Pearl and Opal CE318-T photometers recording AOD and measurements in Canada’s high Arctic for AEROCAN.

Keywords : Aerosols, photometer, monitoring, Earth observation, remote sensing, CAL/VAL, Arctic.

March 23rd 2022

The Canadian Arctic is probably one of the best areas to conduct climatological studies, especially on global warming given the purity of the atmosphere in this zone, especially due to the absence of anthropological pollution.

Nevertheless, this rather hostile land, due to its temperatures, can make the difficulties of recording measurements very real. Consequently, there is a lack of measurements in the Arctic, hence the need to install platforms with robust and reliable measuring instruments.

Some of those platforms, especially PEARL and OPAL, have a particular emphasis on the Arctic because Canada has a significant portion of its territory in the Arctic.

The Polar Environmental Atmospheric Research Lab (PEARL) and the zerO altitude Polar Atmosphere Laboratory (OPAL) which is part of PEARL, is operated by the CAnadian Network for the Detection of Atmospheric Change (CANDAC) which is a member of AEROCAN. Formed in 2005, PEARL constitutes a network of universities and government researchers dedicated to studying the changing atmosphere over Canada.

The first task of PEARL was to renew and operate the existing laboratory at Eureka in Nunavut, which was created to contribute to the world-wide effort to intensively study the Arctic region through AEROCAN.

The AEROCAN photometer network is run as a joint collaboration between the Université de Sherbrooke and the Meteorological Service of Canada (MSC). It is a full-fledged sub-network of the much larger AERONET network of Cimel photometers and benefits from all the services that AERONET offers.


  • Understanding atmospheric change over Canada
  • Integration of measurements taken from space, aircraft, balloons and the ground
  • Provision of quality-controlled research datasets to researchers
  • Linkage with international networks for data exchange and supranational planning

In addition, PEARL undertakes measurements that are simultaneous with those made by various satellite instruments. These “validation” measurements are extremely effective because of the location of PEARL and OPAL, and they further enhance the science return of the research as they use state-of-the-art technology solutions like the CE318-T Photometer.

PEARL is located at Eureka, Nunavut (80N, 86W) on Ellesmere Island in Canada’s high Arctic, 450 km north of Grise Fiord, the most northerly permanent settlement. This photometer site is 1,100 km from the North Pole. OPAL is located about 12 km southeast of the PEARL ridge lab which is at an elevation of 610 m. This dual placement was designed to study the layer between the two sites as well as provide an element of redundancy for the AOD measurements.

Figure 1: Location of PEARL and OPAL photometer sites (upper pictures : 2007 CANDAC/Ovidiu Pancrati, bottom picture: Norm O-Neill, Université de Sherbrooke)
Figure 2: PEARL CE378 Photometer pointing to the sun for a measurement scenario
Figure 3: Latest measurements from Opal (above) and Pearl (bottom) photometers depicting AOD (Aerosol Optical Depth). Credits: NASA AERONET:


A multi-year AOD and effective radius climatology for the high Arctic showed a number of consistent features using the Cimel CE318-T Photometer:
• Spring to summer decrease of fine-mode AOD (probably attributable to biomass burning and/or anthropogenic pollution)
• Significant correlation of fine mode AOD with CO (Carbon monoxide) concentration which indicates a predominance of biomass burning aerosols throughout the entire year
• West to East decrease in AOD on a pan-Arctic scale
Another study (Antuña-Marrero et al., 2022) has been conducted for water vapor research.
It shows that it is feasible to use Cimel CE318-T Photometer AERONET observations in the Arctic for water vapor research, considering the robust quantification of its dry bias that has been established.
As a matter of fact, AERONET imposes standardization of instruments, calibration, processing and distribution that Cimel is the exclusive provider. Its IWV (Integrated Water Vapor) observations are an ideal standard dataset to re-calibrate or homogenize the rest of the instrumental IWV observations to a predefined absolute standard dataset.


