Parametrization of the increase of the aeolian erosion threshold wind friction velocity due to soil moisture for arid and semi-arid areas
Parametrization of the increase of the aeolian erosion threshold wind friction velocity due to soil moisture for arid and semi-arid areas
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DOI：
10.1007/s005850050744
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发表时间：
1999-01-01
期刊：
影响因子：
--
通讯作者：
Bergametti, G
中科院分区：
文献类型：
--
作者：
Fécan, F;Marticorena, B;Bergametti, G
半干旱地区土壤扬尘的大规模模拟需要考虑土壤湿度对风蚀阈值的影响。土壤保水力由土壤颗粒表面的分子吸附和颗粒之间的毛细管力组成。当土壤湿度增加时，颗粒间毛细管力（以水分张力为特征）是造成风蚀阈值增加的主要因素。当土壤含水量接近但小于最大吸附水量 w'（取决于土壤质地）时，这些毛细管力被认为不足以显着增加侵蚀阈值。水分张力与土壤水分和 w' 的函数关系的表达式是从保留曲线得出的。根据该表达式，已将干湿侵蚀阈值的比率参数化为土壤湿度和土壤质地的函数。该参数化的系数是通过使用文献中的实验数据来确定的。 w' 和土壤粘土含量之间的经验关系已经建立。发现针对不同土壤质地模拟的侵蚀阈值比率与实验数据非常吻合。
Large-scale simulation of the soil-derived dust emission in semi-arid regions needs to account for the influence of the soil moisture on the wind erosion threshold. Soil water retention consists of molecular adsorption on the soil grain surface and capillary forces between the grain. Interparticle capillary forces (characterized by the moisture tension) are the main factor responsible for the increase of the wind erosion threshold observed when the soil moisture increases. When the soil moisture content is close to but smaller than the maximum amount of adsorbed water, w' (depending on the soil texture), these capillary forces are considered as not strong enough to significantly increase the erosion threshold. An expression of the moisture tension as a function of soil moisture and w' is derived from retention curves. From this expression, a parametrization of the ratio of the wet to dry erosion thresholds has been developed as a function of soil moisture and soil texture. The coefficients of this parametrization have been determined by using experimental data from the literature. An empirical relationship between w' and soil clay content has been established. The erosion threshold ratios simulated for different soil textures were found to be in good agreement with the experimental data.