Developing a robust, compact laser-based aerosol sensing system

Aerosols are solid and/or liquid particles suspended in the atmosphere, spanning in size from a few nanometers to tens of micrometers. Common aerosol types include dust, smoke, sea salt, and particulate vehicle exhaust. While there is growing understanding of the impacts of different aerosols, which range from being hazardous to human health to driving weather and climate processes, there is much to be learned about the relative spatial and temporal distributions of different aerosol types throughout the atmosphere. As they are highly variable in their physical and chemical properties due to their wide range of natural and human-driven sources, differences in size, shape and composition can be detected by the different ways aerosols interact with light.
Light detection and ranging (lidar) techniques are in use for example in the ACTRIS EARLINET [1] network of advanced laser measurement observatories to gather information about aerosols in the atmosphere. Backscatter and exctinction measurements at different wavelenghts and polarizations of light are used along with passive measurements and chemical transport models to assess type and amount of aerosol. However the number of these expensive stations is limited and there is a need for development of smaller, lower cost instruments to increase the measurement coverage. Figure 1 gives an example of what can be measured with one low cost laser channel. This includes verticle structure of aerosol layers, and identification of times and heights of enhanced aerosol plumes. However, from this system the type of aerosol present cannot be assessed without the adition of external information.
This project will utilize low cost laser and detector technology at a variety of wavelengths and novel optical design techniques to develop a new laser-based aerosol remote sensing instrument. This new instrument will enable broader coverage of the atmosphere anda range of new applciations thanks to its low cost and mass. To optimize the design, performance will be simulated for a variety of conditions. Later, the performance of the new instrument will be evaluated through field campaigns in Greece or Italy.