Space-based lidar characterization of atmospheric boundary layer aerosols

Artificial and natural atmospheric boundary layer (ABL) aerosols affect optical and infrared earth observation from space and they play a determinant and yet unresolved role in global climate by acting on the earth radiation balance. They also control to some extent the formation of fog, clouds and precipitation. Better knowledge of their optical and physical properties is needed to resolve these issues. Because of the small size (large scattering angle) and relatively low extinction values (large mean free path) of these aerosols at visible and near infrared wavelengths, ground-based lidar measurements are not significantly affected by multiple scattering, even at wide (similar to10 mrad) fields of view (FOV). However, the same characteristics make them suitable for multiple-field-of-view (MFOV) lidar sounding from space. Indeed, the scattering angle and the lidar FOV are well matched, as well as the scattering mean free path and propagation distances. We propose here that space-borne MFOV lidar could be an effective tool for studying the global distribution of ABL aerosols.