL      Magsci      [本文引用: 4]      摘要

对腾格里沙漠东南缘沙丘表面各部位输沙量观测数据的分析结果发现,风力作用下的沙粒在沙丘表面上、下坡运动时,其输沙量垂线分布出现明显的变异.在距沙面 0~20 cm高度范围内,沙丘迎风坡各部位和丘顶输沙量垂线分布均符合单一指数递减规律;沙丘背风坡输沙量垂线分布出现两个不同的变化区间,多数以距沙面8~12 cm高度为界,下部输沙量随高度呈指数函数形式递减,上部为幂函数规律减少.在沙丘迎风坡,由于上坡运动沙粒跃移轨迹长度沿坡向上减小,随着风速和总输沙 量向丘顶方向增加,风沙流上层输沙量趋于相对减少;在背风坡,下坡运动的跃移沙粒起跳高度和轨迹长度增加使风沙流上层输沙量相对增加.
[9] 韩致文, 缑倩倩, 杜鹤强, . 2012.

新月形沙丘表面100cm高度内风沙流输沙量垂直分布函数分段拟合

[J]. 地理科学, 32(7): 892-897.

URL      Magsci      [本文引用: 5]      摘要

为研究新月形沙丘表面不同层位风沙流输沙量的垂直分布函数,实测了塔克拉玛干沙漠腹地典型新月形沙丘表面100 cm高度内(以1 cm分隔)的输沙量。分段拟合分析表明:新月形沙丘迎风坡脚输沙量垂直分布规律不完全服从指数函数,出现与戈壁风沙流结构特征相似的"象鼻效应",在0~3 cm区间内输沙量逐渐增大,3cm以上输沙量随高度呈指数函数衰减;沙丘顶部0~10 cm区间输沙量随高度呈指数函数衰减,10 cm以上呈二次函数衰减;沙丘左翼端输沙量随高度呈幂函数分布,沙丘右翼端0~20 cm内以指数函数衰减,20 cm以上呈三次函数衰减;沙丘背风坡脚风沙流输沙量在0~60 cm和60 cm以上分别呈不同形式的三次函数分布。

[Han Z W, Gou Q Q, Du H Q, et al.2012.

The piecewise fitting of sand flux vertical distribution of wind-sand flow within 100-cm height above the Barchan Dune Surface

[J]. Scientia Geographica Sinica, 32(7): 892-897. ]

URL      Magsci      [本文引用: 5]      摘要

为研究新月形沙丘表面不同层位风沙流输沙量的垂直分布函数,实测了塔克拉玛干沙漠腹地典型新月形沙丘表面100 cm高度内(以1 cm分隔)的输沙量。分段拟合分析表明:新月形沙丘迎风坡脚输沙量垂直分布规律不完全服从指数函数,出现与戈壁风沙流结构特征相似的"象鼻效应",在0~3 cm区间内输沙量逐渐增大,3cm以上输沙量随高度呈指数函数衰减;沙丘顶部0~10 cm区间输沙量随高度呈指数函数衰减,10 cm以上呈二次函数衰减;沙丘左翼端输沙量随高度呈幂函数分布,沙丘右翼端0~20 cm内以指数函数衰减,20 cm以上呈三次函数衰减;沙丘背风坡脚风沙流输沙量在0~60 cm和60 cm以上分别呈不同形式的三次函数分布。
[10] 何京丽, 郭建英, 邢恩德, . 2012.

黄河乌兰布和沙漠段沿岸风沙流结构与沙丘移动规律

[J]. 农业工程学报, 28(17): 71-77.

https://doi.org/10.3969/j.issn.1002-6819.2012.17.011      URL      Magsci      [本文引用: 2]      摘要

为明确黄河乌兰布和沙漠段沿岸 的风沙活动及沙丘移动特征,该文以黄河乌兰布和沙漠段沿岸的流动沙丘为研究对象,采用野外观测与实验室分析相结合的方法对沿岸沙丘的起沙风况、沙物质组 成、风沙流结构及沙丘移动规律进行初步的定量研究。结果表明:起沙风的主风为西南—西风,集中于3-5月份,且5~6m/s风占起沙风的50.26%;沙 物质粒径以细砂(0.1~0.25mm)为主,沿黄段沙丘粒径极细砂以下(≤0.1mm)的沙物质粒径组成比沙漠腹地减少8.92%;距地60cm高度范 围内,81.75%的沙物质在0~10cm高的气层中通过。在沙丘的不同部位上,相对输沙量与高程之间有着良好的幂函数关系;沙丘向前移动的距离为 8.19m/a,主要发生在3-5月份。该研究结果可为合理计算入黄风积沙量及完善黄河沿岸综合防护体系提供科学依据。

[He J L, Guo J Y, Xing E D, et al.2012.

Structure of wind-sand flow and law of dune movement along bank of Yellow River in Ulan Buh desert

[J]. Transactions of the CSAE, 28(17): 71-77. ]

https://doi.org/10.3969/j.issn.1002-6819.2012.17.011      URL      Magsci      [本文引用: 2]      摘要

为明确黄河乌兰布和沙漠段沿岸 的风沙活动及沙丘移动特征,该文以黄河乌兰布和沙漠段沿岸的流动沙丘为研究对象,采用野外观测与实验室分析相结合的方法对沿岸沙丘的起沙风况、沙物质组 成、风沙流结构及沙丘移动规律进行初步的定量研究。结果表明:起沙风的主风为西南—西风,集中于3-5月份,且5~6m/s风占起沙风的50.26%;沙 物质粒径以细砂(0.1~0.25mm)为主,沿黄段沙丘粒径极细砂以下(≤0.1mm)的沙物质粒径组成比沙漠腹地减少8.92%;距地60cm高度范 围内,81.75%的沙物质在0~10cm高的气层中通过。在沙丘的不同部位上,相对输沙量与高程之间有着良好的幂函数关系;沙丘向前移动的距离为 8.19m/a,主要发生在3-5月份。该研究结果可为合理计算入黄风积沙量及完善黄河沿岸综合防护体系提供科学依据。
[11] 刘芳, 郝玉光, 辛智鸣, . 2014.

乌兰布和沙漠东北缘地表风沙流结构特征

[J]. 中国沙漠, 34(5): 1200-1207.

https://doi.org/10.7522/j.issn.1000-694X.2014.00096      URL      Magsci      [本文引用: 1]      摘要

在国家林业局磴口荒漠生态站长期监测的基础上,利用多种积沙仪,对乌兰布和沙漠东北缘流动沙丘、油蒿半固定沙丘、白刺半固定沙丘、油蒿固定沙丘、白刺固定沙丘5种典型下垫面近地面(0~100cm)的风沙流输沙量进行了实地观测和对比分析。结果表明:(1)输沙率(q)随高度(h)增加呈幂函数(q=ah-b,R2≥0.8409)规律衰减,随风速(v)增大呈幂函数(q=av b,R2≥0.9256)规律增加,42.8%~70.7%的输沙量分布在10cm高度内,67.6%~90.0%的输沙量分布于30cm高度内。当地表植被盖度达到40%以上时,输沙率下降至无植被覆盖地表输沙率的6.6%以下,可有效阻止地表风蚀。(2)沙物质主要由粒径为50~250μm的细沙和极细沙构成,各高度层风蚀物粒度组成服从单峰态分布,峰值在100~250μm。随高度增加,风蚀物粒径范围趋于变窄,粒径趋于更细。(3)起沙风多出现在WSW和NW方向,占全年起沙风的53.19%。风沙流中跃移输沙、蠕移输沙的空间分布在理论上应与风向频率分布基本一致,差异性主要由各方位风的强度和持续时间等因素导致。研究结果可为该区域防沙工程设计提供理论参考。

[Liu F, Hao Y G, Xin Z M, et al.2014.

