Dynamic calibration method for the system constant of high-spectral-resolution lidar with airborne experimental verification

High-spectral-resolution lidar (HSRL) provides vertically resolved aerosol optical properties, but its retrieval accuracy depends critically on the calibration of the system constant, which can vary with time, especially under airborne observation conditions. In this study, a time-varying effective system response factor is proposed for measurement-state diagnosis and dynamic calibration of airborne HSRL. Ground-based observations on a stationary platform are used as a reference to characterize the system response under stable conditions, while airborne observations using the same lidar system on a flight platform are used to investigate the additional effects of platform disturbances. The results show that the calibration coefficient is not strictly constant even under ground-based conditions, whereas airborne observations exhibit stronger temporal fluctuations. Event-based analysis of this single flight dataset indicates that 62% of significant effective system response factor variations during this airborne observation are synchronized with platform disturbances, with roll-angle variation identified as the most frequently associated disturbance indicator under this flight condition. After applying the dynamic calibration approach, the mean relative errors of the attenuated backscatter signals in both the parallel polarization channel and the high-spectral-resolution channel are reduced to less than 10%, while the total uncertainties are below 5.5%. This method provides a framework for high-precision dynamic calibration of HSRL systems under complex observation conditions.