Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 9 5 2009 10.5194/acpd-9-18965-2009 http://www.atmos-chem-phys-discuss.net/9/18965/2009/ http://www.atmos-chem-phys-discuss.net/9/18965/2009/acpd-9-18965-2009.html http://www.atmos-chem-phys-discuss.net/9/18965/2009/acpd-9-18965-2009.pdf 18965 18984 2009-09-11 Measurements of coarse mode and primary biological aerosol transmission through a tropical forest canopy using a dual-channel fluorescence aerosol spectrometer A. M. Gabey andrew.m.gabey@postgrad.manchester.ac.uk M. W. Gallagher J. Whitehead J. Dorsey Centre for Atmospheric Science, University of Manchester, Manchester M13 9PL, UK Aerosol in the size range 0.8–20 μm was characterized according to optical equivalent diameter, <i>D</i><sub><i>P</i></sub>, morphology and the presence of biological material, the latter determined by recording fluorescence excited by ultraviolet light pulses at two different wavelengths. Single-particle measurements were performed within and subsequently above a tropical rainforest in Borneo, Malaysia, in June and July 2008. In both locations the aerosol number size distribution exhibited a primary biological aerosol (PBA) mode sized 2 μm<<i>D</i><sub><i>P</i></sub><20 μm and much larger in number within the forest than above it, suggesting the PBA originates below the canopy. PBA was observed to dominate the total number at <i>D</i><sub><i>P</i></sub>>2 μm and possessed a wider morphological range than non-PBA. It also accounted for around 80% of the total number in the understory and 40% of the total number above canopy. Canopy transmission efficiencies for the total aerosol number and PBA are calculated to be 0.48&plusmn;0.19 and 0.31&plusmn;0.15 respectively, with the former appearing to peak during the daytime because of a lack of PBA emission below the canopy. Agranovski, V. and Ristovski, Z. D.: Real-time monitoring of viable bioaerosols: capability of the UVAPS to predict the amount of individual microorganisms in aerosol particles, J. Aerosol Sci., 36, 665–676, 2005. Diehl, K., Quick, C., Matthias-Maser, S., Mitra, S. K., and Jaenicke, R.: The ice nucleating ability of pollen Part I: Laboratory studies in deposition and condensation freezing modes, J. ATMOS RES, 75–87, 2001. Diehl, K., Quick, C., Matthias-Maser, S., Mitra, S. K., and jaenicke, R.: The ice nucleating ability of pollen Part II: Laboratory studies in immersion and contact freezing modes, J. Atmos. Res., 75–87, 2002. Elbert, W., Taylor, P. E., Andreae, M. O., and Pöschl, U.: Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions, Atmos. Chem. Phys., 7, 4569–4588, 2007. Gilbert, G. S. and Reynolds, D. R.: Nocturnal Fungi: Airborne Spores in the Canopy and Understory of a Tropical Rain Forest, Biotropica, 37, 462–464, 2005. Hewitt, C. N., Lee, J., Barkley, M. P., Chappell, N. A., Coe, H., Collier, C., Commane, R., DiCarlo, P., Edwards, P. M., Evans, M. J., Furneaux, K. L., Gallagher, M., Guenther, A., Heard, D. E., Ingham, T., Irwin, M., Langford, B., Lim, S. F., MacDonald, S., MacKenzie, A. R., Mahajan, A., McFiggans, G., Mills, G., Misztal, P., Monks, P. S., Nemitz, E., Nicolas-Perea, V., Oetjen, H., Oram, D., Palmer, P. I., Plane, J. M. C., Pyle, J. A., Reeves, C. E., Robinson, N. H., Stewart, D., Stone, D., and Whalley, L. K.: Oxidant and particle photochemical processes above a south-east Asian tropical rain forest (the OP3 project): rationale, location characteristics, tools and overview, submitted to Atmos. Chem. Phys. Discuss., 2009. Jaenicke, R. and Matthias-Maser, S.: The direct contribution of the biosphere to the atmospheric aerosol, Aerosol Sci., 24, 537–538, 1993. Kaye, P. H., Stanley, W. R., and Hirst, E.: Single particle multichannel bio-aerosol fluorescence sensor, Optics Express, 13, 3583–3593, 2005. Kruijt, B., Malhi, Y., Lloyd, J., Norbre, A. D., Miranda, A. C., Pereira, M. G. P., Culf, A., and Grace, J.: Turbulence Statistics Above And Within Two Amazon Rain Forest Canopies, Bound.-Lay. Meteorol., 94, 297–331, 2000. Lowman, M. and Rinker, H. B.: Forest canopies, 2 ed., Academic Press, 2004. Marsh, C. W. and Greer, A. G.: Forest Land-Use in Sabah, Malaysia – an Introduction to Danum Valley, Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 335, 331–339, 1992. Matthias-Maser, S., Reichert, K., and Jaenicke, R.: Primary Biological Aerosol Particles at the High Alpine Site of Jungfraujoch/Switzerland, Aerosol Sci., 31, 955–956, 1999. Mayaux, P., Achard, F. R., and Malingreau, J.-P.: Global tropical forest area measurements derived from coarse resolution satellite imagery: a comparison with other approaches, Environ. Conser., 25, 37–52, 1998.