The surface Aeolian-sand flow structure in the Northeastern margin of the Ulanbuh Desert

[J]. Journal of Desert Research, 34(5): 1200-1207. ]

https://doi.org/10.7522/j.issn.1000-694X.2014.00096      URL      Magsci      [本文引用: 1]      摘要

在国家林业局磴口荒漠生态站长期监测的基础上,利用多种积沙仪,对乌兰布和沙漠东北缘流动沙丘、油蒿半固定沙丘、白刺半固定沙丘、油蒿固定沙丘、白刺固定沙丘5种典型下垫面近地面(0~100cm)的风沙流输沙量进行了实地观测和对比分析。结果表明:(1)输沙率(q)随高度(h)增加呈幂函数(q=ah-b,R2≥0.8409)规律衰减,随风速(v)增大呈幂函数(q=av b,R2≥0.9256)规律增加,42.8%~70.7%的输沙量分布在10cm高度内,67.6%~90.0%的输沙量分布于30cm高度内。当地表植被盖度达到40%以上时,输沙率下降至无植被覆盖地表输沙率的6.6%以下,可有效阻止地表风蚀。(2)沙物质主要由粒径为50~250μm的细沙和极细沙构成,各高度层风蚀物粒度组成服从单峰态分布,峰值在100~250μm。随高度增加,风蚀物粒径范围趋于变窄,粒径趋于更细。(3)起沙风多出现在WSW和NW方向,占全年起沙风的53.19%。风沙流中跃移输沙、蠕移输沙的空间分布在理论上应与风向频率分布基本一致,差异性主要由各方位风的强度和持续时间等因素导致。研究结果可为该区域防沙工程设计提供理论参考。
[12] 刘树林, 王涛, 郭坚. 2006.

浑善达克沙地春季风沙活动特征观测研究

[J]. 中国沙漠, 26(3): 356-361.

https://doi.org/10.3321/j.issn:1000-694X.2006.03.007      URL      Magsci      [本文引用: 3]      摘要

通过野外实验观测和室内分析整 理的方法,对浑善达克沙地不同程度沙漠化土地的春季风沙活动特征进行了研究。结果表明:输沙率随风速增加成非线性增大;相同风速下,随着土地沙漠化程度的 增加,输沙率成指数式增加;春季由于植被高度有限,覆盖度小于10%与覆盖度大于25%的沙地,对风场的响应,表现出明显不同的风沙流结构;不同程度的沙 漠化土地上,发生风蚀搬运的物质组成也明显不同;研究区春季影响风沙活动的因素,主要是土地沙漠化程度,降水的迟早以及残存的灌木与多年生草本植物的多少 等。

[Liu S L, Wang T, Guo J.2006.

Characteristics of blown sand activities in Hunshandake sandy land in spring

[J]. Journal of Desert Research, 26(3): 356-361.]

https://doi.org/10.3321/j.issn:1000-694X.2006.03.007      URL      Magsci      [本文引用: 3]      摘要

通过野外实验观测和室内分析整 理的方法,对浑善达克沙地不同程度沙漠化土地的春季风沙活动特征进行了研究。结果表明:输沙率随风速增加成非线性增大;相同风速下,随着土地沙漠化程度的 增加,输沙率成指数式增加;春季由于植被高度有限,覆盖度小于10%与覆盖度大于25%的沙地,对风场的响应,表现出明显不同的风沙流结构;不同程度的沙 漠化土地上,发生风蚀搬运的物质组成也明显不同;研究区春季影响风沙活动的因素,主要是土地沙漠化程度,降水的迟早以及残存的灌木与多年生草本植物的多少 等。
[13] 牛艳频. 2011.

河北坝上农田风沙流结构特征研究: 以康保县为例[D]

. 石家庄: 河北师范大学.

[本文引用: 1]     

[Niu Y P. 2011.

A study on the characteristics of sand flow structure in farmland of Bashang, Hebei Province: taking Kang Bao County for example

[D]. Shijiazhuang, China: Hebei Normal University. ]

[本文引用: 1]     

[14] 屈建军, 黄宁, 拓万全, . 2005.

戈壁风沙流结构特性及其意义

[J]. 地球科学进展, 20(1): 19-23.

https://doi.org/10.3321/j.issn:1001-8166.2005.01.005      URL      Magsci      [本文引用: 2]      摘要

通过砾质戈壁风沙流野外实测数 据的分析以及风洞模拟实验研究发现:戈壁风沙流结构具有与沙漠风沙流完全不同的风沙流特征,戈壁风沙地表的粗糙度随风速的增大而增加,其表面风沙流输沙量 高度分布表现出独特的"象鼻"效应,在一定高度处呈现最大值,并随风速的增加而增高。该"象鼻"效应导致戈壁风沙流结构特征值λ远大于1,不论风速多大, 风沙流都处于未饱和状态的非堆积搬运状态。这种特殊性质比较清楚地解释了敦煌莫高窟千年来不被沙山埋没的谜底。并且在风沙防治工程实践中,采用砾石压沙措 施,构造类似与砾质戈壁的下垫面,人工促使风沙流结构呈现"象鼻"形状,可使防沙工程达到理想的输导作用。

[Qu J J, Huang N, Ta W Q, et al.2005.

Structural characteristics of Gobi sand-drift and its significance

[J]. Advances in Earth Science, 20(1): 19-23. ]

https://doi.org/10.3321/j.issn:1001-8166.2005.01.005      URL      Magsci      [本文引用: 2]      摘要

通过砾质戈壁风沙流野外实测数 据的分析以及风洞模拟实验研究发现:戈壁风沙流结构具有与沙漠风沙流完全不同的风沙流特征,戈壁风沙地表的粗糙度随风速的增大而增加,其表面风沙流输沙量 高度分布表现出独特的"象鼻"效应,在一定高度处呈现最大值,并随风速的增加而增高。该"象鼻"效应导致戈壁风沙流结构特征值λ远大于1,不论风速多大, 风沙流都处于未饱和状态的非堆积搬运状态。这种特殊性质比较清楚地解释了敦煌莫高窟千年来不被沙山埋没的谜底。并且在风沙防治工程实践中,采用砾石压沙措 施,构造类似与砾质戈壁的下垫面,人工促使风沙流结构呈现"象鼻"形状,可使防沙工程达到理想的输导作用。
[15] 王洪涛, 董治宝, 张晓航. 2004.

风沙流中沙粒浓度分布的实验研究

[J]. 地球科学进展, 19(5): 732-735.

https://doi.org/10.3321/j.issn:1001-8166.2004.05.007      URL      Magsci      [本文引用: 1]      摘要

利用粒子图像测速技术(PIV),在风洞内对与天然沙接近的石英 沙风沙流沙颗粒浓度沿高度分布进行了研究.对3种不同轴线风速研究结果表明,风沙流中沙粒浓度沿水平方向基本不变,而随高度呈指数衰减,而且其衰减速率与 风速密切相关.风速越大,衰减速率越慢;风速越小,衰减速率越快.风沙运动一旦发生时,靠近沙床表面的沙粒浓度随风速变化很小,可以认为趋于稳定,达到最 大值.

[Wang H T, Dong Z B, Zhang X H.2004.

