Snowdrift Suspension And Atmospheric Turbulence. Part II: Results Of Model Simulations
Snowdrift Suspension And Atmospheric Turbulence. Part II: Results Of Model Simulations
复制标题
DOI：
10.1023/a:1002643921326
复制
发表时间：
2000-06
影响因子：
4.3
通讯作者：
R. Bintanja
中科院分区：
文献类型：
--
作者：
R. Bintanja
本文利用一个大气近地层模式研究了悬浮雪粒子与近地面气流的相互作用。模型考虑了48个尺度雪粒的向上扩散、重力沉降和升华作用，雪堆升华作用对近地层热量和水分收支的影响，以及悬浮粒子对湍流动能的浮力破坏作用。在E-ε闭合模型中增加了一个新的项，代表悬浮颗粒对浮力的破坏。一般情况下，模型结果表明，悬浮颗粒的存在下，TKE，耗散率，湍流长度尺度和涡交换系数（高达40%）显着减少。结果表明，涡动交换系数的减小主要是由于湍流长度尺度的减小。伴随粒子的Richardson数在跃移-悬浮界面附近达到峰值，但在表层较高的水平，粒子诱导的浮力也会显著影响流动。详细分析了各种雪堆数量，TKE预算和颗粒浮力对流动的影响。
An atmospheric surface-layer model is used to investigate the interactionbetween suspended snow particles and the near-surface flow. Themodel incorporates the effects of upward diffusion, gravitational settling and sublimation of snow particles in 48 size classes, the effects of snowdrift sublimation on the heat and moisture budget of the surface layer, and the buoyancy destruction of turbulent kinetic energy (TKE) caused by the presence of suspended particles. A new term in the E-ε closure model representing the buoyancy destruction due to suspended particles is included in the prognostic equation for TKE. Generally, model results indicate that the presence of suspended particles causes significant decreases in TKE, the dissipation rate, turbulent length scales and eddy exchange coefficients (up to 40%). It is found that the reduction in the eddy exchangecoefficients is due mainly to reductions in turbulent length scales. Theassociated particle Richardson number peaks near the saltation-suspensioninterface, but at higher levels in the surface layer the particle-induced buoyancy can also significantly affect the flow. A detailed analysis of the various snowdrift quantities, the TKE budget and the particle buoyancy effects on the flow is presented.