Question

急用啊··那位好心人帮帮我吧··不要在线翻译翻的啊··

A major problem in modelling field-scale water flow and solute transport is related to
the inherent spatial variability of field soils. The need for incorporating statistical
techniques which describe the natural variability in the modelling of the unsaturated
zone has been advocated by Nielsen and Biggar (1982), amongst others.
A common approach of treating spatial variability is to consider the field soil as an
ensemble of parallel and statistically independent tubes assuming only vertical flow.
These stream tubes are usually considered to have parameters that are homogeneous in
the vertical direction. This parallel column concept has been applied to model field-scale
solute transport (Butters et al., 1989; Roth et al., 1991) and variably saturated water flow
in heterogeneous soil (Cordova and Bras, 1982; Dagan and Bresler, 1983, among
others). In these studies, soil properties were considered to be uniform over depth. In
most field soils, however, a natural layering exists and has an important effect on flow
and transport processes (Byers and Stephens, 1983; Eilsworth and Jury, 1991). Extension
of the stochastic approach to a layered system has been reported by Jury and Roth
(1990) and Destouni (1992).
A second approach considers a very detailed description of the heterogeneity of the
medium itself and simulates the detailed hydrodynamics with a two- or three-dimensional
numerical model (Ababou, 1991a). The question arises, however, whether the
enormous amounts of field data will ever be available to fully characterize the fine-scale
heterogeneities and stratification of the soil, required to run this type of model. Also, the
excessive computational resources required to determine the distribution of water
content, pressure head, and fluxes in a three-dimensional space in a heterogeneous field
may be an important drawback and makes this approach impractical.
Prediction of water flow and solute transport in heterogeneous soils is further
complicated by the presence of macropores. Excellent reviews related to macropore flow
are given by Beven and Germann (1982), White (1985), and Bouma (1991). Both
laboratory-scale (McMohan and Thomas, 1974) and field-scale experiments (Devries
and Chow, 1978) have shown that the observed phenomena of water and solute
redistribution in soil containing a considerable amount of large pores could not be
described with Darcian theory. Better predictions of water flow in such types of soil can
be obtained by the use of multi-porosity models. In these models, the macropore soil is
conceptualized as a system of two or more continua: one is related to macropores or
interaggregate pores, whereas the other comprises the matrix domain or soil aggregates.
哎··怎么是在线翻译出来的成果啊···

Answer 1

建模领域的一个重大问题，规模水流和溶质运移是有关
固有的空间变异性土壤的领域。在纳入统计的需要
技术，其中叙述了在模拟自然变异的不饱和
开发区已被尼尔森倡导和比格（1982），除其他。
一种治疗空间变异常用的方法是将之视为一个外地土壤
合奏平行和独立的统计假设只有垂直流管。
这些流管通常被认为有参数，同质
垂直方向。这列平行的概念已经应用到模式的实地规模
溶质运移（巴特斯等。，1989;罗斯等。，1991）和变饱和水流
在异构土壤（科尔多瓦和Bras，1982;大干和布雷斯勒，1983年，除
等）。在这些研究中，土壤性质被认为是对的深度一致。在
大多数外地土壤，然而，自然分层存在，并且对流动的重要作用
和运输过程（拜尔斯和Stephens，1983; Eilsworth和评委，1991）。扩展
在随机方式，以多层次的系统已被报告评审和罗斯
（1990年）和Destouni（1992年）。
第二种方法考虑了对异质性非常详细的描述
媒介和模拟的两个详细的流体力学或三维
数值模型（阿巴布，1991a）。产生的问题，但是，无论是
外地大量的数据都不会提供给罚款的全部特征尺度
非均质性和土壤分层，需要运行这种类型的模式。此外，
过多的计算资源必须确定水的分布
内容，压头，并在三维空间通量在异构领域
可能是一个重要的缺点，并使得这种方法是不切实际的。
水流和非均质土壤溶质运移预测进一步
复杂的大孔的存在。极高的评价与孔隙流
给出的贝文和特格尔曼（1982），白色（1985），和鲍马（1991）。两者
实验室规模（McMohan和托马斯，1974）和实地规模实验（德弗里斯
及周，1978）表明，水和溶质的观察到的现象
在载有相当数量的大孔隙土壤再分配不能
叙述了达西理论。水在这种类型的土壤流量可以更好的预测
获得由使用多孔隙度模型。在这些模型中，土壤的孔隙
概念化为两个或更多的连续体系统：一个是与大孔或
interaggregate毛孔，而其他包括矩阵域或土壤团聚。