A study of the particle concentration in the sand flux-a wind tunnel investigation

[J]. Advances in Earth Science, 19(5): 732-735.]

https://doi.org/10.3321/j.issn:1001-8166.2004.05.007      URL      Magsci      [本文引用: 1]      摘要

利用粒子图像测速技术(PIV),在风洞内对与天然沙接近的石英 沙风沙流沙颗粒浓度沿高度分布进行了研究.对3种不同轴线风速研究结果表明,风沙流中沙粒浓度沿水平方向基本不变,而随高度呈指数衰减,而且其衰减速率与 风速密切相关.风速越大,衰减速率越慢;风速越小,衰减速率越快.风沙运动一旦发生时,靠近沙床表面的沙粒浓度随风速变化很小,可以认为趋于稳定,达到最 大值.
[16] 王仁德, 邹学勇, 吴晓旭, . 2009.

半湿润区农田风蚀物垂直分布特征

[J]. 水土保持学报, 23(5): 39-43.

URL      [本文引用: 1]      摘要

通过两种观测手段对半湿润区农田风蚀物垂直分布特征进行了研究。结果表明,半湿润区农田风蚀强度较弱,风蚀物颗粒较细,主要由极细沙和粉沙组成。风蚀物含量垂向分布遵循幂函数递减规律,反映了以悬移质为主的风沙流结构特征。农田地表特征、风速和粒级等因素均对风沙流结构具有显著影响。农田风蚀强度大小影响风蚀物在近地表的分布规律。风速增大使相对输沙量在近地表增加,上层减少。风蚀物粒级越大,则输沙量沿垂直方向递减的幅度愈大。随着高度增加,风蚀物各粒级含量中砂级组分含量减少,粉砂及粘土组分含量增加,风蚀物粒径变细,粒径范围不断收窄。最大粒径和平均粒径沿垂直方向的变化都服从指数函数递减规律。

[Wang R D, Zou X Y, Wu X X, et al.2009.

The vertical distribution characteristics of farmland wind-erosion dust over semi-humid region

[J]. Journal of Soil and Water Conservation, 23(5): 39-43. ]

URL      [本文引用: 1]      摘要

通过两种观测手段对半湿润区农田风蚀物垂直分布特征进行了研究。结果表明,半湿润区农田风蚀强度较弱,风蚀物颗粒较细,主要由极细沙和粉沙组成。风蚀物含量垂向分布遵循幂函数递减规律,反映了以悬移质为主的风沙流结构特征。农田地表特征、风速和粒级等因素均对风沙流结构具有显著影响。农田风蚀强度大小影响风蚀物在近地表的分布规律。风速增大使相对输沙量在近地表增加,上层减少。风蚀物粒级越大,则输沙量沿垂直方向递减的幅度愈大。随着高度增加,风蚀物各粒级含量中砂级组分含量减少,粉砂及粘土组分含量增加,风蚀物粒径变细,粒径范围不断收窄。最大粒径和平均粒径沿垂直方向的变化都服从指数函数递减规律。
[17] 王训明, 董治宝, 陈广庭. 2001.

塔克拉玛干沙漠中部部分地区风沙环境特征

[J]. 中国沙漠, 21(1): 56-61.

https://doi.org/10.3321/j.issn:1000-694X.2001.01.011      URL      Magsci      [本文引用: 1]      摘要

通过对塔克拉玛干沙漠中部部分 地区的气象资料分析、野外实地风沙观测和理论计算 ,对其风沙环境特征作出了一些初步分析。结果表明 :沙漠边缘地区年起沙风时间数在 2 70× 10 4 min左右 ,输沙总量为 3 80 0kg·m-1·a-1,年输沙总量与合成输沙总量的比值在 1 83~ 2 39之间变化。而沙漠腹地塔中地区年起沙风时间数在 4 6 1× 10 4 min以上 ,输沙总量为 6 10 0kg m-1 a-1,最大输沙量为 80 0 0kg·m-1·a-1。年总输沙量与合成输沙量的比值在 1 38~ 2 12之间变化。此外 ,其沙丘形态与Tomas( 1991)所阐述的沙丘发育格

[Wang X M, Dong Z B, Chen G T.2001.

Characteristics of blown sand environment in Middle Taklimakan Desert

[J]. Journal of Desert Research, 21(1): 56-61.]

https://doi.org/10.3321/j.issn:1000-694X.2001.01.011      URL      Magsci      [本文引用: 1]      摘要

通过对塔克拉玛干沙漠中部部分 地区的气象资料分析、野外实地风沙观测和理论计算 ,对其风沙环境特征作出了一些初步分析。结果表明 :沙漠边缘地区年起沙风时间数在 2 70× 10 4 min左右 ,输沙总量为 3 80 0kg·m-1·a-1,年输沙总量与合成输沙总量的比值在 1 83~ 2 39之间变化。而沙漠腹地塔中地区年起沙风时间数在 4 6 1× 10 4 min以上 ,输沙总量为 6 10 0kg m-1 a-1,最大输沙量为 80 0 0kg·m-1·a-1。年总输沙量与合成输沙量的比值在 1 38~ 2 12之间变化。此外 ,其沙丘形态与Tomas( 1991)所阐述的沙丘发育格
[18] 吴霞, 哈斯, 杜会石, . 2012.

库布齐沙漠南缘抛物线形沙丘表面粒度特征

[J]. 沉积学报, 30(5): 937-944.

URL      Magsci      [本文引用: 4]      摘要

对库布齐沙漠南缘抛物线形沙丘 特征断面上下层(0~5cm、5~10cm)沉积物采样分析结果表明,沙丘粒径与分选参数及其分布随沙丘形态、发育程度和植被生长状况发生变化。抛物线形 沙丘丘体迎风坡下凹背风坡上凸,丘顶始终处于侵蚀亚环境。在顺风向断面,平均粒径从迎风坡脚到丘顶变粗,从丘顶到背风坡脚又变细,且这种变化在高大沙丘上 更为明显;分选性在迎风坡为中等和较好,丘顶较差,顺风向到背风坡脚逐渐由中等变为较好;粒径频率曲线在丘顶双峰正偏,除迎风坡脚单峰正偏外,其余部位均 单峰近对称。在垂直于风向的两翼断面,平均粒径在成熟沙丘由翼顶向两侧坡脚趋于变细,而在欠成熟沙丘无明显的变化趋势。翼间平地沉积物受植被等影响,平均 粒径偏细但分选性差,偏度为正偏和极正偏,峰度为尖锐和非常尖锐。受不同时期风况的影响,成熟抛物线形沙丘上下层粒度参数在沙丘断面的分布较欠成熟沙丘一 致。

[Wu X, Hasi E, Du H S, et al.2012,

Grain size distribution of parabolic dunes on the Southern fringe of Hobq Desert

[J]. Acta Sedimentologica Sinica, 30(5): 937-944. ]

URL      Magsci      [本文引用: 4]      摘要

对库布齐沙漠南缘抛物线形沙丘 特征断面上下层(0~5cm、5~10cm)沉积物采样分析结果表明,沙丘粒径与分选参数及其分布随沙丘形态、发育程度和植被生长状况发生变化。抛物线形 沙丘丘体迎风坡下凹背风坡上凸,丘顶始终处于侵蚀亚环境。在顺风向断面,平均粒径从迎风坡脚到丘顶变粗,从丘顶到背风坡脚又变细,且这种变化在高大沙丘上 更为明显;分选性在迎风坡为中等和较好,丘顶较差,顺风向到背风坡脚逐渐由中等变为较好;粒径频率曲线在丘顶双峰正偏,除迎风坡脚单峰正偏外,其余部位均 单峰近对称。在垂直于风向的两翼断面,平均粒径在成熟沙丘由翼顶向两侧坡脚趋于变细,而在欠成熟沙丘无明显的变化趋势。翼间平地沉积物受植被等影响,平均 粒径偏细但分选性差,偏度为正偏和极正偏,峰度为尖锐和非常尖锐。受不同时期风况的影响,成熟抛物线形沙丘上下层粒度参数在沙丘断面的分布较欠成熟沙丘一 致。
[19] 吴晓旭, 邹学勇, 王仁德, . 2011.

