Seasonal characteristics of the physicochemical properties of North Atlantic marine atmospheric aerosols

Abstract

The aerosol size distribution modal diameters show seasonal variations, 0.031 mm in winter and 0.049 mm in summer for the Aitken mode and 0.103 mm in winter and 0.177 mm in summer for the accumulation mode. The accumulation mode mass also showed a seasonal variation, minimum in winter and maximum in summer. A supermicron sized particle mode was found at 2 mm for all seasons showing 30% higher mass concentration during winter than summer resulting from higher wind speed conditions. Chemical analysis showed that the concentration of sea salt has a seasonal pattern, minimum in summer and maximum in winter because of a dependency of sea-salt load on wind speeds. By contrast, the nonsea-salt (nss) sulphate concentration in fine mode particles exhibited lower values during winter and higher values during midsummer. The water soluble organic carbon (WSOC) and total carbon (TC) analysis also showed a distinctive seasonal pattern. The WSOC concentration during the high biological activity period peaked at 0.2 mgC m À3 , while it was lower than 0.05 mgC m À3 during the low biological activity period. The aerosol light scattering coefficient showed a minimum value of 5.5 Mm À1 in August and a maximum of 21 Mm À1 in February. This seasonal variation was due to the higher contribution of sea salt in the MBL during North Atlantic winter. By contrast, aerosols during late spring and summer exhibited larger angstrom parameters than winter, indicating a large contribution of the biogenically driven fine or accumulation modes. Seasonal characteristics of North Atlantic marine aerosols suggest an important link between marine aerosols and biological activity through primary production of marine aerosols.

Composition and evolution of volcanic aerosol from eruptions of Kasatochi, Sarychev and Eyjafjallajökull in 2008–2010 based on CARIBIC observations

“…The activity shows strong geographical and seasonal variations (Stramska, 2009). Measurements in Maze Head (Ireland) show organic aerosol concentration of several hundred ng m −3 connected with biologic activity in the ocean during spring to autumn (O'Dowd et al, 2004;Yoon et al, 2007). All three volcanoes studied here erupted in the biologically active part of the year.…”

Aerosol distribution over Europe: a model evaluation study with detailed aerosol microphysics

“…The net accumulation sea-spray flux is based on Geever et al (2005) and is used as an organic-inorganic source function for the mixture of POC and sea salt aerosols. Recent measurements at the Mace Head station at the Atlantic coast of Ireland (O'Dowd et al, 2004;Yoon et al, 2007) have shown that OC contributes a considerable fraction to seaspray during periods of increased biological activity of the ocean. Further details are given in O' Dowd et al (2008).…”

Marine aerosol production: a review of the current knowledge

“…Increase in sea-salt mass is primarily associated with increasing wind speeds with mass concentrations being measured up to 1000 mg m K3 at wind speeds of 15-20 m s K1 (Lewis & Schwartz 2004). Although mass loadings can be high, marine aerosol number concentrations are typically low, of the order of 300-600 cm K3 (O'Dowd et al 1997;Yoon et al 2007), of which up to 50-150 cm K3 can be sea-salt particles under high wind conditions (O'Dowd & Smith 1993;Kreidenweis et al 1998).…”