Datensatz

Zusammenfassung

The MAC aerosol climatology defines monthly global maps for aerosol
properties. The definition of mid-visible optical and microphysical
properties is strongly linked to multi-year statistics of observations
by sun-photometers of the AERONET and MAN ground networks. As available
statistics are spatially sparse, context from bottom-up global modelling
is added. Now in its second version, oceanic MAN reference data are
included, a different lower anthropogenic fraction is assumed and the
merging of the data-statistics is improved. Hereby, now only absolute
properties are merged and trusted photometer data are given stronger
weights via regional corrections in place of local domain limited
corrections. Global average mid-visible (550mn) aerosol properties are
0.12 for the aerosol optical depth (AOD), 0.94 for the single scattering
albedo (SSA) and 0.7 for the asymmetry-factor (ASY). Averages for
sub-micrometer (fine-mode) and super-micrometer (coarse-mode) aerosol
sizes are 0.063 (AODf) and 0.058 (AODc), 0.92 (SSAf) and 0.965 (SSAc)
and 0.64 (ASYf) and 0.77 (ASYc), respectively. A new element is the
separation of aerosol absorption (AAOD) by sky-/sun-photometers into
fine-mode and coarse-mode contributions. These properties as well as the
fine-mode effective radii were merged with background data from global
modelling yielding global averages of 0.0051 (AAODf), 0.0021 (AAODc) and
0.18 mu m (RE,f). Local monthly mode detail now allows (in a top-down'
approach) to extract global distributions for aerosol component amounts
and sizes. As the considered components for soot (BC), organics (OC),
non-absorbing fine-mode (SU), sea-salt (SS) and mineral dust (DU) have
pre-defined spectrally resolved properties, optical properties at other
than mid-visible wavelengths are automatically defined - as required in
broadband radiative transfer applications. With component information
(e.g. amount, composition and size) also MAC estimates for CCN and IN
concentrations are possible and also a simple MAC based aerosol
retrieval model for satellite sensor data is suggested.