毛乌素沙地不同下垫面的风沙运动特征

[J]. 中国沙漠, 31(4): 828-835.

URL      Magsci      [本文引用: 1]      摘要

基于野外实地观测,研究了毛乌素沙地不同下垫面的风沙运动特征. 平坦流沙地上的风速随高度呈对数分布;沙丘上的风速梯度在高度上的变化随植被盖度增大而增强;相近风速下,0~60 cm高度范围内的输沙强度从大到小依次为流动沙丘丘顶>平坦流沙地>半流动沙丘丘顶>裸露黄土梁地>黄土梁翻耕地>玉米留茬地>半固定沙丘丘顶.同一植被 盖度下,沙丘顶部输沙率随风速增加而增大,粗糙度随风速增加而减小.当风速小于起沙风速时,粗糙度随植被盖度的增加而增大;当风速大于起沙风速时,平坦流 沙地和沙丘顶部的粗糙度随风速增大有增加趋势,产生这种现象的可能原因是跃移层沙物质对气流的阻力随风速增大而增大.根据各类沙源地的起沙强度和总面积, 风沙灾害防治的重点是植被盖度较小的沙地和黄土梁地.

[Wu X X, Zou X Y, Wang R D, et al.2011.

Aeolian movement characteristics over different underlying surfaces in Mu Us Sandy Land

[J]. Journal of Desert Research, 31(4): 828-835. ]

URL      Magsci      [本文引用: 1]      摘要

基于野外实地观测,研究了毛乌素沙地不同下垫面的风沙运动特征. 平坦流沙地上的风速随高度呈对数分布;沙丘上的风速梯度在高度上的变化随植被盖度增大而增强;相近风速下,0~60 cm高度范围内的输沙强度从大到小依次为流动沙丘丘顶>平坦流沙地>半流动沙丘丘顶>裸露黄土梁地>黄土梁翻耕地>玉米留茬地>半固定沙丘丘顶.同一植被 盖度下,沙丘顶部输沙率随风速增加而增大,粗糙度随风速增加而减小.当风速小于起沙风速时,粗糙度随植被盖度的增加而增大;当风速大于起沙风速时,平坦流 沙地和沙丘顶部的粗糙度随风速增大有增加趋势,产生这种现象的可能原因是跃移层沙物质对气流的阻力随风速增大而增大.根据各类沙源地的起沙强度和总面积, 风沙灾害防治的重点是植被盖度较小的沙地和黄土梁地.
[20] 吴正, . 2010. 风沙地貌与治沙工程学[M]. 北京: 科学出版社.

[本文引用: 2]     

[Wu Z, et al. 2010. Geomorphology of wind-drift sands and their controlled engineering[M]. Beijing, China: Science Press. ]

[本文引用: 2]     

[21] 杨兴华, 何清, 阿吉古丽·沙依提, . 2012.

塔克拉玛干沙漠北缘荒漠过渡带风沙流结构特征分析

[J]. 干旱区研究, 29(4): 699-704.

URL      Magsci      [本文引用: 1]      摘要

利用多种集沙仪,通过野外实时 输沙观测,对塔克拉玛干沙漠北缘荒漠过渡带的地表风沙流特征进行了分析,结果表明:①100 cm高度范围内,总输沙量的47.3%分布在30 cm高度内,这一比例小于前人的研究结果;输沙量随高度的变化比较符合幂函数分布。②风沙流输沙的粒径以细砂、极细砂与粉砂为主,各高度层所占比例均达 99%以上;风沙流输沙平均粒径随高度增加而减小,沙尘的含量随高度增加呈现"象鼻"状分布。③风沙流中贴地层风速廓线受风沙相互作用的影响,不再符合对 数分布,更加符合幂函数u=azb分布。

[Yang X H, He Q, Ajiguli S, et al.2012.

Study on structure of wind-blown sand flow over the desert ecotone in the Northern marginal zone of the Taklimakan desert

[J]. Arid Zone Research, 29(4): 699-704. ]

URL      Magsci      [本文引用: 1]      摘要

利用多种集沙仪,通过野外实时 输沙观测,对塔克拉玛干沙漠北缘荒漠过渡带的地表风沙流特征进行了分析,结果表明:①100 cm高度范围内,总输沙量的47.3%分布在30 cm高度内,这一比例小于前人的研究结果;输沙量随高度的变化比较符合幂函数分布。②风沙流输沙的粒径以细砂、极细砂与粉砂为主,各高度层所占比例均达 99%以上;风沙流输沙平均粒径随高度增加而减小,沙尘的含量随高度增加呈现"象鼻"状分布。③风沙流中贴地层风速廓线受风沙相互作用的影响,不再符合对 数分布,更加符合幂函数u=azb分布。
[22] 尹永顺. 1989.

砾漠大风地区风沙流研究

[J]. 中国沙漠, 9(4): 30-39.

URL      [本文引用: 1]      摘要

1985年开始连续三年,在新疆吐(鲁番)—鱼(儿沟)段,用自制的集沙仪对多次大风进行了风速与集沙量关系的观测,得到的经验公式为: Q1=1.92e~0.31(V—u) 此式与附近气象站风速资料推算之全年输沙量值极为接近。

[Yin Y S.1989.

Study on sand drift in strong wind region in Gravel Desert

[J]. Journal of Desert Research, 9(4): 30-39. ]

URL      [本文引用: 1]      摘要

1985年开始连续三年,在新疆吐(鲁番)—鱼(儿沟)段,用自制的集沙仪对多次大风进行了风速与集沙量关系的观测,得到的经验公式为: Q1=1.92e~0.31(V—u) 此式与附近气象站风速资料推算之全年输沙量值极为接近。
[23] 张广, 武俊瑛, 惠彦君, . 2006.

浑善达克沙地公路综合防护技术及其效益分析

[J]. 干旱区资源与环境, 20(5): 189-196.

https://doi.org/10.3969/j.issn.1003-7578.2006.05.037      URL      [本文引用: 1]      摘要

浑善达克沙地省际通道综合防护体系包括:公路沙害快速治理和沙源 控制技术及耐风沙植被建植技术.阻沙带、固沙带改变了风沙流结构,降低了输沙强度,增加了地表粗糙度,有效的起到了削弱风速,阻截流沙,控制沙丘前移,保 持地表稳定的作用;建立稳定的耐风沙植被是持久固沙和生物防护的核心;首次大规模使用"固沙网"专利技术产品用于公路快速固沙保苗,实践证明采用固沙网与 柳条立式沙障的组合固沙技术对于快速固沙和植被恢复的作用更加显著;并提出了公路沙害快速治理技术体系与配套的技术措施.项目实施过程中3年投入产出比为 1∶2.6,通过公路沙害治理工程的实施,稳定防护10年的经济总收益为4.67亿元;如将挖方路堑段砂质陡坡用植物固沙措施代替传统石砌护面墙技术推广 至其它工程,效益更为显著.该项目技术研究与工程建设紧密结合,操作性强,能快速有效治理荒漠化地区公路沙害,总结出了沙区公路、铁路沙害的治理模式,对 于我国荒漠化治理有推广应用价值.

[Zhang G, Wu J Y, Hui Y J, et al.2006.

