Marine Organics and Sea Spray Aerosol Water Uptake Colin O’Dowd, Aditya Vaishya, Darius Ceburnis, Jakub Bialek and Jurgita Ovadnevaite Maria Cristina Facchini, Matteo Rinaldi, Salvatore Marullo, Rosalia Santoleri

Primary Organic Matter Plumes over the NE Atlantic Sea Spray is observed to be enriched in water insoluble organic matter. Enrichment is associated with primary productivity proxys such as Chlorophyll-a. The organic matter has a unique mass spectral fingerprint and is not anthropogenic. Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Ovadnevaite, J., C. O’Dowd, M. Dall’Osto, D. Ceburnis, D. R. Worsnop, and H. Berresheim (2011), Detecting high contributions of primary organic matter to marine aerosol: A case study, Geophys. Res. Lett., 38, LXXXXX, 30 doi:10.1029/2010GL046083.

Seasonality in Organic Matter Enrichment and Productivity Proxies Mace Head is also an important location for monitoring regional scale air pollution levels and changes over O’Dowd et al., Marine Productivity, Viruses, and Aerosolization of Organic Matter - Phytoplankton Dance or Death Disco? Submitted to Science, 2014

Correlation between Organic Enrichment and Proxies at different timescales Mace Head is also an important location for monitoring regional scale air pollution levels and changes over O’Dowd et al., Marine Productivity, Viruses, and Aerosolization of Organic Matter - Phytoplankton Dance or Death Disco? Submitted to Science, 2014

Sea Spray Hygroscopicity and CCN activation Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Ovadnevaite, J., D. Ceburnis, G. Martucci, J. Bialek, C. Monahan, M. Rinaldi, M. C. Facchini, H. Berresheim, D. R. Worsnop, and C. O’Dowd (2011), Primary marine organic aerosol: A dichotomy of low hygroscopicity and high CCN activity, Geophys. Res. Lett., 38, L21806, doi:10.1029/2011GL048869.

Sea Spray Impact on Clouds Mace Head is also an important location for monitoring regional scale air pollution levels and changes over During organic spray explosions, the spray has low hygroscopicity at RH<100% but are super efficient CCN, more than sea salt or sulphates, leading to large increases in cloud droplet concentrations. More that 400 cm-3!!!! Ovadnevaite, J., D. Ceburnis, G. Martucci, J. Bialek, C. Monahan, M. Rinaldi, M. C. Facchini, H. Berresheim, D. R. Worsnop, and C. O’Dowd (2011), Primary marine organic aerosol: A dichotomy of low hygroscopicity and high CCN activity, Geophys. Res. Lett., 38, L21806, doi:10.1029/2011GL048869.

Wind-Driven Sea Spray contributions to wintertime marine AOD AOD is largely determined by primary spray production (∼U2) and water uptake. Shown left is AOD v Wind speed in Wintertime. Spray is predominantly sea salt with associated hygroscopicity. Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Mulcahy, J. P., C. D. O’Dowd, S. G. Jennings, and D. Ceburnis (2008), Significant enhancement of aerosol optical depth in marine air under high wind conditions, Geophys. Res. Lett., 35, L16810, doi:10.1029/2008GL034303

Scattering Coefficient in Low (Winter) and High (Summer) Biological Activity Scattering is also found to be dependent on ∼U2. Scattering properties for the LBA-period are approximately twice those of the HBA-period. 96% of the LBA-HBA scattering difference can be explained by the combined effects of size distribution and refractive index differences. 70% of the scattering difference can be attributed to a difference in refractive index alone resulting from organic-matter enrichment during the HBA period. Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Vaishya, A., S. G. Jennings, and C. O’Dowd (2012), Wind-driven influences on aerosol light scattering in north-east Atlantic air, Geophys. Res. Lett., 39, L05805, doi:10.1029/ 2011GL050556.

Organic Enrichment, Hygroscopicity & Scattering Enhancement Sea-salt hygroscopic growth factor Scattering reduction due to hygroscopicity reduction Organic sea spray low hygroscopic growth factor Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Vaishya, A., J. Ovadnevaite, J. Bialek, S. G. Jennings, D. Ceburnis, and C. D. O’Dowd (2013), Bistable effect of organic enrichment on sea spray radiative properties, Geophys. Res. Lett., 40, doi:10.1002/2013GL058452.

Bistable Hygroscopicity – needs to be Parameterised Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Vaishya, A., J. Ovadnevaite, J. Bialek, S. G. Jennings, D. Ceburnis, and C. D. O’Dowd (2013), Bistable effect of organic enrichment on sea spray radiative properties, Geophys. Res. Lett., 40, doi:10.1002/2013GL058452.

Bistable Scattering & Impact on Direct Radiative Effects TOA Direct Radiative Forcing (∆F) calculated using Haywood & Shine with additional assumptions of marine boundary layer aerosol comprising sea spray at four windspeeds and size distribution between 100 nm and 500 nm with varying organic enrichment. BL height 1000 m Assumed constant RH=90% Mace Head is also an important location for monitoring regional scale air pollution levels and changes over Vaishya, A., J. Ovadnevaite, J. Bialek, S. G. Jennings, D. Ceburnis, and C. D. O’Dowd (2013), Bistable effect of organic enrichment on sea spray radiative properties, Geophys. Res. Lett., 40, doi:10.1002/2013GL058452.

Conclusions LIDAR network Organic Matter enriches sub-micron sea-spray, at times >90%; Under sub-saturation RH, sea-spray enriched in OM has low hygroscopicity OM reduces the scattering efficiency and direct radiative effect of sea-spray; Under supersaturation, sea-spray nulei are super-efficient CCN; Satellites required to elucidate the direct and indirect effect. Trend monitoring is mainly conducted at the Mace Head research station on the west coast: the main activities are as listes.