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。
Based on long time monitoring data at Dengkou Desert Ecology Station and observation data from various of sand traps in 2011,aeolian-sand flow structure at 0~100 cm is analyzed over five typical types of underlying surface which include moving dune,Artemisia ordosica semi-fixed dune,Nitraria tanqutorum semi-fixed dune,Artemisia ordosicafixed dune and Nitraria tanqutorumfixed dune in northeastern margin of the Ulanbuh Desert.The results show:(1)The sand transport rate(q)decreases with the increase of height(h)in power function q=a×h-b(R2≥0.8409),and increases with the increase of wind velocity(v)in power function q=avb,(R2≥0.9256);The sand transport flux in 0-10 cm accounts for42.8%-70.7%,and the sand transport flux in 0-30 cm accounts for 67.6%-90.0%.When vegetation coverage is 40%,sand transport rate is 6.6%of moving dune with no vegetation cover,and surface wind erosion can be effectively prevented.(2)Sand materials mainly are composed of fine sand and very fine sand(50-250μm).Wind erosion sand grain size composition at each height follows unimodal distribution,and the peak is between 100-250μm.With the increase of height,wind erosion sand grain size range become more narrow,and grain size become more fine.(3)The driving-sand wind direction concentrates at WNW and NW accounting for 53.19%.The directional distribution of saltation aeolian-sand flow and creep aeoliansand flow should be almost the same in theory,and differences are mainly caused by directions of wind intensity and duration.
出处
《中国沙漠》
CSCD
北大核心
2014年第5期1200-1207,共8页
Journal of Desert Research
基金
国家科技支撑计划项目(2012BAD16B0103)
国家林业科技推广项目([2012]31号)
中央级院所基本科研业务专项项目(CAF-YBB2011005-6)资助
关键词
风沙流结构
输沙率
粒度
乌兰布和沙漠
aeolian-sand flow structure
sand transport rate
grain size
Ulanbuh Desert
