-> Aerosol Comparisons between Observations and Models



The joint initiative AEROCOM shall document and understand the differences apparent in current global aerosol models. It seeks answers to key modeling questions, such as consequences of differences in

  • source strength
  • vertical transport or removal
  • water uptake
  • aerosol composition
  • aerosol size
  • broadband radiative transfer

on the overall quality of the aerosol simulation and estimates of the direct radiative effect of the aerosol.

The project shall make use of new remote sensing measurements of aerosol from ground and space. Satellite data will be applied to investigate to what extent patterns of global aerosol distributions are correctly represented in aerosol models. Ground statistics will be applied to provide quantitative references in terms of composition, size, concentration and altitude. To address not only regional but also seasonal differences, those measurements and models shall be used which cover at least an entire year. For comparability models shall be forced by analyzed meteorology. Regional models shall be included, if they can fit in the output framework set for this global model intercomparison.

The range of model results documented with AEROCOM shall help to establish and reduce the uncertainty in aerosol climate forcing estimates.

More specifically, AEROCOM shall document and intercompare among models and to available measurements for a given year on a seasonal and regional basis

  • Near surface winds (critical for the production of for natural aerosol)
  • Parameterization schemes in aerosol processing
  • Diffusive properties of the transport model
  • Mass (balances) for each aerosol type (dust, seasalt, sulfate, bc, org.matter)
  • Mass compositional mix
  • Humidification and water uptake for each aerosol species
  • Assumptions on size and refractive index
  • Optical depth (balances) for each aerosol type
  • Optical depth compositional mix
  • Assumptions in the broadband radiative transfer scheme

Aerocom also aims to provide

  • Control simulations with prescribed sources
  • Control simulations with prescribed ambient rel.humidity for swelling
  • Reduced output at times of model-scale ‘cloud-free’ satellite observations
  • Simulations at different spatial resolutions

is an international
science initiative
on aerosols and climate

supported by
EU Framework programmes

Norw. Met Office
Max-Planck Ges.
French CNES