Atmospheric boundary-layer studies and aeolian processes

无论是夏季沙尘暴从草原农场移走表层土壤，沙漠中的沙尘暴，火星上的沙尘暴，还是漂移和吹雪导致能见度降低和其他危害，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，但仍然存在的不确定性和困难是如何对待在空气(或水)中吹来的物质与下垫面之间的相互作用。蠕变、跳跃和悬浮是这一过程中不同阶段的特征，这是已知的，但尽管进行了多年的研究，但缺乏连贯的建模策略。我们自己最近在地球上吹雪和在火星上吹尘埃的工作(与NASA/CSA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，推动了对风沙输送过程这一方面的基础研究，作为我们正在进行的大气边界层流动研究的主要部分。这项研究的方法将围绕湍流大气边界层流动的计算机模拟，有无悬浮和跳跃粒子的存在。我们从我们自己正在进行的北极、亚北极、马尼托巴省和安大略省吹雪的实地研究中获得数据，并将利用这些数据来产生想法，并为测试我们开发的模型提供数据。我们也是凤凰号火星任务的积极参与者，一旦2008年着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沙过程风洞中进行研究，并使用高分辨率摄影技术来研究颗粒表面的相互作用。在雪的情况下，增加了复杂性，因为颗粒可以升华或部分升华，从冰到水蒸气，从而改变它们的大小或完全消失。我们已经用我们的PIEKTUK(吹雪)模式模拟了这些过程，但还需要在我们的拉格朗日模拟研究中表示它们。拉格朗日模拟是一种随机游走模型，它模拟了颗粒在湍流中的运动。

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.