Optical properties of the marine atmospheric boundary layer: aerosol profiles

Abstract

The distribution of aerosols in the marine boundary layer can be viewed as a dynamic balance of production, transport, and removal processes. the balance of these processes can be represented by a single mixed-layer model. The vertical distribution of aerosols is dominated by turbulent transport. When mixing is dominated by surface shear or cloudtop cooling (as is typical in mid-latitudes), a single "well-mixed" layer is sufficient to describe the aerosol profile. When scattered cumulus clouds are present (called the "trade wind" or "weak cumulus convection" regime), the well-mixed layer is confined to the region below cloud base. In the region above cloudbase and below cloudtops, strong vertical gradients of aerosol concentration may be observed. A simple parameterization of this gradient is presented.