Multi-variable turbulence characteristics of the daytime atmospheric
boundary layer over an arid region using measurements from a 200-m tall
tower
Abstract
Turbulence parameterizations (TP) in numerical weather prediction models
remains one of the challenging tasks as we lack a comprehensive
understanding on the turbulence processes under myriad weather
conditions. One way to make improvements to these TPs is through
obtaining empirical evidence of turbulence structures via exploring
multi-parameter turbulence analyses. To the best of our knowledge, we
reported here the first multi-parameter vertical profiles of turbulence
characteristics based on the analyses of higher-order moments of five
key thermodynamic variables in the lower part of the atmospheric
boundary layer (ABL) over an arid region. Observational studies
reporting turbulence features in the ABL over arid regions remain
underexplored although drylands are home to more than 38% of the
world’s population. Due to lack of adequate soil moisture, two of the
key features of land-atmosphere feedback over an arid region are strong
sensible-heat fluxes and intense turbulent-mixing. We used
high-resolution (50-Hz) measurements of 3-d wind components, moisture,
and temperature obtained at 10 vertical levels on a 200-m Tall Tower at
Reese Technology Center in Lubbock located in Texas Panhandle in the US
to explore turbulence characteristics under synoptically benign weather
conditions. To demonstrate the method, we choose a case study (18 July
2020) where we used daytime measurements obtained on the tower from
17:00-00:00 UTC (12:00-19:00 LT). We found evidence that there is an
altitude dependence on the location of the peak values of the variance
and skewness of the vertical, zonal, and meridional velocity, potential
temperature, and specific humidity.