  • Antuña-Marrero, Juan Carlos & Román, Roberto & Cachorro, Victoria & Mateos, David & Toledano, Carlos & Calle, Abel & Antuña Sánchez, Juan Carlos & Vaquero-Martínez, Javier & Antón, Manuel & Baraja, Ángel. (2022). Integrated water vapor over the Arctic: Comparison between radiosondes and sun photometer observations. Atmospheric Research. 270. 106059. 10.1016/j.atmosres.2022.106059.
  • AboEl‐Fetouh, Y., O’Neill, N. T., Ranjbar, K., Hesaraki, S., Abboud, I., & Sobolewski, P. S. (2020). Climatological‐scale analysis of intensive and semi‐intensive aerosol parameters derived from AERONET retrievals over the Arctic. Journal of Geophysical Research: Atmospheres, 125, e2019JD031569.
  • Mölders, N. and Friberg, M. (2020) Using MAN and Coastal AERONET Measurements to Assess the Suitability of MODIS C6.1 Aerosol Optical Depth for Monitoring Changes from Increased Arctic Shipping. Open Journal of Air Pollution, 9, 77-104.


Eureka offshore oil platform provides continuous aerosols data recorded by CE318-TV12-OC (SeaPRISM) for NASA AERONET.

Keywords : Aerosols, photometer, water radiance, monitoring, ocean properties, ocean color, Earth observation, remote sensing, CAL/VAL, SeaPRISM.

February 9th 2022

Since 2002, more than 31 OC measurement sites have been integrated on the NASA AERONET OCEAN COLOR network through offshore fixed platforms and coastal platforms all around the world. Thanks to numerous collaborations between environmental sciences and energy industries such as discussed below, the number of Ocean Color measurement sites keeps growing.

In collaboration with University of Southern California (USC), the SeaPRISM site at the oil rig platform Eureka was installed in the Los Angeles Harbor and was initially operational in April 2011. CE318-TV12-OC (SeaPRISM) photometers  are part of the AERONET network of automated instruments designed to make automated measurements of aerosols around the world.

The SeaPRISM instrument has been modified to also view the ocean surface and measure ocean color remote sensing reflectance as well as the aerosol measurements. Data is currently flowing to NASA AERONET as well as NRL-SSC (The Naval Research Laboratory detachment at  Stennis Space Center (SSC), Mississippi) and Oregon State University (OSU) for matchups. Data has been collected routinely since June 2012 to date.

Continuity of the ocean color products between ocean color satellites is required for climate studies, as well as to enhance the operational products used in ecological monitoring and forecasting, such as accurately monitoring ocean water quality and determining changes along our coastlines. In addition, inter-satellite product comparisons are essential for data continuity into the future.

The JPSS (Joint Polar Satellite System) calibration and validation team has developed an infrastructure to evaluate VIIRS (Visible Infrared Imaging Radiometer Suite) Ocean Environmental Data Records (EDRs): routinely nLw(λ) and chlorophyll are evaluated against existing satellites data measurements. Ocean color products are based on nLw( λ) from which specific products of chlorophyll, backscattering coefficients, absorption coefficients, and diffuse attenuation coefficients  are computed.

Therefore the accurate radiometric retrieval of the nLw( λ) is considered essential for the production of any ocean color product. A web-based with the VIIRS data matching the satellite data from Platform Eureka SeaPRISM was created in order to provide reliable data. The CE-318 of the oil platform Eureka helps to validate the satellite data provided by VIIRS on the JPSS.

Here are some results performed recently by the CE318-TV12-OC (SeaPRISM) located at Platform Eureka depicting the Normalized Water-Leaving Radiance.

Figure 1: Measurements performed at AERONET-OC Eureka oil platform, California – Normalized Water-Leaving Radiance [Lw]N.
Figure 2: CE318-TV12-OC (SeaPRISM) on site Eureka oil platform, California (USA).


Curtiss O. Davis, Nicholas Tufillaro, Jasmine Nahorniak, Burton Jones, and Robert Arnone “Evaluating VIIRS ocean color products for west coast and Hawaiian waters”, Proc. SPIE 8724, Ocean Sensing and Monitoring V, 87240J (3 June 2013);


The implantation of CE318-T photometers on offshore and coastal platforms constitutes a major turning point for atmospheric and ocean color applications.

Keywords : Aerosols, photometer, water radiance, monitoring, ocean properties, ocean color, Earth observation, remote sensing, CAL/VAL, SeaPRISM.

