DOI: 10.5068/d1tx0t
title: Data from: Turbulence organization and mean profile shapes in the stably stratified boundary layer: Zones of uniform momentum and air temperature

description: A persistent spatial organization of eddies is identified in the lowest
 portion of the stably-stratified planetary boundary layer. The analysis
 uses flow realizations from published large-eddy simulations (Sullivan et
 al., J Atmos Sci 73(4):1815–1840, 2016) ranging in stability from
 near-neutral to almost z-less stratification. The coherent turbulent
 structure is well approximated as a series of uniform momentum zones
 (UMZs) and uniform temperature zones (UTZs) separated by thin layers of
 intense gradients that are significantly greater than the mean. This
 pattern yields stairstep-like instantaneous flow profiles whose shape is
 distinct from the mean profiles that emerge from long-term averaging.
 However, the scaling of the stairstep organization is closely related to
 the resulting mean profiles. The differences in velocity and temperature
 across the thin gradient layers remain proportional to the surface
 momentum and heat flux conditions regardless of stratification. The
 vertical thickness of UMZs and UTZs is proportional to height above the
 surface for near-neutral and weak stratification, but becomes thinner and
 less dependent on height as the stability increases. Deviations from the
 logarithmic mean profiles for velocity and temperature observed under
 neutral conditions are therefore predominately due to the reduction in
 zone size with increasing stratification, which is empirically captured by
 existing Monin-Obukhov similarity relations for momentum and heat. The
 zone properties are additionally used to explain trends in the turbulent
 Prandtl number, thus providing a connection between the eddy organization,
 mean profiles, and turbulent diffusivity in stably stratified conditions.
description: The dataset is a collection of post-processing results based on
 large-eddy simulations (LES) of the planetary boundary layer.  The
 simulations include a neutrally-stratified case and four stably-stratified
 cases with different surface cooling rates. Additional details of the LES
 are given elsewhere (Sullivan et al., J Atmos Sci 73(4):1815–1840, 2016).
 The dataset includes statistics for zones of uniform momentum and air
 temperature detected from instantaneous realizations of the turbulent LES
 flow volumes. Also included are sample scripts for detecting uniform zones
 from flow volumes and computing the zone statistics. The scripts adhere to
 the detection methodology and processing discussed in the related
 article.
description: The data comprise processed statistics corresponding to the
 published results of the study. These include average LES quantities and
 properties of detected uniform turbulent zones. The data are organized as
 tab-separated values in text files, where the header rows provide relevant
 information. The figure number in each file name refers to the
 corresponding figure in the related article. The sample
 post-processing scripts are written in Matlab format. The scripts can be
 viewed using any text editing program, but can only be executed using
 Matlab software that includes the signal processing and statistics
 toolboxes.