Abstract
We examine the potential importance of wind-directional shear in the surface layer of the stable nocturnal boundary layer by analyzing two tower datasets with eddy-correlation measurements at multiple levels. Directional shear is a major contributor to the total vector shear for weak winds due primarily to frequent shallow drainage flows at one site and due primarily to non-stationary modes at the second site. For weak winds, the turbulence intensity is more related to the wind-directional shear than to the wind speed or stratification, at least for these two datasets.
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Acknowledgements
The important comments of Danijel Belušić and Jielun Sun are greatly appreciated. This project received support from AGS-1614345 from the National Science Foundation. The measurements for the SCP and FLOSSII field programs were provided by the Integrated Surface Flux System of the Earth Observing Laboratory of the National Center for Atmospheric Research.
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Mahrt, L. Directional Shear in the Nocturnal Atmospheric Surface Layer. Boundary-Layer Meteorol 165, 1–7 (2017). https://doi.org/10.1007/s10546-017-0270-1
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DOI: https://doi.org/10.1007/s10546-017-0270-1