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| Titel |
Data assimilation for plume models |
| VerfasserIn |
C. A. Majumder, E. Bélanger, S. DeRosier, D. A. Yuen, A. P. Vincent |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 12, no. 2 ; Nr. 12, no. 2 (2005-02-09), S.257-267 |
| Datensatznummer |
250010488
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| Publikation (Nr.) |
 copernicus.org/npg-12-257-2005.pdf |
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| Zusammenfassung |
| We use a four-dimensional variational data assimilation (4D-VAR)
algorithm to observe the growth of 2-D plumes from a point heat
source. In order to test the predictability of the 4D-VAR technique
for 2-D plumes, we perturb the initial conditions and compare the
resulting predictions to the predictions given by a direct numerical
simulation (DNS) without any 4D-VAR correction. We have studied
plumes in fluids with Rayleigh numbers between 106 and 107 and
Prandtl numbers between 0.7 and 70, and we find the quality of the
prediction to have a definite dependence on both the Rayleigh and
Prandtl numbers. As the Rayleigh number is increased, so is the
quality of the prediction, due to an increase of the inertial effects
in the adjoint equations for momentum and energy. The horizon
predictability time, or how far into the future the 4D-VAR method can
predict, decreases as Rayleigh number increases. The quality of the
prediction is decreased as Prandtl number increases, however. Quality
also decreases with increased prediction time. |
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