High-resolution vertical profiles of temperature, wind speed, and turbulence during CASES-99 and their relationship to the top of the nighttime boundary layer

During the CASES-99 Campaign in east-central Kansas, the CIRES Tethered Lifting System (TLS) of the University of Colorado made some forty high-resolution vertical profiles of temperature, wind speed, and turbulence intensity. Analysis of these nighttime profiles provide considerable insight into the relationship between the top of the mixing layer height (MH), the height of zero-wind shear, and the height of maximum potential temperature gradient. We describe a number of distinctly different examples of nighttime boundary layer (NBL) structures under a variety of atmospheric conditions. Examples include very shallow NBLs, possible “double” NBLs, and an example of a so-called “upside down” boundary layer, where turbulence aloft to ~ 170 m altitude is generated entirely by wind shear, and where the surface turbulence is prevented from diffusing upward by an extremely stable inversion at ~40 m.