Multi-wavelength LILAS LiDAR Raman at the Laboratory of Atmospheric Optic (LOA).

Keywords : Aerosols, LiDARs, MicroLiDARs, monitoring, Earth observation, remote sensing, Raman, wavelengths, ash, dust, sand.

July 29th 2022

The Laboratoire d’optique atmosphérique (LOA) is a joint research unit of the National Center for Scientific Research (CNRS) of France and the University of Lille – Sciences and Technologies. The LOA studies the different components of the atmosphere, mainly clouds, aerosols and gas. In collaboration with the LOA, CIMEL created a joint research laboratory : AGORA-LAB.

Since 2005, the LOA has started the systematic observation of aerosols by LiDAR and has developed a database and an automated real-time data processing system. Its collaboration with CIMEL allowed the creation of the multi-wavelength LILAS LiDAR which was integrated into the European network EARLINET/ACTRIS in 2015.

The LILAS LiDAR was specifically designed and adjusted by CIMEL to meet a specific need of the LOA. The transportable multi-wavelength Raman research LiDAR LILAS offers a significant qualitative and quantitative value on aerosol parameters measured at night and during the day, in particular through its combination with CIMEL sun/sky/lunar photometers.

LILAS also allows the observation of clouds and the obtention water vapor and methane profiles. It also gives access to essential climate variables such as the absorption profile of atmospheric aerosols. Its maximum range can reach 20 km and allows it to study the lower stratosphere which can be useful in case of major volcanic eruption for example.

For the Data treatment, the AUSTRAL (AUtomated Server for the TReatment of Atmospheric Lidars) web server data is the processing tool, which provides real-time quicklooks of the LiDAR Range Corrected Signals (RCS) and Volume Depolarization Ratio (VDR) as well as Klett inversion results (extinction and backscatter coefficient profiles).

To answer the need of various stakeholders, the CE710 LiDAR is a fully customizable high power multi-channel aerosols LiDAR resulting from the collaboration between the LOA, CIMEL and Dr. Igor Veselovskii institute. Depending on the requirements and budgets of each, it exists multiple options to customize the LiDAR. For exemple, the choice of the laser type and the wavelengths, the depolarization options or the Raman options (and many more).

Thanks to its precision in the detection of aerosols, the LILAS CE710 LiDAR has highlighted many atmospheric natural events such as volcanic eruptions (ash) or dust and sand events for example but also biomass burning particles coming from fires. LILAS data and all the LiDAR’s activities between the LOA and CIMEL bring a precious monitoring tool to understand atmospheric phenomenas over France, Europe and worldwide.

Figure 1 : View of LILAS (telescope, laser, and acquisition bay) in vertical view, open roof hatch and example of observed aerosol profiles. LILAS is a transportable multi-wavelength Elastic & Raman LiDAR. It has 3 elastic channels (355, 532 and 1064 nm), 3 Raman channels (387, 407 and 530 nm) and 3 depolarized channels (355, 532 and 1064 nm).

Figure 2: Night time LILAS operation during SHADOW-2 campaign in Senegal (Credits: Q. Hu, LOA)

Figure 3 : Detection of smoke particles injected up to 17 km into the stratosphere by intense pyro-convection generated by the Canadian wildfires of summer 2017 (Hu et al., 2018).

Figure 4: Illustration of the extreme event in October 2017. LiDAR LILAS time series from 16/10/17-16:00 to 17/10/17-06:00 UTC at the Lille site (LOA). (a) The reddest regions indicate a high concentration of particles while the blue regions indicate a very low concentration of particles. (b) Aerosol depolarization which informs us about the shape of the particles and thus their nature, desert or fire particles.
 Graphic credits Q. Hu, LOA

Communications and posters
  • Podvin T., P. Goloub, D. Tanré, I. Veselovskii, V. Bovchaliuk, M. Korensky, A. Mortier, S. Victori, .LILAS, un LIDAR multispectral et Raman pour l’étude des aérosols, de la vapeur d’eau et des nuages, Atelier Experimentation et Instrumentation 2014 (oral presentation)
  • Podvin T, Q. Hu, P. Goloub,  O. Dubovik, I. Veselovskii, V. Bovchaliuk, A. Lopatin, B. Torres, D. Tanré, C. Deroo, T. Lapyonok, F. Ducos, A. Diallo. , LILAS, le Lidar multi spectral Raman polarisé et quelques résultats d’inversions, Atelier Experimentation et Instrumentation 2017 (poster presentation).
  • Hu et al., Aerosol absorption measurements and retrievals in SHADOW2 campaign, ICAC 2017, International Conference on Aerosol Cycle, 21 – 23 Mar, Lille
  • Hu et al., A test of new approaches to retrieve aerosol properties from Photometer-LiDAR joint measurements, ESA/IDEAS Workshop 2017, Lille, 06-07 Apr 2017
  • Hu et al., Retrieval of aerosol properties with Sun/Sky-photometer and LiDAR measurements, ACTRIS-FR, Workshop, Autrans Méaudre en Vercors, 3-5 mai 2017
  • Hu et al., Retrieval of aerosol properties with Sun/Sky-photometer and LiDAR measurements, 28th ILRC, international LiDAR and Radar conference, Bucharest, 25 – 30 June
  • Hu et al., Lidar measurements with 3-depolarization in Lille, 3rd ACTRIS-2 WP2 Workshop, Delft, 13-17 Nov 2017.

