Comparison of Aerosol optical properties derived from column averaged and near surface observations at Bermuda during Spring 2009

We made continuous measurements of size segregated aerosol light scattering (with a nephelometer and absorption (using filterpad absorption) at the surface at Tudor Hill, Bermuda between January and June 2009. Along with these measurements we have a Micro-pulse lidar (MPL, operated by MPLnet) and a CIMEL automated sun-sky radiometer, operated by AERONET. These additional instruments allow us to look at the vertical distribution of aerosols (MPL) and column averaged aerosol properties (CIMEL). Several parameters, which can be derived from both sets of measurements, are compared to look at surface vs column aerosol properties. The relative contribution of submicron aerosol light scattering to total aerosol light scattering was investigated using the size segregated surface measurements, and the derived size distribution from the AERONET retrieval. The column averaged properties and surface measured properties agreed well, with a slight enhancement of the column contribution of submicron particles over the surface measurements. We also found that the single scattering albedo (SSA) measured at the surface by combining daily averages of the aerosol absorption and aerosol light scattering were in the same range as the instantaneous derived column SSA. We will also discuss the comparison of the surface measured light scattering with the vertical distribution of extinction derived from the MPL.