Benefit analysis and integrated preservation technology system of the shelter belt of highway in Otindag Sandy Land

[J]. Journal of Arid Land Resources and Environment, 20(5): 189-196. ]

https://doi.org/10.3969/j.issn.1003-7578.2006.05.037      URL      [本文引用: 1]      摘要

浑善达克沙地省际通道综合防护体系包括:公路沙害快速治理和沙源 控制技术及耐风沙植被建植技术.阻沙带、固沙带改变了风沙流结构,降低了输沙强度,增加了地表粗糙度,有效的起到了削弱风速,阻截流沙,控制沙丘前移,保 持地表稳定的作用;建立稳定的耐风沙植被是持久固沙和生物防护的核心;首次大规模使用"固沙网"专利技术产品用于公路快速固沙保苗,实践证明采用固沙网与 柳条立式沙障的组合固沙技术对于快速固沙和植被恢复的作用更加显著;并提出了公路沙害快速治理技术体系与配套的技术措施.项目实施过程中3年投入产出比为 1∶2.6,通过公路沙害治理工程的实施,稳定防护10年的经济总收益为4.67亿元;如将挖方路堑段砂质陡坡用植物固沙措施代替传统石砌护面墙技术推广 至其它工程,效益更为显著.该项目技术研究与工程建设紧密结合,操作性强,能快速有效治理荒漠化地区公路沙害,总结出了沙区公路、铁路沙害的治理模式,对 于我国荒漠化治理有推广应用价值.
[24] 张华, 李锋瑞, 张铜会, . 2002.

科尔沁沙地不同下垫面风沙流结构与变异特征

[J]. 水土保持学报, 16(2): 20-23, 28.

https://doi.org/10.3321/j.issn:1009-2242.2002.02.006      URL      [本文引用: 1]      摘要

对流动、半流动、半固定和固定 沙地 4种不同下垫面 0~ 2 0 cm气流层的风沙流结构与变异特征研究表明 :(1 )不同退化沙地在总输沙量及各层输沙量上存在明显的差异 ,在 5月 1 5日的测定中 ,流动沙地的总输沙量是 83 .1g/ cm2 .h,分别是半流动、半固定和固定沙地的 2 .1倍、9.2倍和 33 .9倍 ;而在 5月 1 5日的测定中 ,流动沙地的总输沙量 1 0 5.7g/ cm2 .h,分别是半流动、半固定和固定沙地的 5.6倍、1 4.1倍和 75.6倍。(2 )总输沙量的 60以上分布在 1 0cm的高度内 ,随高度的增加 ,输沙量呈负指数函数下降。(3)风蚀物中粗粒

[Zhang H, Li F R, Zhang T H, et al.2002.

Wind-Sand flow structure and its variation under different surface conditions in Korqin sandy land

[J]. Journal of Soil and Water Conservation, 16(2): 20-23, 28. ]

https://doi.org/10.3321/j.issn:1009-2242.2002.02.006      URL      [本文引用: 1]      摘要

对流动、半流动、半固定和固定 沙地 4种不同下垫面 0~ 2 0 cm气流层的风沙流结构与变异特征研究表明 :(1 )不同退化沙地在总输沙量及各层输沙量上存在明显的差异 ,在 5月 1 5日的测定中 ,流动沙地的总输沙量是 83 .1g/ cm2 .h,分别是半流动、半固定和固定沙地的 2 .1倍、9.2倍和 33 .9倍 ;而在 5月 1 5日的测定中 ,流动沙地的总输沙量 1 0 5.7g/ cm2 .h,分别是半流动、半固定和固定沙地的 5.6倍、1 4.1倍和 75.6倍。(2 )总输沙量的 60以上分布在 1 0cm的高度内 ,随高度的增加 ,输沙量呈负指数函数下降。(3)风蚀物中粗粒
[25] 张克存, 屈建军, 俎瑞平, . 2005.

戈壁风沙流结构和风速廓线特征研究

[J]. 水土保持研究, 12(1): 54-55, 58.

https://doi.org/10.3969/j.issn.1005-3409.2005.01.016      URL      Magsci      [本文引用: 2]      摘要

通过对戈壁地表风沙流特性的风洞模拟实验,旨在探讨戈壁地表性质是如何影响气流的紊动性,并对风沙流的结构和风沙活动层内的风速廓线产生影响,从而对野外 风沙工程的设计提供理论依据.实验发现:在戈壁地表风沙活动层主要集中在距地表20 cm范围内;由于沙颗粒与戈壁地表的砾石发生碰撞,浓度分布不再简单的服从对数关系递减,其极值出现的高度随风速的增加而上移,呈现"象鼻效应";不同风 速下风沙活动层内同一高度含沙颗粒浓度之间存在很好的相关性.

[Zhang K C, Qu J J, Zu R P, et al.2005.

Research on the characteristics of structure of drifting sand flux and wind velocity profile over Gobi

[J]. Research of Soil and Water Conservation, 12(1): 54-55, 58. ]

https://doi.org/10.3969/j.issn.1005-3409.2005.01.016      URL      Magsci      [本文引用: 2]      摘要

通过对戈壁地表风沙流特性的风洞模拟实验,旨在探讨戈壁地表性质是如何影响气流的紊动性,并对风沙流的结构和风沙活动层内的风速廓线产生影响,从而对野外 风沙工程的设计提供理论依据.实验发现:在戈壁地表风沙活动层主要集中在距地表20 cm范围内;由于沙颗粒与戈壁地表的砾石发生碰撞,浓度分布不再简单的服从对数关系递减,其极值出现的高度随风速的增加而上移,呈现"象鼻效应";不同风 速下风沙活动层内同一高度含沙颗粒浓度之间存在很好的相关性.
[26] 张伟民, 汪万福, 张克存, . 2009.

不同沙源供给条件下砾石床面的风沙流结构与蚀积量变化风洞实验研究

[J]. 中国沙漠, 29(6): 1015-1020.

URL      Magsci      [本文引用: 1]      摘要

通过对不同沙源供给条件下各种砾石床面的风沙流结构、床面风蚀及 堆积沙量变化的风洞实验,结果表明,风沙流结构是判断戈壁风沙流饱和与不饱和的一个重要途径,不同的戈壁风沙流结构对床面输、阻沙特性具有不同的指示意 义.近地表0~6 cm高度内的风沙流结构决定了床面的输、阻性质,而6 cm以上的风沙流结构反映了风力对沙物质的输送状况.沙源供给的丰富与否,决定了风沙流的饱和程度,以及风沙流在砾石床面产生的蚀积状况.同等风速条件 下,饱和风沙流的输沙率是非饱和风沙流输沙率的2~8倍.在饱和风沙流情形下,床面过程总体以积沙为主,且随风力的增强,床面积沙量急剧增加.在不饱和风 沙流情形下,砾石床面总体以风蚀和输送沙物质过程为主,风沙流结构在0~2 cm高度内反映出砾石床面具有明显的阻沙功能,在2~5 cm高度上出现最大输沙值.

[Zhang W M, Wang W F, Zhang K C, et al.2009.

Wind tunnel experiments on sand-laden wind structure and sand erosion-deposit budget over Gravel bed under abundant and deficient sand supplies

[J]. Journal of Desert Research, 29(6): 1015-1020.]

