Collaborative Research: Theoretical and observational investigations of multi-point Monin-Obukhov similarity in the convective atmospheric surface layer

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This project investigates the atmospheric boundary layer (ABL)---the lowest portion of the atmosphere (approximately 1-2 km in height during daytime). Turbulence, which is responsible for commonly experienced bumpy flights, has an enormous impact on human activities and the environment. The prevailing theory of the turbulence in the ABL---the Monin-Obukhov similarity theory (MOST), while successful in many respects, has some major shortcomings. Its most glaring issue is its inability to predict large-scale wind fluctuations near the ground, which negatively impact many atmospheric applications. Dr. Tong on this proposed project has recently developed a new theory, the multi-point Monin-Obukhov similarity theory (MMO), to overcome shortcomings of MOST. In this project the researchers will further develop the theory and conduct a field campaign to systematically verify it. An improved understanding and prediction of the ABL turbulence provided by MMO can have wide-ranging implications for developing predictive models for weather forecasting, air pollution, atmospheric chemistry, and wind energy. The project will provide opportunities for a postdoctoral researcher and graduate and undergraduate students to participate in all aspects of the project. In addition, in collaboration with scientists and engineers from the National Center for Atmospheric Research (NCAR) responsible for deploying a suite of research instruments, the research team will host field trips for K-12 students at the field campaign site near Kettleman City, CA, to demonstrate how turbulence and other meteorological variables are measured. The researchers will further develop comprehensive first-principles-based predictions of the similarity properties of the daytime ABL to account for the influences of observed ABL conditions and to understand the underlying physics. A field campaign will be carried out in collaboration with NCAR to make comprehensive measurements of the mean velocity and temperature profiles throughout the depth of the boundary layer and the turbulence spectra in the surface layer. A suite of instruments including a sonic anemometer array, three Doppler lidars, an aerosol lidar, a micro-pulse lidar, a distributed temperature measurement system, a radio acoustic sounding system, a quadcoptor temperature system, and radiosondes will be used in the measurements. For each statistic, multiple instruments will be used, with each instrument covering a different height range or a scale range to achieve the overall height and scale ranges needed. The field data will then be used to systematically verify the scaling prediction and establish the (expansion) coefficients in the theory and the functional forms of the MMO similarity functions for turbulence spectra and mean profiles.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.