Integrated Quadrant Analysis: A New Method for Analyzing Turbulent Coherent Structures in the Atmospheric Surface Layer

Abstract:

Integrated quadrant analysis is a novel technique to characterize the trajectory and the strength of turbulent coherent structures in the atmospheric surface layer. By integrating the three-dimensional velocity field characterized by traditional quadrant analysis with respect to time, the trajectory history of individual coherent structures can be preserved with Eulerian turbulence measurements. This technique connects a coherent ejection with the subsequent sweep and quiescent period in time to visualize and to quantify the strength and the duration of a coherent structure. We developed and verified the method of integrated quadrant analysis with data from three field studies: the Eclipse Boundary Layer Experiment in Corvallis, OR in August 2017, the Cherry Vertical Array Experiment in Linden, CA in November 2019 and the Canopy Horizontal Array Turbulence Study in Dixon, CA in the spring of 2007. Integrated quadrant analysis is a promising addition to traditional turbulence analysis techniques because it provides information about an individual coherent structure that consist of both an ejection and a sweep attached to each other in a single sequence. The integrated analysis also helps to portray an eddy trajectory in three-dimensions around a sensor, which indicates that the turbulent cross-stream velocity is usually an important momentum transport component in a coherent structure.