Aeolian sediment fluxes measured over various plant/soil complexes in the Chihuahuan desert
Aeolian sediment fluxes measured over various plant/soil complexes in the Chihuahuan desert
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DOI：
10.1029/2009jf001543
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发表时间：
2010-09-30
影响因子：
3.9
通讯作者：
Gillette, D. A.
中科院分区：
文献类型：
--
作者：
Bergametti, G.;Gillette, D. A.
1998-2005年期间，在Jornada长期生态研究站点内的不同植被区进行了沉积物水平通量的测量。沉积物收集器样品连续标称3个月期间，在15个站点：三个独立的网站，在每一个五个主要的植物/土壤复合体中遇到的这部分奇瓦瓦沙漠（牧豆树，杂酚油，tarbush，格拉玛草，和playa草）。牧豆树植被区有显着较高的沉积物通量比其他四个植物/土壤复合体。其他类型的植被复合体产生的沉积物通量，不能从统计上相互区分。沉积物通量的时间变异性的分析表明，只有每年的沉积物通量从牧豆树网站与每年发生的高风速。沉积物通量的垂直剖面和快速响应Sensit测量的检查证实，当地的跃移机制是负责在牧豆树站点测量的沉积物通量。然而，当地的跃移机制不能解释非牧豆树网站上测得的沉积物通量。沉积物通量在nonmesquite网站很少进行的逆风来源。此外，我们的沉积物通量的数据表明，场外（漂流）通量的沉积物不能解释牧豆树和nonmesquite沉积物通量的差异。我们建议沙尘暴的机制，导致沉积物排放在nonmesquite和mesquite土地，但它们的效果是微不足道的相比，在mesquite网站的中尺度气象风所造成的通量。
Measurements of horizontal flux of sediment were performed over the period 1998-2005 at different vegetated areas within the Jornada Long Term Ecological Research site. Sediment trap samples were collected during successive nominal 3-month periods at 15 sites: three independent sites at each of the five dominant plant/soil complexes encountered in this part of the Chihuahuan desert (mesquite, creosote, tarbush, grama grass, and playa grass). Mesquite vegetated areas have significantly higher sediment fluxes than the four other plant/soil complexes. The other types of vegetation complexes yield sediment fluxes that cannot be statistically distinguished from each other. An analysis of the temporal variability of the sediment fluxes indicates that only the annual sediment fluxes from mesquite sites are correlated with the annual occurrence of high wind speeds. Examination of the vertical profile of the fluxes of sediment and the fast response Sensit measurements confirms that a local saltation mechanism is responsible for sediment fluxes measured at mesquite sites. However, the local saltation mechanism cannot explain sediment fluxes measured on nonmesquite sites. Sediment fluxes at nonmesquite sites are only rarely carried in from upwind sources. Additionally, our data for sediment flux showed that off-site (drifting in) flux of sediment cannot explain the differences of mesquite and nonmesquite sediment fluxes. We suggest dust devils to be the mechanism that causes sediment emissions at both nonmesquite and mesquite lands, but their effect is trivial compared to the fluxes caused by mesoscale meteorological winds at the mesquite sites.