Life on Earth is affected by aerosols in different ways. They play an important role in the climate system; the effect of aerosols on the global climate system is one of the major uncertainties of present climate predictions. They play a major role in atmospheric chemistry and hence affect the concentrations of other potentially harmful atmospheric constituents, e.g. ozone. They are an important controlling factor for the radiation budget, in particular in the UV-B part of the spectrum. At ground level, they can be harmful, even toxic, to man, animals, and plants. Because of these adverse effects that aerosols can have on human life, it is necessary to achieve an advanced understanding of the processes that generate, redistribute, and remove aerosols in the atmosphere. A quantitative data set describing the aerosol vertical, horizontal, and temporal distribution, including its variability on a continental scale, is necessary. No suitable data set for this purpose presently exists. in this framework, ALS instruments match exactly these needs, e. g. being a part of a Lidar network thanks to its autonomous unattended capabilities, in order to store data measurement on cirrus clouds frequency and altitude, aerosol densities, planetary boundary layer height, temporal evolution and particle asphericity detection thanks to its depolarization channel.
Transcontinental aerosol transport
Aerosols may have a greater impact on patterns of overall rainfall and future climate change than previously thought. For example, the extensive pollution haze from Asia may be re-shaping rainfall patterns in Northern Australia. Recent climate modelling shows that there may be important effects on Southern hemisphere climate due to aerosol pollution from the Northern Hemisphere. These include an increase of rainfall in certain areas, and an increase of air pressure over others, which may have contributed to less rainfall there. ALS can measure and detect different aerosol layers and post-treatment using the backscattering trajectories enable to identify the original pollution source causing major climate changes.
Clouds and Aerosols properties
Aerosols influence climate through different pathways, directly on the scattering and absorption of radiation, and indirectly on the processes of cloud formation and microphysics. Monitoring the global distribution of aerosols is required to better understand the Earth climate changes, especially in order to slow the global warming and controlling the emissions of light-absorbing particles. For this reason, ALS is a ground-based optical remote sensing instrument designed to determine the vertical and horizontal properties of the atmosphere because a bigger concentration in aerosol will be evident as an increase or spike in the back-scattered signal profile, since, for example, the water droplets that make up the cloud will produce a lot of backscatter.