The flow of air in the atmosphere affects our lives in many ways. It drives weather systems across land and sea. It can affect the quality of the air we breathe. It can make a plane ride turbulent and bumpy. The study of how air moves in the atmosphere is called atmospheric dynamics. Atmospheric dynamics studies all altitudes – from the troposphere where we live, though the stratosphere where we fly, and above that into the mesosphere, thermosphere, ionosphere, and to the very edge of space. These layers of the atmosphere are linked; as air moves in these layers, energy can be transferred between them. Better understanding of the movement of energy and air in the upper layers of the atmosphere helps us better understand the dynamics throughout the whole atmosphere.

One way air and energy flow through the atmosphere is in the form of waves. Although we can't observe them as easily as waves on a body of water, similar waves occur in the atmosphere. Like water waves, atmospheric waves can be gentle, like when the wind is slow and only small, smooth waves form. Or atmospheric waves can be turbulent, like whitecaps that form when fast moving air flows over the water. And like waves in the water, atmospheric waves can move great distances, both horizontally and vertically. Atmospheric waves and their energy transfer are the focus of this research. We report three interesting findings from this research project.

Large water waves called tsunamis can follow large earthquakes. Tsunami prediction and tracking helps alert vulnerable communities to danger from these potentially devastating waves. Tsunamis are difficult to track on the open ocean, in part because they have exceedingly large length scales (over 100 miles) and very small wave heights, or amplitudes (shorter than 2 ft). Nevertheless, these small amplitude disturbances create waves in the air. These newly formed atmospheric waves also have very small amplitudes, and they move vertically through the atmosphere. As the waves move vertically, their amplitudes grow. The waves carry energy into upper layers of the atmosphere. If these waves reach high enough into the ionosphere, scientists who monitor this region may be able to detect them and issue tsunami warnings faster and more reliably than current methods. However, wind between the Earth's surface and the ionosphere could change the amount of energy that reaches those upper layers; they may not reach the altitude where they can be detected. Our research explores the propagation of these waves under a variety of wind conditions. Our models confirm that these waves can reach the ionosphere under many wind conditions. Our next step is to collaborate with scientists who model electrons in the ionosphere, so that we can then work with with scientists who monitor this region of the atmosphere. This research has been an important step in developing real-time tsunami monitoring.

A second part of this research explores other ways in which vertically propagating waves interact with the atmosphere. When atmospheric waves break, like whitecaps on the water, their energy and momentum are deposited to flow in the surrounding atmosphere. This is one specific way that energy can be transported between parts of the atmosphere. Predicting how waves will travel through the atmosphere, when they will break, and how that energy affects the surrounding atmosphere depends on atmospheric conditions such as wind and temperature profiles, atmospheric stabili...

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