In this keynote presentation, Mark Kelly will give an overview of concepts, methods, and data characterizing the atmospheric boundary layer [ABL] which are relevant to outdoor sound propagation. Aiming to link theory with application and practice, the focus will primarily be on the ABL. This is due in part to the quite thorough descriptions of outdoor sound propagation and associated statistics given in the book by Ostashev & Wilson (2016), as well as a number of review presentations and advances since its publication (in addition to my primary work for the past 2 decades being in theoretical and applied ABL meteorology).

A brief review of the parallel recent histories of outdoor sound propagation and applied ABL meteorology will be given, within the context of the evolution of the state of the art regarding measured and modelled statistics; as the science has developed, a move from first to second-order predictions has occurred. This includes uncertainty quantification, driven by the sensitivity of outdoor propagation modelling to atmospheric parameters, along with statistical representativity issues unique to the ABL that are not commonly understood in applied acoustics and other applications (e.g., my current area of wind energy). Dimensionless metrics pertaining to characterization of the ABL state, and issues incurred around their neglect or sampling, as well as associated atmospheric modelling, will be discussed.

The types of relevant atmospheric models which give data that can inform outdoor propagation calculations, from global to weather to computational fluid dynamics, will be reviewed; this will also include emphasis on the limitations of these models and their outputs, as well as how to get needed atmospheric parameters or data. This will also be complemented by a statistical view of such models and data, towards use in different acoustics applications; a bit on noise standards arises here, too.
Some relevant aspects of atmospheric flow that are not (yet) typically addressed by outdoor propagation modelling, including recent advances, will be introduced (e.g., wind veer). What we don’t know quite well yet in the ABL—i.e., the “edge” of the state-of-the-art—will also be discussed. Lastly, consideration will be given to variation in practical application, not only in terms of the calculations and data, but beyond engineering and modelling, linking to the psychosocial aspect such as community acceptance.

Mark Kelly

Danish Technical University

Appearances