Global scale lidar ratio retrieval over the ocean
Résumé
In this paper we discuss global scale lidar ratio retrieval over the ocean as derived by the Synergized Optical Depth of Aerosols (SODA) algorithm (based on CALIPSO/CloudSat ocean surface echo) and comparisons with CALIOP V3 lidar ratio for marine aerosols, dusts and cirrus clouds. As expected, the signatures vary as a function of the feature type. We show that the SODA lidar ratio at 532 nm is in relatively good agreement with what is currently used in CALIOP operational product. The lidar ratio at 1064 nm is however different. The origin of the differences cannot as yet be clearly identified. It may be related to the 1064 nm calibration, the ocean surface product, or to residual errors in the identification of aerosol type. As the lidar ratio is linked to the aerosol absorption and the backscatter phase function, it will help to better understand the aerosol and cloud radiative properties at global scale in the visible and in the near infrared.