Posted on

US-WILDFIRES

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.

Bibliography:

https://www.agora-lab.fr/_files/ugd/376d34_4116704968934963a6aea9b5719f2824.pdf

https://ui.adsabs.harvard.edu/abs/2020AGUFMA191…09G/abstract

https://ui.adsabs.harvard.edu/abs/2019AGUFM.A23R3049H/abstract

https://ui.adsabs.harvard.edu/abs/2020AGUFMA191…09G

Citation:

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.

Posted on

AEROCAN ARCTIC PHOTOMETERS

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.

Objectives:

  • 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 CE318 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: https://aeronet.gsfc.nasa.gov/

Results:


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.

References:

  • 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. https://doi.org/10.1029/2019JD031569
  • 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.
    https://doi.org/10.4236/ojap.2020.94006
Posted on

PLATFORM EUREKA

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).

Bibliography:

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); https://doi.org/10.1117/12.2016177

http://businessdocbox.com/Business_Software/112273525-Establishing-a-seaprism-site-on-the-west-coast-of-the-united-states.html

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/8724/1/Evaluating-VIIRS-ocean-color-products-for-west-coast-and-Hawaiian/10.1117/12.2016177.short?SSO=1

https://earthdata.nasa.gov/earth-observation-data/near-real-time/download-nrt-data/viirs-nrt

Posted on

AERONET-OC

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, https://doi.org/10.1175/JTECH-D-20-0085.1

Posted on

VOLCANO MOUNT ASO

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.

Posted on

VOLCANO LA PALMA

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.

Posted on

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: https://www.attoproject.org/

Posted on

GAWPFR WMO reference

New AOD tracking technique by ESA with AERONET and the GAWPFR WMO reference

Keywords : Aerosols, Atmosphere, Sun/Sky/Lunar photometer, Meteorology

The World Meteorological Organization (WMO) has recognised the Word Optical Depth Research and Calibration Center (WORCC) as the primary reference center for Aerosol Optical Depth measurements. The WORCC is a section within the World Radiation Center at the Physikalisch-Meteorologisches Observatorium Davos (PMOD/WRC), located in Davos, Switzerland.

With its new QA4EO project, European Space Agency (ESA) wishes to obtain homogeneous results between the various passive monitoring networks of passive remote sensing of aerosol optical properties, presents in Davos and in France at the Observatoire de Haute Provence (OHP).

Consequently, a precision filter radiometer (PFR) travelling standard was installed at the European calibration site of AERONET to supply continuous traceability of aerosol optical depth measurements to the World reference maintained at Davos through a PFR Triad.

The precision filter radiometer was installed in July 2020 at the Observatoire de Haute Provence (OHP) on a solar tracker provided by the Laboratoire d’Observation Atmosphérique (LOA) next to our 4 sun photometers (CE318-T).

OHP’s platform, with four CIMEL Sun/Sky/Lunar photometers CE318-T and the PFR traveling (at the right of the picture).

The measurements of spectral solar irradiance during clear sky periods are used to retrieve AOD from our photometers with AERONET calibration and the PFR.

You can follow the comparison between these two instruments in real time on this web page. This real-time analysis allows for continuous monitoring and quality control of the measurements provided by these two devices.

Real-time monitoring of the measurement analysis of the two instruments on 24 March 2021 – Source: https://www.pmodwrc.ch/en/world-radiation-center-2/worcc/gaw-pfr/ohp/

After 6 months of comparison (August 2020 to January 2021) between the two networks, results have been very promising with an Aerosol Optical Depth difference of less than 0.01, corresponding perfectly to the WMO criteria for AOD traceability for 3 of its 4 channels. This shows that the results provided by CIMEL CE318-T photometers are in line with the WMO expectations and that CIMEL photometers may be used as an instrument of reference for other research projects.

Other projects are in parallel with this one such as the 19ENV04 project funded by EURAMET and the European Commission to extend the traceability of international unit systems through the characterization and calibration of our Sun/Sky/Lunar photometers from these networks (See more information here).

This collaboration between research institutes and the European metrology community will establish a consistent framework providing calibrations of our Sun/Sky/Lunar photometers with traceability to the SI as well as comprehensive uncertainty budgets that will be a necessary part of the data provided to the users and actors of these networks.

