Evidence for marine biogenic influence on summertime Arctic aerosol
International audience We present vertically-resolved observations of aerosol composition during pristine summertime Arctic background conditions. The methansulfonic acid (MSA)-to-sulfate ratio peaked near the surface (mean 0.10), indicating a contribution from ocean-derived biogenic sulfur. Similar...
Published in: | Geophysical Research Letters |
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Main Authors: | , , , , , , , , , , , |
Other Authors: | , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2017
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Subjects: | |
Online Access: | https://insu.hal.science/insu-01539519 https://insu.hal.science/insu-01539519v1/document https://insu.hal.science/insu-01539519v1/file/2017GL073359.pdf https://doi.org/10.1002/2017gl073359 |
Summary: | International audience We present vertically-resolved observations of aerosol composition during pristine summertime Arctic background conditions. The methansulfonic acid (MSA)-to-sulfate ratio peaked near the surface (mean 0.10), indicating a contribution from ocean-derived biogenic sulfur. Similarly, the organic aerosol (OA)-to-sulfate ratio increased towards the surface (mean 2.0). Both MSA-to-sulfate and OA-to-sulfate ratios were significantly correlated with FLEXPART-WRF-predicted airmass residence time over open water, indicating marine influenced OA. External mixing of sea salt aerosol from a larger number fraction of organic, sulfate and amine-containing particles, together with low wind speeds (median 4.7 m s −1 ), suggests a role for secondary organic aerosol formation. Cloud condensation nuclei concentrations were nearly constant (∼120 cm −3 ) when the OA fraction was <60% and increased to 350 cm −3 when the organic fraction was larger and residence times over open water were longer. Our observations illustrate the importance of marine-influenced OA under Arctic background conditions, which are likely to change as the Arctic transitions to larger areas of open water. |
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