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| Titel |
Diagnosing the average spatio-temporal impact of convective systems – Part 2: A model intercomparison using satellite data |
| VerfasserIn |
M. S. Johnston, S. Eliasson, P. Eriksson, R. M. Forbes, A. Gettelman, P. Räisänen, M. D. Zelinka |
| 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. 16 ; Nr. 14, no. 16 (2014-08-26), S.8701-8721 |
| Datensatznummer |
250118979
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| Publikation (Nr.) |
 copernicus.org/acp-14-8701-2014.pdf |
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| Zusammenfassung |
The representation of the effect of tropical deep convective (DC) systems on
upper-tropospheric moist processes and outgoing longwave radiation is
evaluated in the EC-Earth3, ECHAM6, and CAM5 (Community Atmosphere Model) climate models using
satellite-retrieved data. A composite technique is applied to thousands of
deep convective systems that are identified using local rain rate maxima in
order to focus on the temporal evolution of the deep convective processes in
the model and satellite-retrieved data.
The models tend to over-predict the occurrence of rain rates that are less
than ≈ 3 mm h−1 compared to Tropical Rainfall Measurement
Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA). While the diurnal
distribution of oceanic rain rate maxima in the models is similar to the
satellite-retrieved data, the land-based maxima are out of phase.
Despite having a larger climatological mean upper-tropospheric relative
humidity, models closely capture the satellite-derived moistening of the
upper troposphere following the peak rain rate in the deep convective
systems. Simulated cloud fractions near the tropopause are larger than in the
satellite data, but the ice water contents are smaller compared with the
satellite-retrieved ice data. The models capture the evolution of ocean-based
deep convective systems fairly well, but the land-based systems show
significant discrepancies. Over land, the diurnal cycle of rain is too
intense, with deep convective systems occurring at the same position on
subsequent days, while the satellite-retrieved data vary more in timing and
geographical location.
Finally, simulated outgoing longwave radiation anomalies associated with deep
convection are in reasonable agreement with the satellite data, as well as
with each other. Given the fact that there are strong disagreements with, for
example, cloud ice water content, and cloud fraction, between the models, this
study supports the hypothesis that such agreement with satellite-retrieved
data is achieved in the three models due to different representations of deep
convection processes and compensating errors. |
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