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Aerosol optical depth comparison between GAW-PFR and AERONET-Cimel radiometers from long-term (2005–2015) 1 min synchronous measurements

CE318-T Izaña

Aerosol optical depth comparison between GAW-PFR and AERONET-Cimel radiometers from long-term (2005–2015) 1 min synchronous measurements

August 9, 2019

A comprehensive comparison of more than 70 000 synchronous 1 min aerosol optical depth (AOD) data from three Global Atmosphere Watch precision-filter radiometers (GAW-PFR), traceable to the World AOD reference, and 15 Aerosol Robotic Network Cimel radiometers (AERONET-Cimel), calibrated individually with the Langley plot technique, was performed for four common or “near” wavelengths, 380, 440, 500 and 870 nm, in the period 2005–2015.

The goal of this study is to assess whether, despite the marked technical differences between both networks (AERONET, GAW-PFR) and the number of instruments used, their long-term AOD data are comparable and consistent.

The percentage of data meeting the World Meteorological Organization (WMO) traceability requirements (95 % of the AOD differences of an instrument compared to the WMO standards lie within specific limits) is >92 % at 380 nm, >95 % at 440 nm and 500 nm, and 98 % at 870 nm, with the results being quite similar for both AERONET version 2 (V2) and version 3 (V3). For the data outside these limits, the contribution of calibration and differences in the calculation of the optical depth contribution due to Rayleigh scattering and O3 and NO2 absorption have a negligible impact. For AOD >0.1, a small but non-negligible percentage (∼1.9 %) of the AOD data outside the WMO limits at 380 nm can be partly assigned to the impact of dust aerosol forward scattering on the AOD calculation due to the different field of view of the instruments. Due to this effect the GAW-PFR provides AOD values, which are ∼3 % lower at 380 nm and ∼2 % lower at 500 nm compared with AERONET-Cimel. The comparison of the Ångström exponent (AE) shows that under non-pristine conditions (AOD >0.03 and AE <1) the AE differences remain <0.1. This long-term comparison shows an excellent traceability of AERONET-Cimel AOD with the World AOD reference at 440, 500 and 870 nm channels and a fairly good agreement at 380 nm, although AOD should be improved in the UV range.

Citation: Cuevas, E., Romero-Campos, P. M., Kouremeti, N., Kazadzis, S., Räisänen, P., García, R. D., Barreto, A., Guirado-Fuentes, C., Ramos, R., Toledano, C., Almansa, F., and Gröbner, J.: Aerosol optical depth comparison between GAW-PFR and AERONET-Cimel radiometers from long-term (2005–2015) 1 min synchronous measurements, Atmos. Meas. Tech., 12, 4309–4337, https://doi.org/10.5194/amt-12-4309-2019, 2019.

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IAOOS

IAOOS – Ice Atmosphere Arctic Ocean Observing System

FEBRUARY 2011 – DECEMBER 2019

The IAOOS Project’s objective is to develop and maintain an automated observation network of ice-tethered platforms across the Arctic Ocean which will simultaneously and independently transmit via satellite, in near real time, the state of the ocean, sea ice and the lower atmosphere.

The project uses a CIMEL microlidar to monitor the atmosphere (T, conso, f optical window).

IAOOS project

The IAOOS equipment is based on 15 autonomous platforms working at any time in the Arctic Ocean, for a period of 7 years. Every platform, made up of 3 elements ocean / atmosphere / sea ice, drifts with the sea ice, the surface winds and the oceanic currents. They are designed to stay at the sea-ice surface and float on the surface of the ocean, with an autonomy of 2 years.

The IAOOS project plans the deployment of 6 platforms per year, following the plan of deployment of the first 15 platforms. Two periods of deployments are planned every year: in spring and in autumn.

Project
Observing, understanding and quantifying climate changes in the Arctic. IAOOS is specifically concerned with the potential for a significantly reduced sea ice cover, and the impacts this might have on the environment and on human activities, both regionally and globally.

