Objectives
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
