The Structure and Dynamics of Atmospheric Bores and Solitons As Determined From Remote Sensing and Modeling Experiments During IHOP

Abstract

Solitary waves are a class of gravity waves consisting of a single elevation of finite amplitude that, owing to a balance between nonlinearity and dispersion, propagates without change of form. A family of solitary waves, which is termed a “soliton”, forms as the natural consequence of the evolution of a bore – a type of gravity wave (hydraulic jump) generated as a density current (such as cold air from a thunderstorm) intrudes into a fluid of lesser density, which in the case of the atmosphere, occurs beneath a low-level inversion. These phenomena were observed repeatedly by a multitude of ground-based and airborne remote sensing systems during the sixweek field phase of the International H20 Project (IHOP), even though bores were not one of the primary IHOP objectives (Weckwerth et al. 2004). These observing systems together produced the most extensive set of observations ever collected of the evolving structure of bores, solitons, and solitary waves. In spite of this, a more complete understanding of the dynamics of these phenomena and their interactions required use of very high-resolution numerical weather prediction models initialized with IHOP data. These observations and the numerical modeling together offer the opportunity for an unprecedented study of the evolving structure of bores, solitons, and solitary waves.