Méteo France

METEO-FRANCE network of CIMEL’s instruments

Keywords : Aerosols, LiDARs, monitoring, Earth observation, remote sensing, CAL/VAL, atmosphere, air quality, photometers, aviation, volcanos survey, volcanic ashes, atmospheric monitoring

July 06th 2022

Météo-France is a public administrative institution, the official meteorological and climatological service in France. As such, it exercises the State’s responsibilities in terms of meteorological safety. The institution is also in charge of managing and modernizing an observation network of the atmosphere, the surface ocean and the snow cover in France and overseas.

The institution is also present on an international level as it contributes to the programs and activities of the World Meteorological Organization (WMO) which sets standards that meet the shared needs of its Member States.

Météo-France’s research department, the Centre national de recherches météorologiques (CNRM), is a joint research unit with the CNRS. Météo-France is also a joint supervisor of the Laboratoire de l’Atmosphère et des CYclones (LaCy), the Service des Avions Français Instrumentés pour la Recherche et l’Environnement (SAFIRE), and the Observatoire Midi-Pyrénées (OMP).

Météo-France core missions are linked to the needs related to the protection of people and property: weather forecasting, knowledge of the climate and its evolution, physics and dynamics of the atmosphere and interactions between men, the climate and the atmosphere…

The knowledge of weather conditions is of huge importance for the aviation industry for example. Landing, taking off and even flying safely depends on weather conditions. The perfect example of this huge importance is the eruption of the volcano Eyjafjallajökull which occurred in April 2010. The Icelandic volcano released a thick ash of smoke which disrupted European air traffic, causing five days of complete interruption of traffic: the largest closure of airspace decreed in Europe, not without financial consequences as it led to considerable losses.

Indeed, volcanic ash which tends to settle in the atmosphere is dangerous as it can be sucked into the plane’s engines, then, melt, and finally clog the jet engines. It can cause air plane accidents.

Hence the importance of using state-of-the-art remote sensing measuring instruments to determine for instance the localization, the characterization and the concentration of aerosols in the atmosphere. For this purpose, Météo-France works in collaboration with the LOA (Laboratoire d’Optique Atmosphérique) to manage and maintain a network of efficient solutions and link several instruments such as LiDARs and CIMEL photometers (ready-to-use by AERONET) for more accurate data and considerably reduced uncertainties.

To this end, CIMEL works in close collaboration with Météo-France and ensures to provide quality and constantly improved instruments to meet the urgent needs in terms of security.

Actually, CIMEL also provides instrument synergies between Photometers and LiDARs through a unique monitoring software iAAMS, dedicated to the aerosols study and analysis. The obtained parameters are the characterization of aerosol types, the extinction and backscatter profile of mass concentration. Cimel’s AAMS is able to automatically locate, identify and quantify aerosols, layer by layer, day and night.


US west coast forests are more and more in the grip of Wildfires.

Keywords : Aerosols, LiDARs, MicroLiDARs, Monitoring, Earth observation, Remote sensing, Wildfire, Smoke, Ash, Fires, Climate Change, Global Warming, Atmospheric Monitoring, Mobile Solutions, Air Quality

June 28th 2022

According to a recent UN report, forest fires will continue to increase by the end of the century. It is especially the case on the west coast of the United States, which is one of the countries most affected by this phenomenon. Whether they are natural or human-caused, these fires are devastating on a large scale.

The global warming makes the conditions more favorable to the start of fires and their proliferation. The climate change is worsening the impacts by prolonging the fire seasons.

California is the most wildfire-prone state in the United States. In 2021, over 9000 wildfires burned in the Southwestern state ravishing nearly 2.23 million acres.

Fires are a danger to life on the planet: smoke inhalation, soil degradation and water pollution, destruction of the habitats of many species… Not to mention the aggravation of global warming due to the destruction of forests, crucial to absorb the carbon that we emit.

Therefore, on summer 2019, NASA initiated FIREX-AQ mission so as to investigate on fire and smoke from wildfire using several measurement instruments across the world, and especially in the US.

NASA uses satellites combined with airborne and ground-based instruments to decipher the impact of wildfires.

