MODELING THE ATMOSPHERIC DUST CYCLE .1. DESIGN OF A SOIL-DERIVED DUST EMISSION SCHEME
MODELING THE ATMOSPHERIC DUST CYCLE .1. DESIGN OF A SOIL-DERIVED DUST EMISSION SCHEME
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DOI：
10.1029/95jd00690
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发表时间：
1995-08-20
影响因子：
4.4
通讯作者：
BERGAMETTI, G
中科院分区：
文献类型：
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作者：
MARTICORENA, B;BERGAMETTI, G
设计了一种土壤来源的沙尘排放方案，为处理沙漠沙尘循环模拟的大气输送模式提供了沙漠沙尘源的显式表示。考虑了土壤可侵蚀表面的两个主要因素：(1)控制侵蚀阈值和排放强度的土壤可侵蚀疏松颗粒的尺寸分布；(2)决定作用于可侵蚀表面的有效风摩擦速度的表面粗糙度。这两个参数通过采用Iversen和White(1982)提出的依赖于尺寸的参数化方法和通过将Arya(1975)导出的阻力分配方案应用于粗糙可侵蚀表面而被包括在阈值风速公式中。这种门槛摩擦速度的参数化已包含在White(1979)提出的水平通量方程中。这允许将特定的生产率归因于每种表面的每种土壤尺寸范围。然后，粉尘通量F被认为是总水平通量G的一部分，此时，比值F/G的值是由土壤粘粒含量施加的。总而言之，计算的质量通量取决于土壤的尺寸分布、粗糙度长度和风摩擦速度。通过与相关实验数据的比较，对该方案的不同步骤进行了独立验证。总体而言，这一协议是令人满意的，因此可以用比以前沙漠尘埃循环模拟中观察到的更少的不确定性来恢复尘埃通量。
A soil-derived dust emission scheme has been designed to provide an explicit representation of the desert dust sources for the atmospheric transport models dealing with the simulation of the desert dust cycle. Two major factors characterizing the erodible surface are considered: (1) the size distribution of the erodible loose particles of the soil which controls the erosion threshold and the emission strength and (2) the surface roughness which imposes the efficient wind friction velocity acting on the erodible surface. These two parameters are included in a formulation of the threshold wind friction velocity by adapting a size-dependent parameterization proposed by Iversen and White (1982) and by applying to the rough erodible surfaces a drag partition scheme derived from Arya (1975). This parameterization of the threshold friction velocity has been included in an horizontal flux equation proposed by White (1979). This allows to attribute a specific production rate to each soil size range for each type of surface. The dust flux F is then considered as a fraction of the total horizontal flux G, the value of the ratio F/G being imposed, at this time, by the soil clay content. In summary, the computed mass fluxes depend on the soil size distribution, the roughness lengths, and the wind friction velocity. The different steps of this scheme have been independently validated by comparison with relevant experimental data. Globally, the agreement is satisfying, so that the dust fluxes could be retrieved with less uncertainties than those observed in previous simulations of the desert dust cycle.