A preliminary examination of wind farm effects on the atmospheric boundary layer during the American WAKE ExperimeNt

Wind farms are attractive renewable energy solutions that provide an eco-friendly alternative to burning fossil fuels. As wind farms grow in size and numbers throughout the world, their impact on the regional climate has become a topic of interest. They are hypothesized to impact meteorological processes in the planetary boundary layer (PBL), the lowest 2-km of the atmosphere. Recently, deployment commenced for the American Wake Experiment (AWAKEN), a field campaign tailored to study the effects of wind farms on the PBL in Northern Oklahoma. Among several measurement methods to collect AWAKEN data, two Collaborative Lower Atmospheric Mobile Profiling System (CLAMPS) platforms, which contain a Doppler wind lidar and two thermodynamic profiling instruments, were placed in the vicinity of two wind farms (CLAMPS1) and outside the influence of the farms (CLAMPS2) to compare PBL processes. Though data collection and analysis is currently still ongoing, data from the two CLAMPS sc  anning Doppler lidars can be used to illustrate the variability of wind speed, wind direction, and turbulence in the AWAKEN domain. Here, a single case of time-height profiles of these variables from CLAMPS1 are compared to that of CLAMPS2 to examine the differences between sites with and without wind farms.

One goal of AWAKEN is to understand how detecting the top of the boundary layer is affected. Height detection analysis has previously been accomplished outside of wind-farm terrain using data from the 2021 Boundary Layer Integrated Sensing and Simulation Field Universalization Laboratory (BLISSFUL) field campaign in Central Oklahoma. The height detection findings of a BLISSFUL case of similar meteorological conditions to the CLAMPS2 AWAKEN case are presented to decipher results that can be expected from an environment devoid of wind farms. This is then used to hypothesize height detection results from CLAMPS1 time-height profiles, an environment that does contain wind farms. Based on the test cases from BLISSFUL and AWAKEN, the overnight turbulent mixing is stronger at the CLAMPS1 site and the turbulent layer near the end of the day is deeper than at the CLAMPS2 site. This deeper PBL could increase the PBL height estimation from a detection method dependent on the vertical velocity  data, such as fuzzy logic. This will be further investigated along with convection, nocturnal-low-level jets, and PBL transitional periods as the AWAKEN campaign continues through the end of 2022.