Advanced Calibration Framework for 3-D Scanning Doppler Wind Lidar: Enhancing Performance and Measurement Accuracy

Abstract

This study presents a unified calibration and performance assessment framework for 3-D scanning Doppler wind lidar (3-D DWL), combining plan position indicator (PPI) scanning with a dual-validation strategy based on cosine fitting and discrete Fourier transform (DFT) analysis; a high-precision rotating flywheel is employed to provide a bench reference for line-of-sight (LOS) velocity calibration and to eliminate systematic instrumental biases. Under strong-signal conditions, the LOS standard deviation is as low as 0.06 m·s−1, and the divergence between the two retrievals provides an objective, atmosphere-adaptive determination of the effective measurement range (approximately 4.8 km slant range, with data availability above <inline-formula> <tex-math notation="LaTeX">$90~\%$ </tex-math></inline-formula> to about 4.6 km slant range, i.e., 4.4 km altitude). In two spring intercomparison campaigns against operational radiosonde station 54511 (2025 and 2026; 83 soundings; winds up to 33 m·s−1), the retrieved wind speed agrees with the radiosonde with a coefficient of determination <inline-formula> <tex-math notation="LaTeX">$R^{2}=0.94$ </tex-math></inline-formula> and a mean absolute error (MAE) of about 0.94 m·s−1, and the wind direction with an MAE of about 9° (<inline-formula> <tex-math notation="LaTeX">$R^{2}=0.99$ </tex-math></inline-formula> after correcting the 0°/360° wrap around). The two collocated lidars mutually agree with <inline-formula> <tex-math notation="LaTeX">$R^{2}=0.99$ </tex-math></inline-formula>, and a triple-collocation analysis separates the noncommon (unit-to-unit) lidar random error, which is several times smaller than the representativeness term of the comparison and is a lower bound on the absolute single-unit error. These results support the application of the framework to wind energy assessment, aviation safety, and meteorological research.