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| Titel |
Adjoint sensitivity of global cloud droplet number to aerosol and dynamical parameters |
| VerfasserIn |
V. A. Karydis, S. L. Capps, A. G. Russell, A. Nenes |
| 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 ; 12, no. 19 ; Nr. 12, no. 19 (2012-10-04), S.9041-9055 |
| Datensatznummer |
250011493
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| Publikation (Nr.) |
 copernicus.org/acp-12-9041-2012.pdf |
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| Zusammenfassung |
| We present the development of the adjoint of a comprehensive cloud droplet
formation parameterization for use in aerosol-cloud-climate
interaction studies. The adjoint efficiently and accurately calculates the
sensitivity of cloud droplet number concentration (CDNC) to all
parameterization inputs (e.g., updraft velocity, water uptake
coefficient, aerosol number and hygroscopicity) with a single
execution. The adjoint is then integrated within three
dimensional (3-D) aerosol modeling frameworks to quantify the
sensitivity of CDNC formation globally to each
parameter. Sensitivities are computed for year-long executions of
the NASA Global Modeling Initiative (GMI) Chemical Transport Model
(CTM), using wind fields computed with the Goddard Institute for
Space Studies (GISS) Global Circulation Model (GCM) II',
and the GEOS-Chem CTM, driven by meteorological input from the
Goddard Earth Observing System (GEOS) of the NASA Global Modeling
and Assimilation Office (GMAO). We find that over polluted (pristine)
areas, CDNC is more sensitive to updraft velocity
and uptake coefficient (aerosol number and hygroscopicity). Over
the oceans of the Northern Hemisphere, addition of anthropogenic or biomass
burning aerosol is predicted to increase CDNC in contrast to coarse-mode
sea salt which tends to decrease CDNC. Over the Southern Oceans,
CDNC is most sensitive to sea salt, which is the main aerosol
component of the region. Globally, CDNC is predicted to be less
sensitive to changes in the hygroscopicity of the aerosols than in
their concentration with the exception of dust where CDNC is very
sensitive to particle hydrophilicity over arid areas. Regionally,
the sensitivities differ considerably between the two frameworks and
quantitatively reveal why the models differ considerably in their indirect forcing
estimates. |
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