AEOLUS+ INNOVATION – STUDIES ON WIND AND AEROSOL INFORMATION FROM LIDAR SURFACE RETURNS (SWAILS+)

In the SWAILS+ project the Aeolus lidar surface returns are used in combination with collocated wind speed observations to retrieve the aerosol optical depth. The retrieval algorithm under development, LARISSA (Lidar Aerosol Retrieval based on Information from Surface Signal of Aeolus), will complement the standard Aeolus (L2) aerosol profile products. Not only as LARISSA provides an opportunity to evaluate the standard Aeolus aerosol products but also since the L2a profile approach lacks sensitivity in low aerosol loading regions where an integrated column approach may be more successful.

In addition, for low aerosol optical depth conditions, it is investigated whether it is feasible to retrieve the:

• Near-surface winds
• Bidirectional reflectance distribution function over land, based on which aerosol optical depth over land can be also retrieved using LARISSA

The LARISSA products are developed at the Royal Institute of Meteorological Sciences (KNMI) in the SWAILS (NSO) and SWAILS+ (ESA) projects.

The resulting aerosol product from LARISSA will be beneficial for various scientific applications including

• Better understanding of the wind speed dependence in off-nadir ocean surface scattering in the ultraviolet.
• Evaluation of aerosol models, where the LARISSA-based (integrated) aerosol optical depth can be used as input for data assimilation.
• Studies of global aerosol optical properties as LARISSA will retrieve the average column lidar ratios.
• Support of future lidar missions with nadir and non-nadir viewing angles in the UV, i.e., the EarthCARE mission lidar ATLID.