17th December 2021

The main substances that affect the color of the ocean include dissolved organic matter, living phytoplankton with chlorophyll pigments, and non-living particles like marine snow and mineral sediments. Ocean color data have a critical role in operational observation systems monitoring coastal eutrophication, harmful algal blooms, and sediment plumes. Scientists rely on satellite observations to monitor Ocean Color (OC) parameters, such as chlorophyll a concentration (Chla) and inherent optical properties of water (IOP), to better understand the role of the ocean in the Earth’s climate.

However, the current satellite measurement systems can provide only coarse spatial resolution, with relevant lack of data.

Thus, AERONET Ocean Color saw the light of day in 2002. This new component of AERONET (NASA AErosol RObotic NETwork) aims at providing more data concerning satellites measurements as there is a lack of insights in the monitoring of marine aerosols and water radiance. Since 2002, more than 31 OC measurement sites have been integrated on the network through offshore fixed platforms and coastal platforms all around the world.

Its particularity is that the measurements are taken from the radiance emerging from the sea using CE318-TV12-OC (SeaPRISM) Cimel photometers. By measuring the water radiance from the sea with instruments installed on coastal/offshore platforms or boats, Cimel improves the accuracy of satellites measurements. AERONET decided in 2015, after full validation, to accept only the CE318-T for new photometers entering the network. Below is a representative drawing of the measurement principle of the CE318-TV12-OC (SeaPRISM) photometer:

Figure 1: Measurement principle of the Cimel CE318-TV12-OC (SeaPRISM).

Many missions are conducted by AERONET-OC to collect ocean color data and measurements. Below, one of these campaigns conducted on an offshore platform (AAOT) in the Adriatic Sea.

Figure 2: AERONET OC site located in the Acqua Alta Oceanographic Tower (AAOT) in the Gulf of Venice in the Northern Adriatic Sea in July 2018.

Figure 3: Measurements performed at AERONET-OC AAOT – Scatterplot of LIOP WN(λ) versus LChla WN(λ).

Click Here to read the article!

Citation: Zibordi, Giuseppe, Brent N. Holben, Marco Talone, Davide D’Alimonte, Ilya Slutsker, David M. Giles, and Mikhail G. Sorokin. «Advances in the Ocean Color Component of the Aerosol Robotic Network (AERONET-OC)”, Journal of Atmospheric and Oceanic Technology 38, 4 (2021): 725-746, accessed Sep 17, 2021,


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.

ATTO project

ATTO: the Amazon Tall Tower Observatory, an Amazon research project

Keywords : ATTO, Aerosols, Photometer, Atmosphere

The Amazon Tall Tower Observatory (ATTO) is the world’s highest research facility located in the middle of the Amazon rainforest in northern Brazil. It is a research site with a 325 meters tower for atmospheric observations.

This joint German-Brazilian project was launched in 2008 in order to further the understanding of the Amazon rainforest and its interaction with the soil beneath and the atmosphere above. This is made possible by recording continuously meteorological, chemical and biological data such as greenhouse gases or aerosols.

Scientists and researchers on site hope to gain insights into how the Amazon interacts with the atmosphere and the soil. This region is very important for the global climate as Saharan dust, biomass smoke from Africa, urban and marine aerosols come from long distances due to the winds. It is vital to get a better understanding of this area for environmental decisions.

On this gigantic tower, a CE318-T photometer is installed at 210 meters from the ground and allows a more efficient calculation of the quantity of aerosols present in the air around this site. The photometer uses NASA’s AERONET calibration system to collect the most reliable data possible.

Cimel photometer on the tower (© NASA AERONET)

At the core of the project is to learn more about biogeochemical cycles, the water cycle and energy fluxes in the Amazon. The goal is to determine their impact on global climate and how they are influenced by the changing climate and land-use change.

ATTO teams strive to close a gap in the global climate monitoring network and want to improve climate prediction models and to recognize the importance of the Amazon within the climate system.

Thanks to our sun-photometer, the scientists on site were able to collect information on daily mean AOD values at 550 nm wavelength.  These data allowed us to analyze the soils present in the atmosphere of the Amazon forest. Here some results of the ATTO project with our sun-photometer between August and September 2019.

