Daytime Evolution of Lower Atmospheric Boundary Layer Structure: Comparative Observations between a 307-m Meteorological Tower and a Rotary-Wing UAV

Abstract

A 307-m tall meteorological tower was used to evaluate meteorological observation data obtained using a rotary-wing unmanned aerial vehicle (UAV). A comparative study between the tower and UAV observations was conducted during the daytime (06:00 to 19:00 local time (LT)) in the summer of 2017 (16–18thAugust). Hourly vertical profiles of air temperature, relative humidity, black carbon (BC), and ozone (O3) concentrations were obtained for up to 300 m height. Statistical metrics for evaluating the accuracy of UAV observations against the tower observation showed positive (potential temperature) and negative (relative humidity) biases, which were within acceptable ranges. The daytime evolution of the lower atmospheric boundary layer (ABL) was successfully captured by the hourly UAV observations. During the early morning, a large vertical slope of potential temperature was observed between 100 and 140 m, corresponding to the stable ABL height. The large vertical slope coincided with the large differences in BC and O3 concentrations between altitudes below and above the height. The transition from stable to convective ABL was observed at 10–11 LT, indicated by the ABL height higher than 300 m in the convective ABL. Finally, we provide several recommendations to reduce uncertainties of UAV observation.

Vertical distribution of black carbon and its mixing state in urban boundary layer in summer

“…UAVs have the advantages of high flexibility, but large precise instruments cannot be loaded by UAVs due to their low carrying capacity. UAV measurements generally focus on mass concentrations by using light instruments or sensors (Liu et al, 2020a;Lu et al, 2020;Pikridas et al, 2019;Kwak et al, 2020). Aircraft is another vertical measurement approach that combines flexibility and preciseness.…”

Turbulent Characteristics in Complex Coastal Areas Assessed Using Bswo Observations and WRF-LES Simulation Results

“…Ribeiro et al (2018) pointed out the importance of understanding the impact of atmospheric circulation on the urban environment using radiosonde profile data and three tall meteorological tower observations combined with model simulations. The Boseong Standard Weather Observatory (BSWO) was established in Korea, and it includes various in situ instruments that enable the collection of turbulence flux and atmospheric variables, including a 307 m tall tower (Kwak et al, 2020). High-quality research on turbulence and boundary layers is possible using data obtained from the BSWO.…”