Max Planck Institute for Chemistry P.O. Box 3060 Biogeochemistry Department D Mainz, Germany Manaus plume tracking LBA-Claire 2001 Manaus Fligh track Overview : The aim of the experiment was 1.To evaluate the impact of anthropogenic emissions (Ozone, CN, …) on the biogenic VOCs emissions 2. To better describe the vertical profiles of CN & CCN in remote areas over the tropical forest Overview of the MINOS Campaign : Aerosol optical properties derived from the Advanced Very High Resolution Radiometer (AVHRR) pointed out the Mediterranean Sea as one of the areas with the highest Aerosol optical depths in the world (Husar et al., 1997). Importance of satellite derived measurements to describe the aerosol loads above the Mediterranean was also demonstrated by Moulin et al. (1997) who reported that year-to-year changes in Aerosol optical depths in Mediterranean were driven by African dust and was closely related to air masses circulation and the Northern Oscillation Index. Recent model studies reproduced satellite observations and demonstrated the role of three major components of aerosols in surrounding regions of the Mediterranean basin (sulfate, black carbon and dust), having very high direct radiative forcing of aerosols at the top of the atmosphere (Jacobsen, 2001). This model estimates a negative radiative forcing for aerosols in Mediterranean, which could compare with greenhouse gases (e.g. -3 to -4 W/m²). Thus, transport of aerosols and their precursors from these regions will have dramatic impact not only on radiative properties over the Mediterranean Sea but even on cloud properties. Rosenfeld (2000) showed that Turkish power plants using high sulfur containing lignite were identified from satellite-derived pictures as influencing downwind cloud radius droplets. As a matter of fact, the most complete characterization of aerosols emitted from each of these regions and reaching the Mediterranean basin will undoubtedly be needed to validate model calculations and remote sensing observations. Jean Sciare Ph-D thesis (LSCE, France, May 2000) Post-doc MPI Mainz (2001) / Biogeochemistry (M.O. Andreae) CR2 – CNRS, LSCE, France (since October 2001) Acknowledgements : I would like to address grateful thanks to Prof. Dr. M.O. Andreae who accepted to review my Ph-D thesis and who accepted me in his group in Mainz for a post-doctoral position. Thanks to the results obtained during my Ph-D and during my post-doc in Mainz I obtained in October 2001 a permanant position at CNRS. Many thanks go also to my co-workers (Greg, Olga, Pascal and Bim) who made to my stay in Mainz an unforgotable memory. Large discrepancies between the 2 techniques Long-range transport of soot aerosols over the Eastern Mediterranean Basin Calculations were performed using hourly 5-day backtrajectories From Hysplit 4.0 model (FNL data) FINOKALIA STATION MINOS campaign Environmental Chemical Processes Laboratory Air masses origin during the Minos campaign (25/07-25/08/01) Instruments Calibration  T = 5°C  Supersaturation  1% Humid plates Laser beam Air Video acquisition Principle Instrument developped in Mainz by G. Robert CCN counter: settings / calibration PhotoAcoustic System (PAS) A 670 nm photodiode laser illumaniates the activated droplets while the digital camera, normal to the laser beam, registers digital images every second during the supersaturation cycle. The CCN concentration at a particular supersaturation is calculated by imaging sofware, which automatically determines the number of activated droplets in each picture (extracted from G. Roberts Ph-D dissertation) Principle : CCN measurements are made using a static thermal- gradient diffusion instrument. It is fitted with a photodiode laser and digital camera to measure droplet concentrations. Activated CCN particles quickly grow to several micrometers in diameter and gravitationally settle out of the chamber. Principle : An alternative to filter-based methods for light absorption measurement is to use a photoacoustic instrument. No filters are used in these intruments, but instead, the sample air can be continuously drawn through a acoustical waveguide. A periodically modulated laser beam passes through the waveguide. Concomitant with light absorption by either gas or particles is heat transfer to the surrounding air. The waveguide can be designed at a frequency such that all the heat from light absorption is transferred during the period of oscillation. upon receiving this heat, from light absorption, the surrounding air expands and this expansion contributes to the acoustic standing wave in the waveguide. Measurement is made with a microphone. The microphone is linearly proportional to the aerosol light absorption coefficient. (extracted from Arnott et al., 2001) Aerosol absorption Noise of the instrument Aerosol free air AB Manaus Ratio CCN/CN ~10% Plume of pollution located in the PBL Well-mixed plume within the first hundreds meters Plume Study (Flight 18 – 19/07/01) Vertical profile (Flight 15 – 18/07/01) Ratio CCN/CN ~50-60%