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LOAC (Light Optical Aerosol Counter): a new small balloon-borne aerosol counter/sizer with some particle characterization capabilities J.-B. Renard, G.

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Presentation on theme: "LOAC (Light Optical Aerosol Counter): a new small balloon-borne aerosol counter/sizer with some particle characterization capabilities J.-B. Renard, G."— Presentation transcript:

1 LOAC (Light Optical Aerosol Counter): a new small balloon-borne aerosol counter/sizer with some particle characterization capabilities J.-B. Renard, G. Berthet, F. Jegou, M. Jeannot LPC2E-CNRS, Orléans, France F. Dulac, J. Sciare, J. Nicolas LSCE/CEA, Gif-sur-Yvette, France M. Mallet, P. Durand LA, Toulouse, France C. Thaury, S. Salles, J.-L. Mineau, T. Tonnelier Environnement-SA company, Poissy, France N. Verdier CNES, Toulouse, France P. Charpentier MeteoMODEM company, Ury, France J. Giacomoni Aerophile SA company H. Olafsson Iceland University

2 Different types of aerosols in the troposphere and the stratosphere, having different origins Interplanetary grains Pollution Volcanoes Transported sands Disintegrated meteorites Biomass burning (and pyroconvection)

3 How to study aerosols when not at ground?  From satellites (remote sensing of the atmosphere) - Estimation of aerosols size and nature (using some hypothesis for the data analysis)  Aerosols Lidar measurements from Calipso Extinction from GOMOS/envisat

4 From dedicated aircrafts and from (large) balloons:  - Collecting techniques, optical instruments Aerosol counter STAC operated in the middle atmosphere, below stratospheric balloons Vertical profiles and size distribution … assuming liquid particles (which is not always the case even in the stratosphere)

5 Only sparse in situ measurements and strong constraints:  - High costs (aircrafts and balloons)  - Technical limitations (how to fly during strong volcanic eruption?)  - Need of complex infrastructures (few launching bases in the world for the stratospheric balloons) There is a need for an aerosol counter that can be launched under all kinds of balloons (including meteo balloons) : - Low cost (the instrument can be lost after the flight) - Light instrument - Insensitive to the aerosols nature (accurate determination of size), which is not the case with the usual aerosol counters.

6 LOAC : Light Optical Aerosol Counter Measurements at 2 scattering angles : 12°, where the scattered light is ~ insensitive to the nature of the aerosols 60°, where the scattered light is very sensitive to the nature of the aerosols Combining the measurements => accurate determination of the size distribution => estimation of the main nature of the aerosols Aerosols Laser

7 Collaboration between French research institutes and private companies LOAC was design and tested in our institutes (CNRS and CNES) LOAC is build by Environnement-SA company Gondola and telemetry are build by MeteoMODEM company

8 - 20 size classes between  m - - Optical chamber and pump: weight < 500 g - Can work during 4 hours with 2 alkaline batteries of 4.5 V -Total weigh with gondola for flight under meteo balloon : 1 kg (using meteoMODEM telemetry) Large stratospheric balloon Long duration stratospheric balloon Meteo balloon Low altitude troposheric balloon

9 First version of LOAC (10 copies ): 3 flights under large stratospheric balloons (Sweden and Brazil) 6 flights under meteo balloons (Iceland, France) 9 months onboard a tethered balloon (Touristic balloon “Air de Paris”) 4 LOAC are lost … Improved version of LOAC (20 copies at the end of 2012) 2 test flights under meteo balloon at the end of August 2012 (France)

10 Kiruna, Northern Sweden, 1 April 2011 (large stratospheric balloon, onboard German gondola TWIN, CNES launch) Strong variability of aerosol content

11 West Iceland, 20 July 2011 (meteo balloon, Iceland meteo office launch)  “clean stratosphere”

12 Comparison of the 2 measurements channels at scattering angles of 12° and 60° (size distributions) => identification of the main nature of the aerosols (by comparison to a laboratory data base) The 2 curves are close => liquid aerosols

13 Bauru (Brazil), 13 March 2012 (stratospheric balloon, Reims University “Tropico project”) Several enhancements of “large” particles around 10  m Soot particles ?

14 Sausset-les-Pins (France), 28 June 2012 (meteo balloon, CNES) 2 flights during an episode of sand above Mediterranean sea Size grains in the 5-30  m range

15 At ground, liquid aerosols (launch on the beach) On the middle troposphere, sand Data Carbon Mineral Droplets Data Carbon Mineral Droplets

16  LOAC is involved in several projects: Mid-september 2012 : tests of the new version of LOAC during sand events, meteo balloon (Meteo France) Winter : ParisFog campaign, study of fog, tethered balloon (SIRTA – meteo France) Beginning of 2013: Tests onboard low altitude tropospheric balloons “BPCL” (CNES) Summer 2013: Charmex campaign, study of aerosols transport above Mediterranean sea, BPCL and meteo ballons (CNES) End of 2013: Aerowave campaign, stratospheric aerosols, large stratospheric balloons (CNES) … 2018 : Strateole phase 2, tens of long-duration stratospheric balloons above equatorial regions


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