Marine Organics and Sea Spray Aerosol Water UptakeColin 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.

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.

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Seasonality in Organic Matter Enrichment and Productivity Proxies

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

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

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

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

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

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.

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.

Vaishya, A., S. G. Jennings, and C. O’Dowd (2012), Wind-driven influences on aerosol light scattering in north-eastAtlantic air, Geophys. Res. Lett., 39, L05805, doi:10.1029/ 2011GL050556.

•Organic Enrichment, Hygroscopicity & Scattering Enhancement

Scattering reduction due to hygroscopicity reduction

• Sea-salt hygroscopic growth factor

• Organic sea spray low hygroscopic growth factor

Vaishya, A., J. Ovadnevaite, J. Bialek, S. G. Jennings, D. Ceburnis, and C. D. O’Dowd (2013), Bistable effect of organicenrichment on sea spray radiative properties, Geophys. Res. Lett., 40, doi:10.1002/2013GL058452.

•Bistable Hygroscopicity – needs to be Parameterised

Vaishya, A., J. Ovadnevaite, J. Bialek, S. G. Jennings, D. Ceburnis, and C. D. O’Dowd (2013), Bistable effect of organicenrichment on sea spray radiative properties, Geophys. Res. Lett., 40, doi:10.1002/2013GL058452.

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•Bistable Scattering & Impact on Direct Radiative Effects

Vaishya, A., J. Ovadnevaite, J. Bialek, S. G. Jennings, D. Ceburnis, and C. D. O’Dowd (2013), Bistable effect of organicenrichment on sea spray radiative properties, Geophys. Res. Lett., 40, doi:10.1002/2013GL058452.

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 mAssumed constant RH=90%

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.

Conclusions