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| Titel |
Spatial and temporal variability of clouds and precipitation over Germany: multiscale simulations across the "gray zone" |
| VerfasserIn |
C. Barthlott, C. Hoose |
| 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 ; 15, no. 21 ; Nr. 15, no. 21 (2015-11-09), S.12361-12384 |
| Datensatznummer |
250120147
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| Publikation (Nr.) |
 copernicus.org/acp-15-12361-2015.pdf |
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| Zusammenfassung |
| This paper assesses the resolution dependance of clouds and precipitation
over Germany by numerical simulations with the COnsortium for Small-scale
MOdeling (COSMO) model. Six intensive observation periods of the HOPE
(HD(CP)2 Observational Prototype Experiment) measurement campaign
conducted in spring 2013 and 1 summer day of the same year are simulated.
By means of a series of grid-refinement resolution tests (horizontal grid
spacing 2.8, 1 km, 500, and 250 m), the applicability of the
COSMO model to represent real weather events in the gray zone, i.e., the scale
ranging between the mesoscale limit (no turbulence resolved) and the
large-eddy simulation limit (energy-containing turbulence resolved), is
tested. To the authors' knowledge, this paper presents the first
non-idealized COSMO simulations in the peer-reviewed literature at the
250–500 m scale. It is found that the kinetic energy spectra derived
from model output show the expected −5/3 slope, as well as a dependency on
model resolution, and that the effective resolution lies between 6 and 7
times the nominal resolution. Although the representation of a number of
processes is enhanced with resolution (e.g., boundary-layer thermals,
low-level convergence zones, gravity waves), their influence on the temporal
evolution of precipitation is rather weak. However, rain intensities vary
with resolution, leading to differences in the total rain amount of up to
+48 %. Furthermore, the location of rain is similar for the
springtime cases with moderate and strong synoptic forcing, whereas
significant differences are obtained for the summertime case with air mass
convection. Domain-averaged liquid water paths and cloud condensate profiles
are used to analyze the temporal and spatial variability of the simulated
clouds. Finally, probability density functions of convection-related
parameters are analyzed to investigate their dependance on model resolution
and their impact on cloud formation and subsequent precipitation. |
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