Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

Mithu Debnath,Aditya Choukulkar,James M Wilczak,William J Shaw,Ryan Ashton,Ruben Delgado,W Alan Brewer,G Valerio Iungo,Daniel Wolfe,Julie K Lundquist

doi:10.5194/amt-10-431-2017

Abstract

Abstract. Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

Highlights

Triple RHI scans were performed to retrieve vertical profiles of the 3-D wind velocity. This test is part of the XPIA experiment, which was funded by the US Department of Energy and was carried out at the Boulder Atmospheric Observatory in Erie, Colorado, for the period 2 March–31 May 2015
RHI scans were performed simultaneously with four scanning Doppler wind lidars in order to produce two virtual towers determined by the intersections of their vertical measurement planes
Intercomparison of the triple RHI data with those obtained from the other instruments has shown that the proposed scanning strategy is highly compelling for producing vertical profiles of the horizontal wind velocity and wind direction

Summary

Introduction

Wind Light Detection and Ranging (lidar) systems have been employed for wind velocity measurements in different disciplines, such as meteorology (Banta et al, 2002; Calhoun et al, 2006; Emeis et al, 2007; Horanyi et al, 2015; Vanderwende et al, 2015; Bonin et al, 2015), aeronautic transportation (George and Yang, 2012; Smalikho and Banakh, 2015), wind engineering (Jakobsen et al, 2015) and wind energy (Aitken et al, 2012, 2014; Iungo et al, 2013a; Iungo and Porté-Agel, 2014; Banta et al, 2015; Iungo, 2016). Various measurement planes are selected in order to determine specific locations for which two lidars perform coplanar RHI scans, while a third lidar measures over a plane roughly perpendicular to the one probed by the other two lidars (Fig. 1) With this measurement procedure, at the intersection location of the three lidar measurement planes, a vertical profile of the 3-D velocity wind field is retrieved, producing the so-called virtual tower scanning technique. These measurements are highly valuable for wind turbine wake modeling and tuning of turbulence closure models For this kind of applications, co-planar and triple RHI scans allow obtaining multiple measurement points over the vertical plane of interest by using the different range gates of the pulsed lidars and achieving small sampling periods.

Experimental setup and measurement procedures

Retrieval and assessment of 3-D wind velocity from triple RHI scans

Conclusions