中国沙漠地区降尘特征与影响因素分析  

Dustfall Characteristics and Affect Factors in Chinese Desert Region

作　　者：樊恒文[1] 肖洪浪[1] 段争虎[1] 李新荣[1] 李涛[1] 李金贵[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙坡头沙漠试验研究站,甘肃兰州730000

出　　处：《中国沙漠》2002年第6期559-565,共7页Journal of Desert Research

基　　金：中国科学院寒区旱区环境与工程研究所创新项目 ( 2 10 0 2 8);国家自然科学基金项目 ( 40 0 0 50 0 2 )资助

摘　　要：1991— 1 998年期间先后使用积尘器在 4个地形剖面上监测了沙坡头地区的降尘过程。降尘沉积速率平均 4 866kg·hm- 2 ·a- 1 ,降尘沉积具有明显的时空分异规律 ,月最大沉积于每年的 5月发生在丘间低地 ,这是因为每年的 5月份既是区域冬夏季风场的转换季节 ,又是人类活动破坏地表的时期 ,并受地貌沉积模式的影响 ;较小的月沉积于冬季出现在丘顶部位。降尘的粒径集中在 2～ 2 50 μm ,极细砂占总量的 37 1 6 % ,沉积物属于砂壤质地。Si、Al、Fe、Ca、K、Na、Mg、Ti等 8个元素构成检出元素总量的 99 53 %。 1 0～ 2 50 μm的尘屑中含有 30种重矿物 ,其中易风化矿物占 56 75 %～ 74 32 %。风尘相关分析发现月降尘量与每月 >5m·s- 1 风速的次数有良好的相关性。The dust\|fall depositions were monitored with dust trappers on the four topographical transections in the Shapotou area from 1991 to 1998. The deposition velocity averaged \{4 866\} kg\5hm -2 yearly. The dust deposition had obvious temporal and spatial patterns. The maximal monthly depositions were observed during May of every year at the dune hollows, because the May of every year was both a conversion season from winter wind to summer wind in the region and a period when human activities destroyed the surface, and topographical pattern influenced the deposition. Smaller depositions appeared on the crests during the winter. The particle size of the deposition distributed between 2～250 μm. The very fine sand occupied 37\^16% of the total deposition. The texture of the deposition belonged sandy loam. The eight elements, Si, Al, Fe, Ca, K, Na, Mg and Ti made up of 99\^53% of the element total. In the particles within 10～250 μm contained 30 heavy minerals, in which weathering minerals occupied 56\^75%～74\^32%. The relative analysis between wind factors and dust deposition displayed that there was a good relativity between the monthly depositions and the monthly times of >5 m\5s -1 wind speed.

关 键 词：降尘沉积 时空模式 元素和重矿物 沙漠黄土过渡带 

分 类 号：P445.4[天文地球—大气科学及气象学]