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| Titel |
Depletion of Black Carbon Mass in the Springtime Arctic Boundary Layer |
| VerfasserIn |
Ryan Spackman, Ru-Shan Gao, William Neff, Joshua Schwarz, Laurel Watts, David Fahey, John Holloway, Thomas Ryerson, Jeff Peischl, Charles Brock |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048920
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| Zusammenfassung |
| Understanding the processes controlling black carbon (BC) in the Arctic boundary layer
(ABL) is crucial for evaluating the impact of anthropogenic and natural sources of BC
aerosol on Arctic climate. Vertical profiles of BC mass loadings were performed in the ABL
over the sea-ice in the Alaskan Arctic in April 2008 using a Single-Particle Soot
Photometer (SP2) during flights on the NOAA WP-3D research aircraft. Positive
vertical gradients in BC mass mixing ratios were observed in the ABL over the
sea-ice, generally in the vicinity of open leads. BC mass loadings more than doubled
with increasing altitude within the ABL and across the boundary layer transition
while carbon monoxide (CO) remained constant in the aged Arctic air mass. This is
evidence for depletion of BC mass in the ABL. BC mass loadings were positively
correlated with ozone (O3) in ozone depletion events for all the observations in the
ABL. Since bromine catalytically destroys O3 in the ABL after being released as
molecular bromine in regions of new sea-ice formation at the surface, the BC–O3
correlation suggests that BC particles were removed by a surface process such as dry
deposition. We have developed a box model to estimate the dry deposition flux of BC
mass to the snow constrained by the vertical profiles of BC mass in the ABL. Open
leads in the sea-ice may increase vertical mixing and entrainment of pollution from
the free troposphere possibly enhancing the deposition of BC aerosol to the snow. |
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