Effects of Soil Surface Irregularities on the Diurnal Variation of Soil Broadband Blue-Sky Albedo
Effects of Soil Surface Irregularities on the Diurnal Variation of Soil Broadband Blue-Sky Albedo
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DOI：
10.1109/jstars.2014.2330691
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发表时间：
2015-02-01
影响因子：
5.5
通讯作者：
Orzechowski, Mateusz
中科院分区：
文献类型：
--
作者：
Cierniewski, Jerzy;Karnieli, Arnon;Orzechowski, Mateusz
本文从粗糙度指数的角度定量探讨了土壤表面不规则性对大范围土壤性质的宽带蓝天反照率日变化的影响。对波兰和以色列的耕地和未耕地土壤表面进行了实地研究，这些土壤表面的粗糙度和亮度各不相同。研究发现，这些由不同农业设备形成并通过雨水或喷灌改变的不规则性可以通过两个粗糙度指数来量化。土壤粗糙度不仅影响反照率日变化的总体水平，而且影响从当地正午的太阳天顶角(theta(s))到约75°～80°的日增加强度。粗糙度指数是仅精确确定具有相同颜色值的土壤在当地太阳正午时的反照率的变量。如果将土壤有机碳（SOC）和碳酸钙含量作为主导变量，结合其中一项指标，这三个变量一起可以显着描述所有土壤表面当地太阳正午时的反照率。具有高度不规则性的土壤在θ低于75度时几乎没有表现出反照率的上升值，而光滑的土壤表面在这些角度下表现出反照率逐渐增加。结论是，粗糙度指数提供了足够的手段来准确描述各种表面反照率的日变化，而不考虑其他土壤特性。
This paper quantitatively explores, in terms of roughness indices, the effect of soil surface irregularities on the diurnal variation of the broadband blue-sky albedo of a large range of soil properties. Field studies were carried out on cultivated and uncultivated soil surfaces in Poland and Israel that vary in roughness and brightness. It was found that these irregularities, formed by different agricultural equipment and modified by rain or sprinkler irrigation, can be quantified by two roughness indices. Soil roughness not only affects the overall level of the diurnal variation of the albedo, but also affects the intensity of the diurnal increase from the solar zenith angle (theta(s)) at the local noon to about 75 degrees - 80 degrees. The roughness indices are variables that precisely determine only the albedo at the local solar noon of soils with the same color value. If the contents of soil organic carbon (SOC) and calcium carbonate are treated as the dominant variables, combined with one of the indices, these three variables together would significantly describe the albedo at the local solar noon of all soil surfaces. The soils, with their high irregularities, showed almost no rising values of albedo at a theta(s) lower than 75 degrees, while the smooth soil surfaces exhibited a gradual increase of the albedo at these angles. It is concluded that the roughness indices provide sufficient means to accurately describe the diurnal variation of the albedo of a wide range of surfaces, disregarding other soil properties.