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| Titel |
Ground-based retrieval of continental and marine warm cloud microphysics |
| VerfasserIn |
G. Martucci, C. D. O'Dowd |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 4, no. 12 ; Nr. 4, no. 12 (2011-12-15), S.2749-2765 |
| Datensatznummer |
250002151
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| Publikation (Nr.) |
 copernicus.org/amt-4-2749-2011.pdf |
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| Zusammenfassung |
| A technique for retrieving warm cloud microphysics using synergistic ground
based remote sensing instruments is presented. The SYRSOC (SYnergistic
Remote Sensing Of Cloud) technique utilises a Ka-band Doppler cloud RADAR,
a LIDAR (or ceilometer) and a multichannel microwave radiometer. SYRSOC
retrieves the main microphysical parameters such as cloud droplet number
concentration (CDNC), droplets effective radius (reff), cloud liquid
water content (LWC), and the departure from adiabatic conditions within the
cloud. Two retrievals are presented for continental and marine stratocumulus
advected over the Mace Head Atmospheric Research Station. Whilst the
continental case exhibited high CDCN (N = 382 cm−3;
10th-to-90th percentile [9.4–842.4] cm−3) and small mean
effective radius (reff = 4.3; 10th-to-90th
percentile [2.9–6.5] μm), the marine case showed low CDNC and large
mean effective radius (N = 25 cm−3, 10th-to-90th
percentile [1.5–69] cm−3; reff = 28.4 μm,
10th-to-90th percentile [11.2–42.7] μm) as expected since
continental air at this location is typically more polluted than marine air.
The mean LWC was comparable for the two cases (continental: 0.19 g m−3;
marine: 0.16 g m−3) but the 10th–90th percentile range was
wider in marine air (continental: 0.11–0.22 g m−3; marine: 0.01–0.38 g m−3).
The calculated algorithm uncertainty for the continental and
marine case for each variable was, respectively, σN = 161.58 cm−3
and 12.2 cm−3, σreff = 0.86 μm and 5.6 μm,
σLWC = 0.03 g m−3 and 0.04 g m−3. The retrieved
CDNC are compared to the cloud condensation nuclei concentrations and the
best agreement is achieved for a supersaturation of 0.1% in the
continental case and between 0.1%–0.75% for the marine stratocumulus.
The retrieved reff at the top of the clouds are compared to the MODIS
satellite reff: 7 μm (MODIS) vs. 6.2 μm (SYRSOC) and
16.3 μm (MODIS) vs. 17 μm (SYRSOC) for continental and marine cases,
respectively. The combined analysis of the CDNC and the reff, for the
marine case shows that the drizzle modifies the droplet size distribution
and reff especially if compared to reffMOD. The study of the cloud subadiabaticity and the LWC shows the general
sub-adiabatic character of both clouds with more pronounced departure from
adiabatic conditions in the continental case than in the marine. |
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