Lidar Uncertainty Measurement Experiment (LUMEX) – An Overview

Coherent Doppler LIDAR (Light Detection and Ranging) has been widely used to provide measurements of several boundary layer parameters such as profiles of wind speed, wind direction, vertical velocity statistics, mixing layer heights and turbulent kinetic energy (TKE). An important aspect of providing this wide range of meteorological data is to properly characterize the uncertainty associated with these measurements. With the above intent in mind, the Lidar Uncertainty Measurement Experiment (LUMEX) was conducted at Erie, Colorado during the period June 23rd to July 13th, 2014. The major goals of this experiment were the following:

1. Characterize sampling error for vertical velocity statistics

2. Analyze sensitivities of different Doppler lidar systems

3. Compare various single and dual Doppler retrieval techniques

4. Characterize error of spatial representativeness for separation distances up to 3 km

5. Validate turbulence analysis techniques and retrievals from Doppler lidars

This experiment brought together 5 Doppler lidars, both commercial and research grade, for a period of three weeks for a comprehensive inter-comparison study. The Doppler lidars were deployed at the Boulder Atmospheric Observatory site in Erie, site of a 300 m meteorological tower. This tower was instrumented with six sonic anemometers at levels from 50 m to 300 m with 50 m vertical spacing. A brief overview of the experiment outline and deployment will be presented. Results from the sampling error analysis and its implications on scanning strategy will be discussed. Results from inter-comparison of retrieval techniques and error of spatial representativeness analysis will be presented to discuss the importance of the choice of scanning strategy and retrieval algorithm based on the application, such as boundary layer studies or wind energy.