A065-0006
Friction velocity estimation in Coastal Sites using 2D velocity measurements
Wednesday, 9 December 2020
Poster
Bernardo Figueroa Espinoza, National Autonomous University of Mexico, Institute of Engineering, Ciudad DE Armería, Mexico, Zulia Mayari Sanchez-Mejia, Instituto Tecnológico de Sonora, Departamento de Ciencias del Agua y Medio Ambiente, Ciudad Obregón, SO, Mexico, Jorge Uuh-Sonda, Universidad Nacional Autonoma de Mexico, Instituto de Ingeniería, Mexico City, Mexico, Paulo Salles, Universidad Nacional Autónoma de México, Institute of Engineering, Sisal, Mexico, Luis A Méndez-Barroso, Sonora Institute of Technology, Sonora, Mexico and Hugo Alberto Gutierrez-Jurado, University of Texas at El Paso, Geological Sciences, El Paso, TX, United States
Abstract:
Friction velocity can be estimated using many well-known methods such as the Eddy Covariance (EC), which requires the use of a 3D high acquisition frequency anemometer. Other methods are available, but the presence of roughness inhomogeneity, sea breezes (that make the friction velocity direction dependent) or non-neutral stability conditions make the estimation a challenging task. Since many modern high-quality meteorological stations are already equipped with a 2D sonic anemometer capable of measuring in high frequency, and are considerably less expensive than a 3D anemometer, a method to estimate friction velocity from 2D data would be desirable.
A methodology based on a simple expression, cast in terms of the dimensionless mean and variance of the streamwise velocity is proposed. This method allows estimating the friction velocity using information from a 2D sonic (or other) anemometer at high frequency (10 Hz). The method was tested using experimental data from six different Coastal Sites: four in Mexico (two at the Gulf of Baja California, two at the Yucatan Peninsula) and two sites at the NE ad SW corners of Australia, comprising a variety of land covers, influence of breezes and atmospheric stability conditions. The method showed very good agreement with the friction velocity from the EC method in all cases. The method can be implemented using 2D anemometers as a post-processing routine or incorporated in meteorological stations through a suitable software update, allowing for an affordable estimation of friction velocity for many research groups. The possibility of obtaining friction velocity through this method could have an impact in countries where research funding is scarce or difficult to obtain.
