Waves in the Lower Atmosphere

这项研究的目的是探索波状扰动是如何在低层大气中产生的，这些波是如何促进湍流和混合的，以及这些波是如何影响风暴和涡线等恶劣天气事件的位置的。意向波是重力波，是波长从几百米到数百公里的有序扰动，周期从几分钟到一天的很大一部分。这些波的规模和其他一些物理特征使它们能够与气象系统强烈相互作用，如风暴、阵风、狂风线和导致大气混合的湍流。自1950年S以来，人们已经认识到这些波在气象学中的重要性，但学习如何将波理论应用于实际情况的挑战仍然存在。波动理论本身仍然是不完整的，特别是关于许多波的起源以及它们在达到大振幅时的行为。这一建议研究了一种在工程应用中备受关注，但在气象学中却被忽视的波浪产生机制，即Jeffreys阻力机制。这种机制起源于流体在粗糙的表面上移动时所经历的摩擦--在气象背景下，粗糙的表面是指地球表面。驱动流体运动的力和与流动相反的表面力的性质不同，可能会导致平行于表面的基本流动破裂：流动中出现波动扰动，从驱动运动的力中提取能量。以前对这一过程的研究表明，它可能非常有效地产生大气波，然后破裂，产生混合和湍流。研究还表明，这一过程导致了与恶劣天气频段相关的更强、更大尺度的波浪。该理论将进一步发展，并用于解释特定的气象事件，可能是在东南部。

The object of this research is to explore how wavelike disturbances are created in the lower atmosphere, how these waves contribute to turbulence and mixing, and how these waves influence the location of severe weather events such as storms and squall lines. The waves of intent are gravity waves, ordered disturbances with wavelengths ranging from a few hundred meters to many hundreds of kilometers, and periods ranging from a few minutes to large fractions of a day. The scales of these waves and some other physical characteristics allow them to interact strongly with meteorological systems such as storms, gusts, squall lines, and the turbulence that leads to atmospheric mixing. The importance of these waves in meteorology has been recognized since the 1950's, but the challenge of learning how to apply the wave theory to practical situations remains. The wave theory itself is still incomplete, particularly with respect to the origin of many of the waves and how they behave when they reach large amplitudes. This proposal studies a wave generation mechanism that receives attention in engineering applications, but has been rather neglected in meteorology, Jeffreys' drag mechanism. The mechanism originates with the friction that a fluid experiences as it moves over a rough surface - in the meteorological context, the surface of the earth. The disparate natures of the forces that drive the motion of the fluid and the surface forces that oppose the flow can result in a breakdown of basic flows parallel to the surface: wavelike disturbances appear in the flow, extracting energy from the forces that drive the motion. Previous studies of this process suggest that it may be very effective in producing the atmospheric waves that break to produce mixing and turbulence. The studies also indicate that the process contributes to the strong, larger-scale waves associated with bands of severe weather. The theory will be developed further and used to interpret particular meteorological events, prob ably in the Southeast.