摘要
探讨近地层大气降尘量及其颗粒物粒径分布和固沙植被对降尘的控制效应,对评价沙区固沙植被生态功能具有重要意义。利用沙尘水平通量采集器和垂直降尘缸采集了浑善达克沙地多伦县近地层不同高度(50、100和200 cm)沙尘样品,并利用称重法和激光颗粒分析仪分别测定大气降尘量和颗粒物粒径分布特征。结果表明,50、100、120、200 cm高度水平沙尘通量分别为327.1、196.3、199.6、116.4 mg·m~(-2)·h~(-1);50、100、200 cm高度垂直降尘量分别为518.6、270.6、34.6 mg·m~(-2)·h~(-1)。水平沙尘通量中颗粒物粒径主要分布在2μm以下,且随着高度增加,水平沙尘通量中的极细颗粒物含量总体呈增加趋势。垂直降尘颗粒物粒径主要分布在100~250μm范围内,且随着高度增加,200μm及以下粒径的颗粒物含量呈降低趋势,而200μm以上粒径的颗粒物含量则呈增加趋势。乔木林地拦截降尘量高于天然草地,且天然草地拦截大气降尘颗粒物粒径分布在50~150μm之间,乔木林地拦截大气降尘颗粒物粒径分布在150~250μm之间。垂直降尘量或水平沙尘通量随高度增加而减少,而颗粒物粒径分布差异明显;不同固沙植被的降尘量及其颗粒物粒径分布不同。
To discuss the atmospheric dust deposition and the distributing features of particulate matter size or dust control effect of sand-fixing plants is of great significance for evaluating the ecological function of sand-fixing plants in sandy area.In this paper,through collecting the dust samples at different heights(50,100 and 200 cm)near the ground in Duolun County by use of horizontal flux collector of dust and vertical dust deposition gauge,the atmospheric dust deposition and the distributing features of particulate matter size had been separately measured by use of weighting method and laser granulometry.The results showed that the horizontal dust flux at height of 50,100,150 and 200 cm was 327.1,196.3,199.6 and 116.4 mg·m~(-2)·h~(-1),respectively.The vertical dust deposition at height of 50,100 and 200 cm was 518.6,270.6 and 34.6 mg·m~(-2)·h~(-1),respectively.In horizontal dust flux,the particulate matter size was below 2μm,and the content of fine particulate matter presented an increasing trend with the increase of height.The particulate matter size of vertical dust deposition was in the range of 100~250μm,with the increase of height,the content of particulate matter at and below 200μm presented a decreasing trend,while the one above 200μm presented an increasing trend.The dust deposition of arbor forest was higher than natural grassland.The particulate matter size of atmospheric dust fall intercepted by natural grassland was from 50μm to 150μm,while the one was from 150μm to 250μm in arbor forest.The research results show that the vertical dust deposition or horizontal dust flux has decreased with the increasing of height,there is obvious distributing difference of particulate matter size,and the dust deposition and the particulate matter size are different from the different sand-fixing plants.
引文
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