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| Titel |
The importance of moisture distribution for the growth and energetics of mid-latitude systems |
| VerfasserIn |
V. Pavan, N. Hall, P. Valdes, M. Blackburn |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 17, no. 2 ; Nr. 17, no. 2, S.242-256 |
| Datensatznummer |
250013676
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| Publikation (Nr.) |
 copernicus.org/angeo-17-242-1999.pdf |
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| Zusammenfassung |
A primitive equation model is used to study
the sensitivity of baroclinic wave life cycles to the initial latitude-height
distribution of humidity. Diabatic heating is parametrized only as a consequence
of condensation in regions of large-scale ascent. Experiments are performed in
which the initial relative humidity is a simple function of model level, and in
some cases latitude bands are specified which are initially relatively dry. It
is found that the presence of moisture can either increase or decrease the peak
eddy kinetic energy of the developing wave, depending on the initial moisture
distribution. A relative abundance of moisture at mid-latitudes tends to weaken
the wave, while a relative abundance at low latitudes tends to strengthen it.
This sensitivity exists because competing processes are at work. These processes
are described in terms of energy box diagnostics. The most realistic case lies
on the cusp of this sensitivity. Further physical parametrizations are then
added, including surface fluxes and upright moist convection. These have the
effect of increasing wave amplitude, but the sensitivity to initial conditions
of relative humidity remains. Finally, 'control' and 'doubled CO2'
life cycles are performed, with initial conditions taken from the time-mean
zonal-mean output of equilibrium GCM experiments. The attenuation of the wave
resulting from reduced baroclinicity is more pronounced than any effect due to
changes in initial moisture.
Key words. Meteorology and atmospheric dynamics
(climatology; convective processes; synoptic-scale meteorology) |
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