Eric BOURRIANNE LPC2E - CNRS, ORLEANS Characterization of the size distribution and nature of the particles detected by the LOAC aerosol counters under tropospheric pressurized balloons Eric BOURRIANNE LPC2E - CNRS, ORLEANS

LOAC under BPCL for ChArMEx BPCL : Boundary Layer Pressurized Balloons (Quasi-Lagrangian measurements) 12 flights have been performed from Minorca and Ile du Levant SOP-2 SOP-1 We focus here on 4 different situations : Background measurements Sand events Salt detection Carbon detection

ChArMEx-S1-B76 – 2 July 2013 Background condition -o- BPCL -o- BLD ascent Background condition Changes in the balloon altitude due to the day-night transition Presence of large particles (> 20 µm)

Background condition in the first part of the flight ALADIN model 2 July 2013, 18UT Undefined ALADIN model 2 July 2013, 42UT Background condition in the first part of the flight Sand measurements for the second par of the flight (Non-lagrangian measurements due to variation of the balloon altitude)

Cross-comparison between BPCL and BLD (meteo balloon) measurements at same altitude Size distribution Speciation Very good agreement for the size distribution and for the indication of the nature of the aerosols (no homogenous nature in this case)

ChArMEx-S1-B74 – 16 June 2013 – Sand event -o- BPCL -o- BLD Presence of large particles (up to 50 µm) No strong evolution of the size distribution during the flight

The LOAC speciation seems to indicate mixture of sand and salt. ALADIN model, 16 June 2013, 12UT The LOAC speciation seems to indicate mixture of sand and salt.

Cross-comparison between BPCL and BLD (meteo balloon) measurements at same altitude Size distribution Speciation Good agreement between BPCL and BLD Speciation : Sand for particles > 2µm, sand and/or salt for particles < 2µm

ChArMEx-S1-B75 – 17 June 2013 – Sand event -o- BPCL -o- BLD Presence of large particles (up to 50 µm) No strong evolution of the size distribution during the flight

ChArMEx-S2-B51– 22and23 July 2013 – -o- BPCL -o- BLD low altitude flight (400m) Detection of salt particles for all sizes Constant concentrations all along the flight

ChArMEx-S1-B80– 28 June 2013 Possible detection of the biomass burning plume

Conclusions Main results : Very good agreement between the BPCL and BLD LOAC measurement at similar time and altitude LOAC as detected different natures of particles depending on the flights Detection of large sand particles even after several day of transport No sedimentation detected during the BPCL flights