Physics of Fluids - Publications

Vertical structure of conventionally neutral atmospheric boundary layers

Open Access
Proceedings of the National Academy of Sciences 119, e2119369119 (2022)

Authors

	Luoqin Liu
	Richard Stevens

BibTeΧ

@article{
doi:10.1073/pnas.2119369119,
author = {Luoqin Liu  and Richard J. A. M. Stevens },
title = {Vertical structure of conventionally neutral atmospheric boundary layers},
journal = {Proceedings of the National Academy of Sciences},
volume = {119},
number = {22},
pages = {e2119369119},
year = {2022},
doi = {10.1073/pnas.2119369119},
URL = {https://www.pnas.org/doi/abs/10.1073/pnas.2119369119},
eprint = {https://www.pnas.org/doi/pdf/10.1073/pnas.2119369119},
abstract = {The presented model describes the vertical structure of conventionally neutral atmospheric boundary layers. Due to the complicated interplay between buoyancy, shear, and Coriolis effects, analytical descriptions have been limited to the mean wind speed. We introduce an analytical approach based on the Ekman equations and the basis function of the universal potential temperature flux profile that allows one to describe the wind and turbulent shear stress profiles and hence capture features like the wind veer profile. The analytical profiles are validated against high-fidelity large-eddy simulations and atmospheric measurements. Our findings contribute to the scientific community‚Äôs fundamental understanding of atmospheric turbulence with direct relevance for weather forecasting, climate modeling, and wind energy applications. Conventionally neutral atmospheric boundary layers (ABLs) are frequently encountered in nature, and their flow dynamics affect the transfer of momentum, heat, and humidity in the atmosphere. Therefore, insight into the flow structure in conventionally neutral ABLs is necessary to further improve models for long-term weather and climate forecast, while it provides further insight for atmospheric applications like the wind industry. The structure of conventionally neutral ABLs is complicated due to the coexistence of shear- and buoyancy-generated turbulence, and therefore analytical descriptions have been limited to the mean wind speed. Here we introduce an innovative model based on the Ekman equations and the basis function of the universal potential temperature flux profile that allows one to describe the vertical profiles of the horizontal components of wind and shear stress and hence capture features like the wind veer profile. Our formulation in terms of departure from the geostrophic wind allows us to describe the profiles as a function of one control parameter, although the description of wind speed profile still needs two. We find excellent agreement between analytical predictions, high-fidelity simulations, and field measurement campaigns. These findings advance the fundamental understanding of the ABL structures and atmospheric turbulence.}}