Intercomparison of Calibration techniques for the 1064nm channel on a Nd:YAG elastic lidar

The need for accurate calibration is apparent for accurate retrievals of backscatter at 1064 nm. Due to the low molecular scattering in comparison to the aerosol component, it is not possible to use a Rayleigh calibration procedure which is suitable for the 355 and 532 nm channels and an alternative approach is needed. In particular, a modified cirrus cloud calibration method is considered which uses the fact that the cirrus cloud scatter is spectrally independent together with an approach to properly estimate the backscatter at cloud base. We find that the calibration accuracy can be taken within 15% which is reasonable agreement with the uncertainly in the backscatter color ratio between 532 nm and 1064 nm.