Objectives

  • Deploy and maintain an integrated observing system providing simultaneous observations of the ocean, ice and lower atmosphere in real time in the Arctic
  • Complementary to satellite observations
  • Better understanding of interactions
  • Feed operational models
  • Improve predicting capabilities

Equipment on the IAOOS Platforms

  • CTD vertical profilers from 0 to 1000 m depth (conductivity, temperature, depth)
  • Ice Mass Balance (IMB)
  • Temperature and pressure sensors
  • CIMEL microlidars: T, conso, f optical window for atmosphere monitoring
  • Optical depth sensors (ODS)

Partners

IAOOS platform

References

  • Vincent Mariage, Jacques Pelon, Frédéric Blouzon, Stéphane Victori. IAOOS microlidar development and firsts results obtained during 2014 and 2015 arctic drifts . EPJ Web of Conferences, EDP Sciences, 2016, The 27th International Laser Radar Conference (IRLC 27), 119, 02005 (4 p.)(https://hal-insu.archives-ouvertes.fr/insu-01175931)
  • Vincent Mariage, Jacques Pelon, Frédéric Blouzon, Stéphane Victori, Nicolas Geyskens, Nadir Amarouche, Christine Drezen, Antoine Guillot, Michel Calzas, Magali Garracio, Nicolas Wegmuller, Nathalie Sennéchael, and Christine Provost, “IAOOS microlidar-on-buoy development and first atmospheric observations obtained during 2014 and 2015 arctic drifts,” Opt. Express 25, A73-A84 (2017) (https://doi.org/10.1364/OE.25.000A73)
  • Vincent Mariage. Développement et mise en oeuvre de LiDAR embarqués sur bouées dérivantes pour l’étude des propriétés des aérosols et des nuages en Arctique et des forçages radiatifs induits. Physique Atmosphérique et Océanique [physics.ao-ph]. Université Pierre et Marie Curie – Paris VI, 2015. Français. ⟨NNT : 2015PA066580⟩
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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:

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Mobile Automatic Aerosol Monitoring Solution project (M-AAMS)

Mobile Automatic Aerosol Monitoring Solution project (M-AAMS)

Mobile Automatic Aerosol Monitoring Solution project (M-AAMS)

The team of scientists left Lille on Monday morning, direction the « Observatoire de Haute Provence » located in Aix-en-Provence.

Along its trip, the car takes continuous measurements of the atmosphere.

Scientists on board follow them and make sure that all the instruments work properly. The car is not only equipped with a wide range of instruments, but also with a camera and an internet connexion: all needed to document the trip of the car in real time!

Follow the adventure of the #CaPPA_Mobile on twitter.

If the system has already been used locally, this time the route extends from Lille to Aix-en-Provence, nearly 1000 km. This experience is part of Ioana Popovici’s thesis work: “Measurement of aerosol variability at high spatial and temporal resolution, in connection with air quality, using an innovative mobile system. »

This time, the vehicle is equipped with a Cimel CE370 LiDAR (532 nm), the mobile PLASMA photometer (340-1600 nm), a granulometer (GRIMM) and a weather station.

The data collected by the mobile system is being analysed and validated. An inter-comparison of the data will be made with the data collected by the fixed measurement stations of the Haute Provence Observatory and the ATMO stations located along the route. Access to online data of the instrumented car.

The science team relied on good weather to collect as much data as possible. Although the sky cleared several times, clear, cloudless sky conditions were not frequently encountered. Under these circumstances it is difficult to carry out solar photometry measurements and to obtain additional information by combining LIDAR with a solar photometer. However, LIDAR has observed the vertical and spatial variability of the atmosphere. The observation was limited to about 2-3 km altitude by the presence of clouds over most of the trip.

A camera fixed on the roof of the car “confirms” the LIDAR measurements, as follows:

Spatio-temporal series LIDAR obtained between Lille and Valence on 28/03/2016