URL      Magsci      [本文引用: 1]      摘要

通过对不同沙源供给条件下各种砾石床面的风沙流结构、床面风蚀及 堆积沙量变化的风洞实验,结果表明,风沙流结构是判断戈壁风沙流饱和与不饱和的一个重要途径,不同的戈壁风沙流结构对床面输、阻沙特性具有不同的指示意 义.近地表0~6 cm高度内的风沙流结构决定了床面的输、阻性质,而6 cm以上的风沙流结构反映了风力对沙物质的输送状况.沙源供给的丰富与否,决定了风沙流的饱和程度,以及风沙流在砾石床面产生的蚀积状况.同等风速条件 下,饱和风沙流的输沙率是非饱和风沙流输沙率的2~8倍.在饱和风沙流情形下,床面过程总体以积沙为主,且随风力的增强,床面积沙量急剧增加.在不饱和风 沙流情形下,砾石床面总体以风蚀和输送沙物质过程为主,风沙流结构在0~2 cm高度内反映出砾石床面具有明显的阻沙功能,在2~5 cm高度上出现最大输沙值.
[27] 张正偲, 董治宝. 2013.

腾格里沙漠东南部野外风沙流观测

[J]. 中国沙漠, 33(4): 973-980.

https://doi.org/10.7522/j.issn.1000-694X.2013.00089      URL      Magsci      [本文引用: 2]      摘要

风沙流是一种沙粒的群体运动,是风沙物理研究的重要内容之一.开 展风沙流研究,能够为风沙运动理论与工程实践提供理论支持.由于自然界风的阵性、地表湿度、下垫面属性和风程长度等影响因子的时空变化对风沙流运动的影 响,以及长期野外观测的限制,对风沙流的研究目前还不是很完善.本文依据中国科学院风沙科学观测场2005-2009年的长期观测资料,采用赤池信息量准 则(Akaike information criterion),对5种风沙流通量研究常用的拟合模型进行对比分析.结果表明,指数函数模型(q(z) =ae-z/b)是平坦沙地上风沙流的最佳表示方式,该模型拟合系数a值在0~600之间,但主要分布在0~100之间,占64.40%,其次为 100~150之间,占18.24%;系数b值在0~0.06之间,主要分布在0.015~0.040之间,占91.21%,其中0.025~0.030 占26.37%,其次为0.030~0.035,占24.40%.风沙流中的沙粒平均跃移高度与拟合系数b相同.风沙流在运动过程中,主要在高度20 cm以下传输.风沙流对地表的风蚀和堆积机率几乎是相等的.

[Zhang Z C, Dong Z B.2013.

Field observation of Aeolian sediment flux in the southeast Tengger Desert

[J]. Journal of Desert Research, 33(4): 973-980. ]

https://doi.org/10.7522/j.issn.1000-694X.2013.00089      URL      Magsci      [本文引用: 2]      摘要

风沙流是一种沙粒的群体运动,是风沙物理研究的重要内容之一.开 展风沙流研究,能够为风沙运动理论与工程实践提供理论支持.由于自然界风的阵性、地表湿度、下垫面属性和风程长度等影响因子的时空变化对风沙流运动的影 响,以及长期野外观测的限制,对风沙流的研究目前还不是很完善.本文依据中国科学院风沙科学观测场2005-2009年的长期观测资料,采用赤池信息量准 则(Akaike information criterion),对5种风沙流通量研究常用的拟合模型进行对比分析.结果表明,指数函数模型(q(z) =ae-z/b)是平坦沙地上风沙流的最佳表示方式,该模型拟合系数a值在0~600之间,但主要分布在0~100之间,占64.40%,其次为 100~150之间,占18.24%;系数b值在0~0.06之间,主要分布在0.015~0.040之间,占91.21%,其中0.025~0.030 占26.37%,其次为0.030~0.035,占24.40%.风沙流中的沙粒平均跃移高度与拟合系数b相同.风沙流在运动过程中,主要在高度20 cm以下传输.风沙流对地表的风蚀和堆积机率几乎是相等的.
[28] 邹学勇, 董光荣, 王周龙. 1995.

戈壁风沙流若干特征研究

[J]. 中国沙漠, 15(4): 368-373.

URL      Magsci      [本文引用: 1]      摘要

本文从理论推导入手,阐述了戈壁风沙流中沙粒起跃角度、跃移高度和风沙流结构、强度、能量分布状况等特征,指出与流沙地表风沙流的显著差异,并得到风洞实验验证。

[Zou X Y, Dong G R, Wang Z L.1995.

A study on some characteristics of drifting sand flux over Gobi

[J]. Journal of Desert Research, 15(4): 368-373. ]

URL      Magsci      [本文引用: 1]      摘要

本文从理论推导入手,阐述了戈壁风沙流中沙粒起跃角度、跃移高度和风沙流结构、强度、能量分布状况等特征,指出与流沙地表风沙流的显著差异,并得到风洞实验验证。
[29] Anderson R S, Haff P K.1988.

Simulation of eolian saltation

[J]. Science, 241: 820-823.

https://doi.org/10.1126/science.241.4867.820      URL      PMID: 17829176      [本文引用: 1]      摘要

Saltation is important in the transport of sand-sized granular material by wind and in the ejection of dust from the bed both on Earth and on Mars. The evolution of the saltating population and all its characteristic profiles is calculated from inception by pure aerodynamic entrainment through to steady state. Results of numerical simulations of single-grain impacts into granular beds are condensed into analytic expressions for the number and speeds of grains rebounding or rejected (splashed) from the bed. A model is combined with (i) this numerical representation, (ii) an expression for the aerodynamic entrainment rate, and (iii) the modification of the wind velocity profile by saltating grains. Calculated steady state mass fluxes are within the range of mass fluxes measured in wind tunnel experiments; mass flux is nonlinearly dependent on the shear velocity. Aerodynamically entrained grains in the system are primarily seeding agents; at steady state, aerodynamic entrainment is rare. The time for the entire system to reach steady state is roughly 1 second, or several long-trajectory hop times.
[30] Baas A C W.2008.

Challenges in aeolian geomorphology: investigating Aeolian streamers

[J]. Geomorphology, 93(1-2): 3-16.

https://doi.org/10.1016/j.geomorph.2006.12.015      URL      [本文引用: 1]      摘要

ABSTRACT This paper reviews the challenges involved with instrumentation, data acquisition, analysis, and the application of theory when conducting field experiments in natural aeolian environments. This is presented in the context of a field investigation into the formation and behaviour of aeolian sand streamers. Also known as sand snakes, streamers are a familiar manifestation of pronounced spatial and temporal variability in wind-blown sand over beaches, dunes, and other sedimentary surfaces. Streamers represent complex and dynamic transport patterns that change over temporal scales on the order of 0.1 s and over a range of spatial scales from 0.1 to 10 m. These transport features are likely governed by near-surface turbulent structures in the wind, necessitating detailed measurements of turbulence dynamics in association with sediment transport patterns. This paper reviews all stages of the investigation, from field site selection to the evaluation of theoretical models. The discussion covers a range of topics, including: research strategy, site selection, instrumentation requirements and limitations, experimental design and measurement techniques, scale and precision of data acquisition, data processing and visualization, description and parameterisation of results, challenges of spatio-temporal data analysis, turbulence measurements in the saltation layer, scaling issues and non-dimensionalisations in fluid dynamics theory, and the application of theory and conceptual models to the complexities of real natural environments.The challenges discussed here apply to many geomorphological field investigations in general, and three principal issues are identified: 1) the need for inexpensive, compact, and robust instruments with high spatio-temporal resolution, 2) the lack of extended quantitative methods for the computational analysis of shapes, forms and patterns, and 3) the conceptual discrepancies and ambiguities of applying scaling parameters from experimental engineering and idealized theoretical models to complex natural geomorphic systems.
[31] Baas A C W, Sherman D J.2005.