Citation: Hassan Bencherif, Nelson Bègue, Damaris Kirsch Pinheiro, David Du Preez, Jean-Maurice Cadet, et al.. Investigating the Long-Range Transport of Aerosol Plumes Following the Amazon Fires (August 2019): A Multi-Instrumental Approach from Ground-Based and Satellite Observations. Remote Sensing, MDPI, 2020, Advances in Remote Sensing of Biomass Burning, 12 (22), pp.3846.

Read the article here!

If you want to discover or learn more about this major project, visit:

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

GPS roll-over

GPS roll-over the 3rd of November 2019 on the CE318-T

Important for existing CE318-T customers:

The GPS week counter has been reset the 3rd of November 2019.

Location data reports remained correct while the date and week number are affected. 

The CIMEL CE318-T photometer is impacted by the GPS week counter reset.

It is necessary to use the last version of the firmware for the photometer to remain operational.

Please see the related process bellow to check and update the right firmware version at your earliest convenience to fix the desynchronization.

You will need a computer and to be on site to connect on the control unit and update the firmware.

If you have any question or concern regarding the GPS roll-over issue, feel free to contact us.

Download the procedure here.

N.B.: If you are registered in AERONET, please contact the NASA AERONET team.

Sunbelt Spectra comparison with Standard ASTM G173: the Chilean case

Sunbelt Spectra comparison with Standard ASTM G173: the Chilean case

December, 2017

Two spectra of solar direct normal irradiance (including circumsolar) are estimated based on spatio-temporal averages of the relevant atmospheric parameters extracted from two different databases: MODIS satellite sensor retrievals and AERONET sun photometer network. The satellite database is used to calculate an average spectrum for the area of the Atacama Desert. The AERONET database is used for two purposes: (i) to apply bias-removal linear methods to correct the MODIS parameters over Atacama, and (ii) to calculate an average local spectrum for the Paranal station. The SMARTS radiative transfer model is used to obtain the three spectra developed in this study. Both the Atacama and Paranal spectra are compared against each other and also to the world reference, ASTM G173. In one of the cases, significant differences are found for short wavelengths. In order to quantify the relative importance of these spectral differences, the propagation of errors due to the use of each spectrum is evaluated for CSP applications over the Atacama Desert, considering twelve different scenarios involving the reflectance, transmittance or absorptance of various materials.

Citation: Marzo, Aitor & Polo, Jesus & Wilbert, Stefan & Gueymard, Chris & Jessen, Wilko & Ferrada, Pablo & Alonso-Montesinos, Joaquín & Ballestrín, Jesús. (2017). Sunbelt Spectra comparison with Standard ASTM G173: the Chilean case. AIP Conference Proceedings. 2033. 10.1063/1.5067195.


Image source: Pixabay

COBIACC campaign

COBIACC campaign

Is the rural atmosphere better than elsewhere?

For the entire month of July in Caillouël-Crépigny (France), scientists from the University of Lille and ATMO Hauts-de-France will analyze particles in the air and their impact on health in rural areas.

Since 28 June, more than twenty air pollution measuring devices deployed over 100 m² in the commune of Caillouël-Crépigny (02) may answer this question.

Objectives: To understand the formation and the composition of particles and their precursors in the air in a rural environment during the summer period.

The sensors collect dust from the countryside and nearby dust from forests, roads, buildings and industries in the distance.

The facility consists of four containers installed on 100 m² in the village square of Caillouël-Crépigny. They accommodate twenty-two observation instruments including our Cimel Sun Sky Lunar CE318-T photometer as well as our CE376 micro-LiDAR. These instruments, unique in France, measure the impact of climate change on air quality, biodiversity and health. Thirty researchers take turns night and day to study the chemical modifications of particles during periods of high heat.

This campaign was named COBIACC for Campagne d’OBservation Intensive des Aérosols et précurseurs à Caillouël-Crépigny. It is the result of a partnership between Labex CaPPA, a laboratory of excellence in Lille, CPER Climibio, an environmental project involving 16 laboratories in the Hauts-de-France and Atmo Hauts-de-France, the regional air quality observatory.

Laboratories involved: