We conducted a large eddy simulation of the stable boundary layer in order to investigate the coherent structure of the Kelvin–Helmholtz instability (KHI). The simulations were performed using the initial conditions based on the Beaufort Sea Arctic Stratus Experiment. We used the Richardson criteria and the linear stability analysis methods to detect the KHI and to adopt the eigenvalue and the two-point correlation methods to identify the vortex cores near the KHI region. In the two-point correlation analysis, the rotating configuration of the KHI varied in angles and lengths, according to the difference in the distance to the inversion layer. These vortex cores were divided into four components in different directions, defined by the signs of the x and y vorticities (Wx and Wy, respectively), and the vortex cores of the two components related to the negative Wy were elongated along the streamwise direction. The ratio between the sweeps and the ejections exhibited a linear trend as the boundary layer became more stable. Also, the sweep motion was dominant to the ejection motion for a high-stability index of 1.63. Furthermore, the plot of the vortex angles versus the stability index illustrated a linear relationship, indicating that the varying trends of the vortex angles were independent from the distance to the inversion layer in a sensitivity study of the vortex angle.
Bibliographical noteFunding Information:
Acknowledgments This research was funded by the Korea Meteorological Administration and conducted by Korea Institute of Atmospheric Predictions Systems. Supercomputing resources, including technical support (KSC-2012-C2-24), were provided by the National Institute of Supercomputing and Networking/Korea Institute of Science and Technology Information. This work was also supported by a grant from the Midcareer Researcher Program of the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT, and Future Planning (grant NRF-2013R1A2A2A01015333). This work was also supported by Business (grants C0151226) in 2014 for Cooperative R&D between Industry, Academy, and Research Institute funded by Korea Small and Medium Business Administration.
© 2014. American Geophysical Union. All rights reserved.
All Science Journal Classification (ASJC) codes
- Aquatic Science
- Water Science and Technology
- Soil Science
- Geochemistry and Petrology
- Earth-Surface Processes
- Atmospheric Science
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science