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Titel |
Using surface remote sensors to derive radiative characteristics of Mixed-Phase Clouds: an example from M-PACE |
VerfasserIn |
G. Boer, W. D. Collins, S. Menon, C. N. Long |
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 ; 11, no. 23 ; Nr. 11, no. 23 (2011-12-02), S.11937-11949 |
Datensatznummer |
250010230
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Publikation (Nr.) |
copernicus.org/acp-11-11937-2011.pdf |
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Zusammenfassung |
Measurements from ground-based cloud radar, high spectral resolution lidar
and microwave radiometer are used in conjunction with a column version of the
Rapid Radiative Transfer Model (RRTMG) and radiosonde measurements to derive
the surface radiative properties under mixed-phase cloud conditions. These
clouds were observed during the United States Department of Energy (US DOE)
Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Clouds Experiment
(M-PACE) between September and November of 2004. In total, sixteen half hour
time periods are reviewed due to their coincidence with radiosonde launches.
Cloud liquid (ice) water paths are found to range between 11.0–366.4
(0.5–114.1) gm−2, and cloud physical thicknesses fall between
286–2075 m. Combined with temperature and hydrometeor size estimates, this
information is used to calculate surface radiative flux densities using
RRTMG, which are demonstrated to generally agree with measured flux densities
from surface-based radiometric instrumentation. Errors in longwave flux
density estimates are found to be largest for thin clouds, while shortwave
flux density errors are generally largest for thicker clouds. A sensitivity
study is performed to understand the impact of retrieval assumptions and
uncertainties on derived surface radiation estimates. Cloud radiative forcing
is calculated for all profiles, illustrating longwave dominance during this
time of year, with net cloud forcing generally between 50 and 90 Wm−2. |
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