The emissions of ash clouds resulting from the fire can be transported thousands of miles and can have an impact on air quality for example as they are responsible for a large fraction of the US PM2.5 emissions. Due to its microscopic size, PM2.5 is easily inhaled and has the potential to travel deep into our respiratory tracts, it can also remain airborne for long periods.

To date, wildfire outputs are still poorly represented in emission inventories.

The overarching objectives of FIREX-AQ are to:

  • Provide measurements of trace gas and aerosol emissions for wildfires and prescribed fires in great detail
  • Relate them to fuel and fire conditions at the point of emission
  • Characterize the conditions relating to plume rise
  • Follow plumes downwind to understand chemical transformation and air quality impacts
  • Assess the efficacy of satellite detections for estimating the emissions from sampled fires

For this purpose, CIMEL provided CE376 micro-LiDARs as well as its network of CE318-T photometers through AERONET. These solutions allowed detailed measurements of aerosols emitted from wildfires and agricultural fires to address science topics and evaluate impacts on local and regional air quality, and how satellite data can be used to estimate emissions more accurately.

Figure 1: CE376 micro-LiDAR and CE318-T photometers embarked on a car for FIREX-AQ mobile measurements campaign in Western US (2019).

Indeed, the synergy of the photometer with the mobile CE376 LiDAR allows profiling the extinction at 2 wavelengths (532, 808 nm) and of the Angstrom Exponent (AE). AE vertical profile and the depolarization capabilities of the CE376 allow identifying the aerosol type (fine/coarse). Below are some results from the FIREX-AQ 2019 mission:

Figure 2: Mapping of smoke vertical and spatial dispersion thanks to mobile LIDAR and photometer measurements by Dr. Ioana POPOVICI.   

Figure 3:  Mapping and modelization from FIREX-AQ campaign in Western US (2019) by LiDAR CE376.


FIREX-AQ experience proved that we are able to embark compact remote sensing instruments and install them quickly on site to access harsh environments and get close to fire sources, which has not been done before. Actually, it is the first time a LIDAR reaches that close to fire sources in a mountainous region.



Giles, D. M. and Holben, B. and Eck, T. F. and Slutsker, I. and LaRosa, A. D. and Sorokin, M. G. and Smirnov, A. and Sinyuk, A. and Schafer, J. and Kraft, J. and Scully, A. and Goloub, P. and Podvin, T. and Blarel, L. and Proniewski, L. and Popovici, I. and Dubois, G. and Lapionak, A., (2020), Ground-based Remote Sensing of the Williams Flats Fire Using Mobile AERONET DRAGON Measurements and Retrievals during FIREX-AQ, 2020, AGU Fall Meeting Abstracts.


Volcano eruption of Mount Aso in Japan – A peak of AOD due to volcanic ashes

Keywords : Photometer, Aerosols Optical Depth, Atmosphere, volcanic eruption, Ashes.

17th November 2021

The volcano of Mount Aso located in the south of the Japanese archipelago on the island of Kyushu erupted this Wednesday, October 20, releasing volcanic ashes up to 3,5 kilometers in the atmosphere during the strongest eruption time.

The volcano had not been active since 2016, local authorities are advising residents to remain vigilant of volcanic ashes and gases on the leeward side of the Nakadake crater. As a matter of fact, the gas and projectiles created a cloud that is denser than the surrounding air and which is an extremely hot ash plume due to the turbulence between the flow and the overlying air.

One of the Cimel CE318-T photometer is currently providing atmospheric aerosols measurements near the volcano eruption. Indeed, the NASA AERONET site based on the offshore platform of Ariake observation tower located in Ariake Sea in Japan, is about 5 kilometers from the coast of Saga city in Ariake Sea.

Figure 1: Google Earth satellite image showing the position of the NASA AERONET Ariake Tower site in relation to the Mount Aso volcano in Kyushu Island (Japan).

Figure 2: Data provided by the Cimel photometer in the Ariake Tower operated by Saga University, depicting Aerosols Optical Depth in the atmosphere.

We have collected data recorded by the Cimel CE318 photometer which measures the Aerosols Optical Depth (AOD) in the atmosphere. We note a peak of the AOD on October 21, a day after the volcanic eruption.

With the addition of Cimel CE376 LiDAR, it would be possible to obtain more high added value parameters such as the characterization, location and the extinction and backscatter profile of mass concentration of this kind of ash aerosols in the atmosphere.

See more on our AAMS solution which consists in the synergy between our LiDARs and our photometers.


La Palma eruption (Canary Islands) – volcanic plumes tracking by our LiDARs

Keywords : LiDARs, Aerosols, Atmosphere, La Palma, Cumbre Vieja volcano, CE376.

