Climate studies to benefit from 12 years of satellite aerosol data
Aerosols, very small particles suspended in the air, play an important
role in the global climate balance and in regulating climate change.
They are one of the greatest sources of uncertainty in climate change models.
ESA's GlobAerosol project has been making the most of European satellite
capabilities to monitor them.
Using data from the Along Track Scanning Radiometer-2 on the ERS-2 satellite,
the Advanced Along Track Scanning Radiometer and the Medium Resolution Imaging
Spectrometer on Envisat and the Spinning Enhanced Visible & InfraRed Imager (SEVIRI)
instrument on the Meteosat Second Generation, GlobAerosol has produced a global
aerosol dataset going back to 1995. The full dataset is available on the
Some aerosols occur naturally, originating from sea-spray, wind-blown dust,
volcanic eruptions and biochemical emissions from oceans and forests, while
others are produced through emissions from industrial pollution, fossil-fuel
burning, man-made forest fires and agriculture.
They are important because they strongly affect Earthâ€™s energy balance in two
ways: they scatter and absorb sunlight and infrared emission from Earth's
surface, and act as condensation nuclei for the formation of cloud droplets.
According to the Intergovernmental Panel on Climate Change, these effects tend
to cool the planet to almost the same degree as carbon dioxide emissions warm
it. These estimates are uncertain, however, so more data are needed.
Satellite data can provide essential information on the global distribution
of aerosols to help understand the impact of these processes for the purposes of
predicting weather and climate as well as for monitoring the transport of
To investigate the usefulness of the dataset, pilot studies were carried out by
six atmospheric modelling groups from the European Centre for Medium-Range
Weather Forecasts, the Laboratoire des Sciences du Climat et l'Environnement,
the University of Leeds, the University of Edinburgh, the Max Planck Institute
for Meteorology, and the Netherlands Organisation for Applied Scientific
Research (TNO). Comparing the satellite data with the model predictions showed
differences that helped to highlight deficiencies in both.
Results of the pilot studies were presented during ESAâ€™s Atmospheric Science
Conference held in Barcelona, Spain, in September. Maria Grazia Frontoso,
working on the development of the GLOMAP aerosol model at the University of
Leeds in the UK said: "GlobAerosol seems to be a very useful tool to address
uncertainties in global models."
Arjo Segers from TNO in the Netherlands compared GlobAerosol data with model
predictions of desert dust and forest fires over the Iberian peninsular. "The
results of this study suggest that the GlobAerosol SEVIRI dataset is especially
useful for investigating aerosol levels over water."
Still, more work is needed to address the problems highlighted in the
intercomparison study of the models, and to improve the overall accuracy of the
satellite aerosol data. The valuable feedback obtained from the users will help
to lay the foundation for the development of more accurate satellite-based
aerosol measurements as part of ESAâ€™s new Climate Change Initiative.
The GlobAerosol project was carried out by GMV (Spain), the University of
Oxford (UK), Rutherford Appleton Laboratory (UK) and Laboratoire Optique
Atmospherique (France) and funded by the Data User Element under ESAâ€™s Earth
Observation Envelope Programme.