Sea spray aerosol and climate assessments: Model results and remotely sensed data (Invited Presentation)
Marine aerosol optical properties will also be explored using remotely sensed data obtained by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite. CALIOP-provides high resolution (~30 m) vertical profile information about different aerosol subtypes (defined as clean continental, marine, desert dust, polluted continental, polluted dust, and biomass burning), particulate depolarization ratio (or particle non-sphericity), and aerosol color ratio (the ratio of aerosol backscatter at the two wavelengths). Despite new insights into marine aerosol optical properties, past studies have shown that CALIOP underestimates AOD values over the oceans. Here we present a new method for the correction of CALIOP-derived AOD values over the ocean using the Synergized Optical Depth of Aerosols (SODA) product. It was found that due to lower sea spray lidar ratio prescribed by CALIOP the average AOD values over the ocean are underestimated by roughly 30%. In addition, our method also explains some of the physical reasons for the variability in sea spray aerosol lidar ratios over different parts of the oceans. The results of our study suggest that 1)our calculated value of the lidar ratio is consistent with past studies, 2) the CALIOP lidar ratio selection algorithm is likely biased low (our calculated median lidar ratio is ≈ 26 sr vs. 20 sr prescribed by CALIOP), and 3) the surface wind speed is an important parameter controlling sea spray aerosol lidar ratios.