Turbulence Intermittency for Cloud Physics (TITCHY)

云物理的湍流间歇性 (TITCHY)

• 批准号: EP/Z000149/1
• 负责人: Oliver Buxton
• 金额: $ 221.74万
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FZ000149%2F1
• 关键词: Turbulence; Intermittency; Cloud; Physics; TITCHY

Since the dawn of humankind people have looked up at the sky, perhaps projected every day images into the dazzling variety of shapes that cumulus clouds produce, and asked "why do clouds form and then disappear?" and "why does it rain?" To this day these questions remain unanswered, although of course our understanding of the physics of clouds has advanced enormously. It has been provocatively asked "can we understand clouds without turbulence?" to which my response is a resounding "no!" Clouds grow by entraining environmental air across the sharply defined visible boundary of the cloud. Similarly they decay through precipitation, and more importantly the detrainment of air back to the environment. Neither of these processes are well understood. In recent years I have jump started the field of entrainment between two adjacent regions of turbulence, or turbulent/turbulent entrainment (TTE) which is precisely the scenario that occurs for a warm cumulus cloud in the turbulent atmospheric boundary layer. Entrainment dilutes a cloud and fundamentally alters its microphysics, yet TTE for a cloud is not understood in part because of its inherent intermittency. Without understanding the TTE of water mass, energy, momentum, buoyancy, and heat into a cloud it is not possible to parameterise it and thereby improve weather/climate forecasts. TITCHY will do this, through a carefully co-articulated campaign of state-of-the-art experiments and simulations specifically devised to assess the importance of my TTE paradigm to cloud microphysics. The second thrust of TITCHY is to examine the physics of water droplets within a cloud; in particular the forces that act on them and how they affect the collision/coalescence process that ultimately yields raindrops. These forces are subject to intermittent turbulent physics hitherto neglected but potentially of critical importance. Based on my transformative new ideas, TITCHY seeks to tackle a centuries-old problem with a modern outlook.

自从人类的黎明抬头看着天空以来，也许每天都会将图像投射成云云产生的各种形状，并问“为什么云形成然后消失？”和“为什么下雨？”直到今天，这些问题仍未得到答案，尽管当然，我们对云的物理学的理解已经大大提高了。被挑衅地问：“我们可以理解云而没有动荡吗？”我的回应是一个响亮的“不！”云通过遍布云的明确可见边界的环境空气而生长。同样，它们通过降水而腐烂，更重要的是，空气降低回到环境。这些过程都没有很好地理解。近年来，我跳了起来，在两个相邻的湍流区域或湍流/湍流夹带（TTE）之间开始夹带，这正是在湍流大气边界层中温暖的积云云发生的情况。夹带稀释云，从根本上改变了其微物理学，但由于其固有的间歇性而言，云的TTE尚未理解。在不了解水质量，能量，动量，浮力和热量中的TTE中，不可能对其进行参数化，从而改善天气/气候预测。 Titchy将通过精心策划的最新实验和模拟运动，专门为评估我的TTE范式对云微物理学的重要性而进行的精心开展的运动。 Titchy的第二个推力是检查云中的水滴物理。特别是对它们作用的力以及它们如何影响最终产生雨滴的碰撞/结合过程。这些力量受到迄今忽视但可能至关重要的间歇性湍流物理学的影响。基于我的变革性新想法，Titchy试图通过现代前景解决一个世纪以上的问题。