Summer School on LIDAR: The laser behind atmospheric pollution

Experts in the area are presenting the physical and technological foundations of LIDAR systems, based on a transcendental technique related to the study of air pollution.

Pollution is a problem that seriously affects a large part of our planet, and that is why every day new forms and technologies are sought to measure it. Thus, new measures to mitigate it are generated, as for example, defining latent zones of pollution. LIDAR is one of the scientific techniques used to measure this problem, and it is being used more and more.

Dr. Montilla pointed out that the importance of this technique lies not only in the details that allow us to know about the evolution of atmospheric composition, but also from a social point of view, “due to the great importance that is currently placed on knowing the evolution of air pollution in these times that we are living.”

For Dr. Carlos Saavedra, Scientific Director of CEFOP, this school offers the possibility to generate very concrete possibilities of collaboration with other South American researchers in LIDAR technology, particular those from Argentina, Brazil and Colombia. “We are interested in talking with them, and discussing long-term programs, where our LIDAR laboratory is incorporated into the world-wide program of LIDAR observations in themes which they are concentrating on.”

But at the same time, Saavedra noted, “We would like for our students, at the University of Concepción and those that visit us, to have the possibility of getting to know each other and to participate in these types of activities so they can take part in future challenges. Today we have begun discussions of some complementary programs of collaboration, not only with LIDAR, but also with DOAS technology, where we will probably initiate a collaboration with Argentina, with researchers headed by Dr. Elián Wolfram.”

How to approach this technology, its implications, and its evolution is what is being developed in the V Summer School on Optics and Photonics, organized by the Center for Optics and Photonics (CEFOP) at the University of Concepcíon, financed by the Basal Program of Conicyt. Their applications are of great scientific and social relevance in the study of air pollution and its effects, explained one of their organizers, Dr. Elena Montilla, who also is a researcher at the LIDAR laboratory of CEFOP.

STRONG EVOLUTION

Dr. Elián Wolfram is one of the top specialists of the LIDAR technique in Argentina, and he is a member of the Center for Laser Research and Applications in that trans-Andean country. On his first day of Summer School, he assured us that this is a “fantastic initiative of CEFOP, because it allows for the creation of ties between communities in the Americas, especially in Latin America, which we need to reinforce.”

He added that Chile has grown considerably, and took as an example the Center for Optics and Photonics of UdeC, where he emphasized that in the capacity for experimental development, there “really is a quantum leap. Universities of excellence in the world easily carry out theoretical physics, but not experimental physics, and here we see a demonstration that the experimental part, from the application of its knowledge, has taken on an important role.”

With respect to LIDAR technology, he emphasized that it is already an important instrument for observations of phenomena with great social impact, “like the ozone layer, urban pollution or, in general, the volcanic eruptions that are currently affecting us. Thus, LIDAR is becoming a tool of almost daily use, in research groups or centers that need this information with a high degree of accuracy.”

HOW IT WORKS

Dr. Alvaro Bastidas, from the Spectroscopy Laser Group of the National University of Colombia, pointed out that the operation principle of LIDAR systems is based on sending a pulsed laser beam into the atmosphere, and in the analysis of a fraction of the radiation retro disseminated by existing atmospheric particles, throughout the optical path crossed by the short pulses of laser light. “This small amount of light that returns towards the point from which the laser shot it, is gathered by a telescope and is detected.”

Then, he continued, after a delicate and complex processing of these signals, “It is already possible to obtain valuable data on the spatial distribution of particles throughout the trajectory followed by the laser light, as well as a characterization of relevant atmospheric optical parameters associated with known atmospheric particles like aerosols.”

According to Bastidas, a LIDAR instrument works like an authentic optical radar, “whose design and practical use is concentrated on the study of atmospheric particulates, whose role in Earth energy outcomes and their implications for future climatic conditions is an important current research topic.”



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