A SIMPLE-MODEL OF DRAINAGE FLOW ON A SLOPE
A SIMPLE-MODEL OF DRAINAGE FLOW ON A SLOPE
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DOI：
10.1007/bf00153975
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发表时间：
1988-04-01
影响因子：
4.3
通讯作者：
SATO, T
中科院分区：
文献类型：
--
作者：
KONDO, J;SATO, T
为了描述排水流的整体特性，引入了冷空气“包裹”的概念。利用基于平静条件下动量和感热输运的模型，以简单形式推导出了包裹的厚度h和速度u。由图可知，h和u对应于实际排水流的反演高度和最大流速。h和u的控制参数为坡面长度和垂直落差、周围大气与包裹体的势温差、平均体积系数表示的坡面气动条件和环境稳定性。平均体积系数取决于速度和势温剖面的粗糙度长度，并且是斜率长度的递减函数。在中性环境分层下，包裹模型与Manins和Sawford（1979）的模型在质量上是一致的。但在稳定条件下，一致性不是很好。包块模式预测的排水流厚度和流速与在几十米至几百公里长的斜坡上的观测结果一致。
The concept of a cold air ''Parcel'' is introduced for describing the bulk properties of drainage flow. By means of a model based on the momentum and sensible heat transports under calm conditions, the thickness h and velocity u of the Parcel are derived in simple forms. It is shown that h and u correspond to the inversion height and maximum velocity of actual drainage flow. The governing parameters for h and u are the length and vertical drop of the slope, potential temperature difference between the ambient atmosphere and the Parcel, aerodynamic condition of the slope surface expressed by the mean bulk coefficients, and ambient stability. The mean bulk coefficients depend on the roughness lengths for the velocity and potential temperature profiles and are decreasing functions of the slope length. The Parcel Model agrees qualitatively with Manins and Sawford''s (1979) model under neutral ambient stratification. But agreement is not so good under stable conditions. The thickness and velocity of drainage flow predicted by the Parcel Model agree with observations on slopes several tens of meters to several hundred kilometers long.