Diode-Laser-Based Direct-Detection Doppler Wind Lidar: Initial Results

This presentation details the development and initial performance of a novel diode-laser-based direct-detection Doppler wind lidar (DWL) instrument. The DWL leverages the MicroPulse DIAL (MPD) instrument architecture, which has demonstrated robust, long-term field operation. Previous MPD instruments have successfully employed differential absorption lidar (DIAL) techniques for profiling water vapor and temperature and the high spectral resolution lidar (HSRL) technique for profiling calibrated aerosol backscatter. In this work, we extend these capabilities to include profiling radial wind speed using a similar instrument configuration.

Our DWL system combines an MPD transmitter operating at 770 and 780 nm, a double-edge DWL receiver at 780 nm, and a potassium vapor HSRL receiver at 770 nm. This configuration allows for simultaneous profiling of radial wind speed and calibrated aerosol backscatter in the lower atmosphere where aerosol concentrations are highly variable. Notably, the radial wind speed retrieval does not rely on the presence of aerosols like heterodyne DWLs, and neither is the signal corrupted by the presence of aerosols like many direct-detection DWLs, making it effective in regions with both high and low aerosol concentrations.

A laboratory prototype of this instrument has been constructed, and testing is underway. The prototype demonstrates a cost-effective and eye-safe method for measuring radial wind speeds in the lower free troposphere, where aerosols are too sparse for wind retrievals with commercially available heterodyne DWLs. Furthermore, its design is compatible with the thermodynamic-profiling MPDs, suggesting the possibility of future instruments that could profile both thermodynamic and kinematic parameters from the same volume of air.

This presentation will provide an overview of the instrument design and demonstrate its capabilities and performance based on the initial laboratory-based measurements.