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Titel |
On direct passive microwave remote sensing of sea spray aerosol production |
VerfasserIn |
I. B. Savelyev, M. D. Anguelova, G. M. Frick, D. J. Dowgiallo, P. A. Hwang, P. F. Caffrey, J. P. Bobak |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 21 ; Nr. 14, no. 21 (2014-11-05), S.11611-11631 |
Datensatznummer |
250119139
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Publikation (Nr.) |
copernicus.org/acp-14-11611-2014.pdf |
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Zusammenfassung |
This study addresses and attempts to mitigate persistent uncertainty and
scatter among existing approaches for determining the rate of sea spray
aerosol production by breaking waves in the open ocean. The new approach
proposed here utilizes passive microwave emissions from the ocean surface,
which are known to be sensitive to surface roughness and foam. Direct,
simultaneous, and collocated measurements of the aerosol production and
microwave emissions were collected aboard the FLoating Instrument
Platform (FLIP) in deep water ~ 150 km off the coast of California over
a period of ~ 4 days. Vertical profiles of coarse-mode aerosol
(0.25–23.5 μm) concentrations were measured with a forward-scattering
spectrometer and converted to surface flux using dry deposition
and vertical gradient methods. Back-trajectory analysis of eastern North Pacific
meteorology verified the clean marine origin of the sampled air mass over at
least 5 days prior to measurements. Vertical and horizontal polarization
surface brightness temperature were measured with a microwave radiometer at
10.7 GHz frequency. Data analysis revealed a strong sensitivity of the
brightness temperature polarization difference to the rate of aerosol
production. An existing model of microwave emission from the ocean surface
was used to determine the empirical relationship and to attribute its
underlying physical basis to microwave emissions from surface roughness and
foam within active and passive phases of breaking waves. A possibility of
and initial steps towards satellite retrievals of the sea spray aerosol
production are briefly discussed in concluding remarks. |
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