References:
Kazadzis, S., Kouremeti, N., Nyeki, S., Gröbner, J., and Wehrli, C.: The World Optical Depth Research and Calibration Center (WORCC) quality assurance and quality control of GAW-PFR AOD measurements, Geosci. Instrum. Method. Data Syst., 7, 39-53, https://doi.org/10.5194/gi-7-39-2018, 2018.

Posted on

MAP-IO campaign

Ship-borne CE318-T photometer aboard the Marion Dufresne in the frame of the MAP-IO.

January 11th – March 8th2021

Since the beginning of January 2021, one of our CE318-T photometers is permanently embarked on the Marion Dufresne as part of the MAP-IO (Marion Dufresne Atmospheric Program – Indian Ocean) research programme.

The objective of a permanent installation of our photometer on the Marion Dufresne is to allow the measurement of atmospheric aerosols from mobile platforms, and to extend and automate the coverage of the AERONET network.

CE318-T CIMEL photometer aboard the Marion Dufresne (Credits : LACY/University of la Réunion)

In future campaigns, our photometer will be used mainly in the Southern Hemisphere and the Indian Ocean to measure the aerosol optical depth (AOD). The new campaign that has just started is the result of preparatory campaigns like OCEANET and SEA2CLOUD, during which the system has been tested, improved and validated.

Below, the preliminary results of the campaign obtained thanks to satellite data transmitted to the LOA/CNRS to measure spectral AOD, water vapour content, Ångström exponent, and sky radiance for AERONET.

Map of the first daytime recorded AOD (level 1.5) between 13 and 31 January 2021 (Source: Luc Blarel at LOA/CNRS/U. Lille).

Objectives

  • To monitor long-term atmospheric changes in the Indian and Austral oceans regions which are very poorly documented (IR ACTRIS and ICOS).
  • To calibrate and validation data from satellites.
  • To understand better the ocean-atmosphere exchanges and regional pollution by improving and adapting and adapting the parametizations used in numerical weather and climate predition models over the Indian and the Austral oceans.

If you want to know more about this campaign click here !

Key words: Aerosols, Atmosphere, sun/sky/lunar photometer, Meteorology

  • Logo Cimel
Posted on

ROSAS – CESBIO

CESBIO_ROSAS

ROSAS – A new BRDF photometer installed in Lamasquère by CESBIO

The Lamasquère site (France) is now equipped with a CIMEL 12 filters photometer (CE318-TU12) which measures direct and diffuse irradiation, and the directional reflectance of the surface (BRDF).

This system, installed in March 2021, is called RObotic Station for Atmosphere and Surface (ROSAS) and operates mounted on top of a 10 m high mast in a field on the agricultural area of Lamothe farm in Lamasquère (France). The CESBIO ROSAS station is thus the 3rd site of this type worldwide after the CNES station in La Crau (France) and the CNES/ESA station in Gobabeb (Namibia), and the first to characterize an agricultural vegetated surface, with seasonal and inter-annual variations of the cover.

The spatial and temporal heterogeneity of the surface of this new site makes it more suitable for the validation of surface reflectance (after atmospheric correction), than for the absolute calibration of satellite sensors, as it is the case for La Crau and Gobabeb. When the Lamasquère field crops become very green and dense, the surfaces are dark and the atmospheric correction errors have a strong impact on the reflectance estimates, and when the crops are mature or the plot is bare ground, the adjacency effects due to the nearby forest become strong. Such in situ measurements are thus of primary interest to CESBIO, CNES and the broader scientific community.

The data are automatically transmitted to CESBIO and CNES every hour via the mobile phone network (GPRS), and processed periodically to derive the filtered bi-directional reflectance distribution function (BRDF).

Here below, you can find the first BRDF measurements acquired a few days after the validation of the station:

Polar diagrams of surface reflectances measured by the ROSAS station in Lamasquère. The 0° azimut corresponds to observations towards the South. The top left image was taken in the morning, the top right around noon, bottom left in the afternoon, and bottom right later on after the arrival of clouds. The yellow dots indicate the position of the sun . The radius of the graph corresponds to the zenith angle, and the other dimension is the azimuth with regard to the North.

Keywords: CIMEL, photometer, ROSAS, CNES, AERONET, CESBIO, BRDF

More information on : https://lnkd.in/dhh7KXN