Atmospheric aerosol particles affect the atmosphere’s radiation balance by scattering and absorbing sunlight. Moreover, the particles act as condensation nuclei for clouds and affect their reflectivity. In addition, aerosols have negative health effects and they reduce visibility. Aerosols are emitted into the atmosphere from both natural and anthropogenic sources. Different types of aerosols have different effects on the radiation balance, thus global monitoring and typing aerosols is of vital importance. Tropospheric aerosol imposes one of the least understood impacts on the Earth’s climate. It is difficult to define characteristic aerosol properties. Yet they are needed at high accuracy on global and seasonal scales to create confidence in model derived predictions on the aerosol climatic impact and the climate change attributed to anthropogenic aerosol.

The characterization of aerosol concentration and aerosol properties in these models is highly parameterized and frequently far from reality. Some of the aerosol information in these models due to their need for global coverage is based on satellite data. These data by themselves carry significant uncertainties.

It is our goal to validate critical aerosol assumptions in models or satellite retrievals requiring ground-based monitoring. Cimel develops several active and passive remote sensing solutions used in the measurement of atmospheric aerosols. Passive instruments measure radiation emitted by the sun and the Earth while active instruments have their own radiation source (laser).