Atmospheric boundary-layer studies and aeolian processes

无论是夏季沙尘暴从草原农场带走表土，沙漠中的沙尘暴，火星上的沙尘暴，还是造成能见度降低和其他危害的漂移和吹雪，风成过程都有许多非常实际的应用。 我们可以对这些湍流中涉及的许多机制进行建模，并且已经这样做了，但是持续的不确定性和困难是如何处理空气（或水）中的材料与下垫面之间的相互作用。在这一过程中的各个阶段的蠕变，跳跃和悬浮的过程是已知的，但缺乏一个连贯的建模策略，尽管多年的研究。我们自己最近关于地球上的吹雪和火星上的尘埃的工作（与美国航天局/加空局的凤凰号着陆器有关），加上最近在模拟悬浮粒子过程方面的成功，促使对风成输送过程的这一方面进行基本研究，作为我们正在进行的大气边界层流动研究的一个主要部分。这项研究的方法将围绕湍流大气边界层流动的计算机建模，有和没有悬浮和跳跃粒子的存在。我们有来自我们自己正在进行的实地研究的数据，在北极，亚北极，马尼托巴和安大略，并将使用这些来产生想法，并提供数据来测试我们开发的模型。我们还积极参与了凤凰号火星使命，一旦2008年登陆器在火星表面就位，我们将获得独特的数据。对于沙尘，我们还将在特伦特大学的风成过程风洞中进行研究，并使用高分辨率摄影技术研究颗粒表面的相互作用。就雪而言，还有额外的复杂性，因为颗粒可以升华或部分升华，从冰变成水蒸气，从而改变它们的大小或完全消失。我们已经用PIEKTUK（吹雪）模型模拟了这些过程，但还需要在拉格朗日模拟研究中表示它们。拉格朗日模拟是一种模拟湍流中颗粒运动的随机游走模型。

Whether it is a summer dust storm removing topsoil from prairie farms, a sandstorm in the desert, a dust storm on Mars or drifting and blowing snow causing reduced visibility and other hazards, there are many very practical applications of aeolian processes.  We can model many of the mechanisms involved in these turbulent flows, and have done so, but a continuing uncertainty and difficulty is how treat the interaction between the material blowing in the air (or water) and the underlying surface. The processes of creep, saltation and suspension that characterise various stages in this process are known, but a coherent modelling strategy is missing, despite many years of research. Our own recent work on blowing snow on Earth and dust on Mars (in connection with the NASA/CSA Phoenix lander), coupled with recent success in modelling suspended particle processes has prompted the fundamental study of this aspect of the aeolian transport process as a major part of our ongoing studies of atmospheric boundary-layer flows. Methods for this study will revolve around computer modelling of turbulent atmospheric boundary-layer flows, with and without the presence of suspended and saltating particles. We have data from our own ongoing field studies of blowing snow, in the Arctic, sub-Arctic, Manitoba and Ontario, and will use these to generate ideas and provide data for testing the models we develop. We are also active participants in the Phoenix mission to Mars and will have access to unique data once that lander is in place on the surface of Mars in 2008. For sand and dust we will also conduct studies in the aeolian processes wind tunnel at Trent University and use high resolution photographic techniques to study particle surface interactions. In the case of snow there are added complications in that particles can sublimate, or partially sublimate, from ice to water vapour, thereby changing their size or completely disappearing. We have already simulated these processes with our PIEKTUK (blowing snow) model, but also need to represent them in our Lagrangian simulation studies. Lagrangian simulation is a type of random walk model which simulates the movement of particles in a turbulent flow.