Formation and behavior of aeolian streamers

[J]. Journal of Geophysical Research: Earth Surface (2003-2012), 110(F3): F03011.

https://doi.org/10.1029/2004JF000270      URL      [本文引用: 1]      摘要

[1] Field experiments were conducted to determine the characteristic spatial and temporal dimensions and behavior of aeolian streamers and to identify the processes responsible for their formation. An instrument array that included anemometer towers, pi毛zo-electric transport sensors (Safires), and hot-film probes was deployed to measure streamers and airflow dynamics on both a coastal dune and a desert sand mound in California. Aeolian transport occurs predominantly in the form of families of intertwining and bifurcating streamers, while under intense wind forcing, more complex patterns of nested streamers and clouds with embedded streamers develop. The streamers display a characteristic width of approximately 0.2 m and an average lateral spacing of about 1 m. These dimensions appear to be independent of mean airflow characteristics. The observations and measurements of streamers under different environmental conditions suggest that bed surface control in the form of differentiation in moisture content, grain size, or microtopography is not a necessary condition for the formation of streamers. The results show little correlation between possible streamwise vortices or burst sweep events and streamers. It is proposed that streamers are generated by near-surface gusts that originate from large eddies propagating to the ground from higher regions of the boundary layer. These elongated and stretched eddies scrape across the surface and initiate saltation along their path. This concept accounts for the characteristic size and spacing of streamers, their rapid propagation, and the fast response of saltation to wind speed fluctuations.
[32] Butterfield G R.1999.

Near-bed mass flux profiles in Aeolian sand transport: high-resolution measurements in a wind tunnel

[J]. Earth Surface Processes and Landforms, 24(5): 393-412.

https://doi.org/10.1002/(SICI)1096-9837(199905)24:5<393::AID-ESP996>3.0.CO;2-G      URL      [本文引用: 3]      摘要

Abstract Vertical profiles of the streamwise mass flux of blown sand in the near-bed (< 1761mm) region are analysed from high-resolution measurements made using an optical sensor in a wind tunnel. This analysis is complemented by detailed measurements of mass flux and mean velocity profiles throughout the boundary layer depth (0·1761m) using passive, chambered sand traps of small dimensions and armoured thermal anemometers, respectively. The data permit a preliminary analysis of the relations between the observed forms of the profiles of near-bed fluid stress and horizontal mass flux within a carefully conditioned boundary layer. Profiles of mass flux density are found to be characterized by three regions of differing gradient with transitions at about 261mm and 1961mm above the bed. The exponential decay of mass flux with height is confirmed for elevations above 1961mm, and when plotted as a function of u * 2 / g (a parameter of mean vertical trajectory height in saltation), the gradient of mass flux in this region scales with the wake-corrected friction velocity ( u ), where u 61>610·3061m s 611 . A separate near-bed region of more intense transport below 1961mm is identified which carries 80 per cent of the total mass flux. This region is evident in some previous field and wind tunnel data but not in profiles simulated by numerical models. Ventilated passive sand traps underestimate mass flux in this region by 37 per cent. At slow or moderate wind speeds a third significant region below 261mm is observed. These regions are likely to be related to grain populations in successive saltation, low-energy ejections and intermittent bed contact, respectively. Optical measurements reveal locally high grain concentrations at some elevations below 561mm; these heights scale with transport rate, mass flux gradient and wind speed. Copyright 08 1999 John Wiley & Sons, Ltd.
[33] Dong Z B, Liu X P, Wang H T, et al.2002.

The flux profile of a blowing sand cloud: a wind tunnel investigation

[J]. Geomorphology, 49(3-4): 219-230.

https://doi.org/10.1016/S0169-555X(02)00170-8      URL      [本文引用: 1]      摘要

The flux profile of a blowing sand cloud, or the variation of blown sand flux with height, is the reflection of blown sand particles that move in different trajectories, and also the basis for checking drifting sand. Here we report the wind tunnel results of systematic tests of the flux profiles of different sized sands at different free-stream wind velocities. The results reveal that within the 60-cm near-surface layer, the decay of blown sand flux with height can be expressed by an exponential function: q h = a exp(鈭 h / b ), where, q h is the blown sand transport rate at height h , a and b are parameters that vary with wind velocity and sand size. The significance of coefficient a and b in the function is defined: a represents the transport rate in true creep and b implies the relative decay rate with height of the blown sand transport rate. The true creep fraction, the ratio of the sand transported on the surface ( h =0) to the total transport varies widely, decreasing with both sand size and wind speed. The flux profiles are converted to straight lines by plotting sand transport rate, q h , on a log-scale. The slope of the straight lines that represents the relative decay rate with height of sand transport rate decreases with an increase in free-stream wind velocity and sand grain size, implying that relatively more of the blown sand is transported to greater heights as grain size and wind speed increase. The average saltating height represented by the height where 50% of the cumulative flux percentage occurs increases with both wind speed and grain size, implying that saltation becomes more intense as grain size and/or wind velocity increase.
[34] Dong Z B, Qian G Q.2007.

Characterizing the height profile of the flux of wind-eroded sediment

[J]. Environmental Geology, 51(5): 835-845.

https://doi.org/10.1007/s00254-006-0363-5      URL      Magsci      [本文引用: 1]      摘要

Wind erosion causes severe environmental problems, such as aeolian desertification and dust storms, in arid and semiarid regions. Reliable prediction of the height profile of the wind-eroded sediment flux is crucial for estimation of transport rates, verification of computer models, understanding of particle-modified wind flows, and control of drifting sand. This study defined the basic height profile for the flux of wind-eroded sediment and the coefficients that characterize its equation. Nine grain-size populations of natural sand at different wind velocities were tested in a wind tunnel to measure the flux of sediment at different heights. The resulting flux profiles resemble a golf club with a small back-turn where the flux increases with increasing height within 20聽mm above the surface. If the small back-turns are neglected, the flux profiles can be expressed by an exponential-decay function $ q_{{\text{r}}} (z) = a{\text{e}}^{{ - bz_{r} }} , $ where q r ( z ) is the dimensionless relative flux of sediment at height z , which follows the exponential-decay law proposed by previous researchers for aeolian saltation. Three coefficients (a creep proportion, a relative decay rate, and an average saltation height) are proposed to characterize the height profile. Coefficients a and b in the above equation represent the creep proportion and relative decay rate as a function of height, respectively. Coefficient a varies widely, depending on grain size and wind velocity, but averages 0.09. It is suggested that the grain size and wind velocity must be specified when discussing creep proportion. Coefficients a and b are nearly linearly correlated and decrease as grain size and wind velocity increase. The average saltation height (the average height sediment particles can reach) was a function of grain size and wind velocity, and was well correlated with coefficients a and b .
[35] Dong Z B, Lv P, Zhang Z C, et al.2014.

Aeolian transport over a developing transverse dune

[J]. Journal of Arid Land, 6(3): 243-254.

https://doi.org/10.1007/s40333-013-0243-2      URL      Magsci      [本文引用: 4]      摘要

The spatial and temporal changes in aeolian transport over a dune are fundamental factors that control the morphology of the dune. In the present study, we obtained direct field observations of aeolian transport over a developing transverse dune at the Shapotou Aeolian Experiment Site in the southeastern part of China鈥檚 Tengger Desert. The transport rate versus wind speed relationship is complicated over a developing dune compared with the relationships over flat surfaces and over dunes that are in equilibrium with the wind. We obtained trend lines for transport rate over the transverse dune versus distance. The transport rate generally increased from the toe to the crest above the stoss slope, but the difference in transport rate between the crest and the toe was smaller than those that have been proposed for taller dunes. The crest/toe ratio for transport rates therefore seems to depend greatly on dune height. Flux density profiles for different points above the dune at different wind speeds were well described by the exponential decay law, as has been proposed for saltation flux density profiles. Coefficients in the flux density profile function can be defined in terms of the transport rate and wind speed. However, the dependence of relative decay rate with height and average saltation height on wind speed was weaker than that observed in a wind tunnel and above a flat surface. The preliminary results obtained in this study require more evidence from field observations to fully describe aeolian transport above developing dunes.
[36] Fryrear D W, Stout J E, Hagen L J, et al.1991.