6th October 2021

The Cumbre Vieja volcano on La Palma in the Canary Islands erupted on 19th September for the first time since 1971 resulting in large lava flows and evacuations.

Due to the volcanic eruption, nearly 10 000 tons of sulfur dioxide are released in the atmosphere every day. The risks generated are acid rain and deterioration of air quality which can lead to respiratory problems.

In a few words, this phenomenon is due to the fact that the lava of the volcano which reaches 1000°C meets the sea water which is at around 20°C. Therefore, the sodium chloride contained in the sea breaks down the water into oxygen and hydrogen. However, when hydrogen meets chlorine, they turn into hydrochloric acid which is an extremely dangerous gas.

There are many consequences such as the impact on the air quality which directly concerns the surrounding populations who breathe a toxic smoke harmful for their health.

Air traffic is also strongly impacted as all the flights departing from the island have been cancelled. These disturbances are also due to the lack of instruments measuring aerosols (such as LiDARs) to accurately identify the location of the volcanic ash as well as its characteristics and concentration.

Our CE376 LiDARs in AEMET (Izaña) is tracking plumes of the volcanic ash from the volcanic eruption on La Palma and here are some results to illustrate it.

Figure 1: Quicklook revealing the volcano plumes as captured on 24 September by AEMET in Izaña.

The volcano is propelling air into the atmosphere which meets a thermal inversion – a reversal of the normal behavior of temperature in the troposphere where a layer of hot air sits above a layer of cooler air.

Figure 2: Picture by Virgilio Carreño (Izaña Atmospheric research center, AEMET) showing the interaction of the gas and ash plume of the eruptive column leaving the volcano with the altitude thermal inversion layer of the atmosphere through which the Sahara desert dust transcends.

ESA – New remote sensing tech on satellite for atmospheric measurements

VEGA Rocket

ESA – New remote sensing tech on satellite for atmospheric measurements


On September 3rd 2020, ESA has launched 42 small satellites aboard a Vega rocket from Kourou in French Guiana for the Copernicus Project.

This new type of satellites capable of measuring CO2 emissions to the nearest kilometer and pinpointing their origin.

One of these nanosatellites, PICASSO, carries remote sensing technology developed which will be used to undertake measurements in the upper layers of Earth’s atmosphere.

PICASSO stands for Pico-Satellite for Atmospheric and Space Science Observations and it’s the first CubeSat nanosatellite mission of the Royal Belgian Institute for Space Aeronomy.

Weighing only 3.5kg, it carries two measuring instruments for atmospheric research: A Visible Spectral Imager for Occultation and Nightglow (VISION) and a system to conduct plasma measurements in the ionosphere, the Sweeping Langmuir Probe (SLP).

This project of analysis and collection of satellite data will be carried out over 5 years. The aim is to obtain as much precise information as possible on the quantification of gases in the air.

We will be able to know exactly the real CO2 emission by country, cities and the origin of gases (if it’s anthropogenic or natural).

Thanks to this initiative, more and more surveillance systems will be sent into space over the next few years, which will help develop the market for remote sensing solutions.

Cimel will be part of this development by bringing additional data thanks to its photometers and LiDARs to help calibrate and validate data from satellites.

Credits: ESA-M. Pedoussaut

Earth Observation Satellites & Ground Monitoring  Solutions – an essential synergy for Air Quality and Climate Change

Earth Observation Satellites & Ground Monitoring  Solutions – an essential synergy for Air Quality and Climate Change

April 30, 2020

Atmospheric monitoring and climate analysis are strategic missions in order to improve the understanding of air quality dynamics and climate change evolutions. This in turn is a pre-requisite for providing reliable information reports with real data measurements and to help decision makers and end-users to understand the impacts and causes of air pollution with atmospheric impacts and to act upon it.

Satellite data is key for atmospheric and climate monitoring by providing a continuous and global view of the Earth parameters. These data are essential inputs for forecast models by improving their accuracy.

By combining satellite observations with models of the atmosphere and measurements from ground-based instruments, like Cimel Remote Sensing Solutions, it is possible to measure accurately and forecast aerosols (particles suspended in the air), as well as quantify gases level (ozonenitrogen dioxidesulphur dioxidecarbon monoxide…) and several other kind of environmental parameters (planetary boundary layer, water leaving reflectance for Ocean color, solar radiation, water vapor, atmospheric concentration profiles PM2.5/PM10…).

Cimel solutions keep working continuously and automatically, to help the calibration of satellite instruments and validate their data. Furthermore, Cimel is always active to support the various research activities from the worldwide scientific community.

In this video, different aerosols are highlighted by color, including dust (orange), sea salt (blue), nitrates (pink) and carbonaceous (red), with brighter regions corresponding to higher aerosol amounts.

See more on:

Credit: NASA Goddard Space Flight Center