Wind erosion: field measurement and analysis

[J]. Transactions of the ASAE, 34(1): 155-160.

https://doi.org/10.13031/2013.31638      URL      [本文引用: 1]      摘要

ABSTRACT
[37] Iversen J D, Rasmussen K R.1994.

The effect of surface slope on saltation threshold

[J]. Sedimentology, 41(4): 721-728.

https://doi.org/10.1111/j.1365-3091.1994.tb01419.x      URL      [本文引用: 1]      摘要

ABSTRACT This report on the first set of experiments in the new wind tunnel concerns the effect of slope on threshold friction speed. Shows that, provided the effects of Reynolds number variation and interparticle cohesive force are accounted for, the static friction angle a is independent of slope and close in value to the measured static angle of response. -from Authors
[38] Lancaster N, Baas A.1998.

Influence of vegetation cover on sand transport by wind: field studies at Owens Lake, California

[J]. Earth Surface Processes and Landforms, 23(1): 69-82.

https://doi.org/10.1002/(SICI)1096-9837(199801)23:1<69::AID-ESP823>3.0.CO;2-G      URL      [本文引用: 1]      摘要

Abstract Field studies conducted at Owens Lake, California, provide direct measurements of sand flux on sand sheets with zero to 20 per cent cover of salt grass. Results from 12 different sand transport events show that aerodynamic roughness length and threshold wind shear velocity increase with vegetation cover as measured by vertically projected cover and roughness density (位). This results in a negative exponential decrease in sediment flux with increasing vegetation cover such that sand transport is effectively eliminated when the vertically projected cover of salt grass is greater than 15 per cent. A general empirical model for the relation between sand flux and vegetation cover has been derived and can be used to predict the amount of vegetation required to stabilize sand dune areas. 漏 1998 John Wiley & Sons, Ltd.
[39] Ni J R, Li Z S, Mendoza C.2003.

Vertical profiles of aeolian sand mass flux

[J]. Geomorphology, 49(3-4): 205-218.

https://doi.org/10.1016/S0169-555X(02)00169-1      URL      [本文引用: 1]      摘要

Vertical profiles of the horizontal mass flux of blown sand are investigated experimentally using a passive vertical array in a wind tunnel. Considering lower sampling efficiency of the sand trap in the near-bed region, this investigation is complemented by the measurements of the longitudinal profiles of mass flux made using a horizontal sand trap. The experiments were conducted with two test sands and five different stream velocities.In the upper part of the vertical profile, the measured data exhibit an exponential decay distribution with a positive deviation occurring in the near-bed region. The measured longitudinal profiles are similar to the measured vertical profiles. Linking both profiles and the modes of sand transport, it is possible that saltating sand grains give rise to the well-known exponential decay distribution of mass flux, and that creeping and reptating grains force a deviation from it. A simple equation applicable for both the vertical and the longitudinal sand mass flux variations is introduced and the parameters are estimated from experimental data.
[40] Rotnicka J.2013.

Aeolian vertical mass flux profiles above dry and moist sandy beach surfaces

[J]. Geomorphology, 187: 27-37.

https://doi.org/10.1016/j.geomorph.2012.12.032      URL      [本文引用: 1]      摘要

The vertical distribution of aeolian mass flux was investigated in a natural beach environment. Field experiments conducted on the beach of the Leba Barrier, southern Baltic coast, Poland, measured the sand transport rate and the vertical mass flux distribution above dry rippled sand and a moist flat sandy surface. The experiments were intended to show the changes in the vertical distribution of sand with changing wind speed. All the data represent saturated flux conditions. Sand transport was measured using 0.5 m-high vertically segmented passive sand traps, while the wind speed and direction were monitored at 1 m elevation. The obtained dataset comprises 65 measurements on dry surfaces and 51 measurements on moist sandy surfaces. The sand transport rate above the moist surface was up to 90% higher than above the dry surface for wind speeds of 7-11 m/s, but higher velocities gave smaller differences between the surfaces. The saltation layer was thicker above the moist surface than above the dry surface. All the vertical sand flux profiles are best described by exponential decay functions. Analysis of the normalised flux profiles grouped by wind velocity shows that the fitted curves are less inclined for moist surfaces than dry surfaces. Moreover, the regression coefficients depict a marked trend in which the intercept decreases and the slope increases with increasing wind speed; this indicates that more sand is transported at higher elevations above the bed and less at lower elevations. The proportion of total transport seems to be independent of wind speed at elevations of approximately 35 mm and 50 mm above the dry and moist surfaces, respectively. Differences between the measured- and exponential-fit values of mass flux are particularly distinct close to the bed, where the exponential fit either over- or under-predicts the measured values. Over-predictions occur in weaker winds (up to 6-7 m/s), whereas under-predictions become more pronounced as the wind becomes stronger and when the layer in which the under-prediction occurs thickens. The under-predictions are particularly obvious above the moist surface; it is not clear whether this phenomenon is due to technique measurement error or to another source. The proportion of creep is often considered to be responsible for the difference from the exponential fit which represents the saltation mode of aeolian transport. This proportion is difficult to determine because the mass flux measured by the lowermost chamber of the sand trap used in the experiments represents sand transported in both saltation and creep or/and reptation. (C) 2013 Elsevier B.V. All rights reserved.
[41] Williams G.1964.

Some aspects of the eolian saltation load

[J]. Sedimentology, 3(4): 257-287.

https://doi.org/10.1111/j.1365-3091.1964.tb00642.x      URL      [本文引用: 1]      摘要

First page of article
[42] Zheng X J, He L H, Wu J J.2004.

Vertical profiles of mass flux for windblown sand movement at steady state

[J]. Journal of Geophysical Research: Solid Earth (1978-2012), 109(B1): B01106.

https://doi.org/10.1029/2003JB002656      URL      [本文引用: 1]      摘要

Abstract Top of page Abstract 1.Introduction 2.Fundamental Model for Saltation 3.Numerical Program 4.Numerical Examples 5.Results and Analyses 6.Conclusions Acknowledgments References Supporting Information [1] A profile pattern different from the generally accepted one that mass flux exponentially decreases with the height is indicated by several experimental and theoretical studies and field observations on aeolian sediment transports; however, a theoretical explanation for such a pattern is still absent. To overcome this difficulty, a new model is suggested in this paper, in which the interaction between the saltation of sand grains and the winds is considered, the probability distribution function of vertical liftoff velocities of grains is used to obtain all probable trajectories of saltating grains, and the steady state of the windblown sand movement is reached by adjusting the surface ejection flux (the number ejected per unit area of the bed per unit time). The validity of the model is confirmed by comparing the numerical results of streamwise sand transport versus wind velocity with those calculated from the well-known empirical formulas of Bagnold and Kawamura in their respective effective regions and by comparing the mass flux profile with Yin's observation in the gravel desert. The vertical profile of the mass flux of windblown sand movement obtained obviously displays a stratification pattern composed of a linear increment layer, a saturation layer, and a monotonic decrement layer. The numerical results also elucidate that the stratification patterns of the steady mass flux profiles are not influenced by the electrification force, the wind velocity, and the distributions of vertical liftoff velocities of sand grains, while the peak value of mass flux may occur at different heights, and tend to shift upward with increasing wind velocity.

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