التفاصيل البيبلوغرافية
| العنوان: |
Advective mixing in a nondivergent barotropic hurricane model. |
| المؤلفون: |
Rutherford, B., Dangelmayr, G., Persing, J., Schubert, W. H., Montgomery, M. T. |
| المصدر: |
Atmospheric Chemistry & Physics; 2010, Vol. 10 Issue 2, p475-497, 23p, 1 Diagram, 16 Graphs |
| مصطلحات موضوعية: |
HURRICANES, LAGRANGIAN functions, LAGRANGE spectrum, LYAPUNOV functions, LYAPUNOV stability |
| مستخلص: |
This paper studies Lagrangian mixing in a two-dimensional barotropic model for hurricane-like vortices. Since such flows show high shearing in the radial direction, particle separation across shear-lines is diagnosed through a Lagrangian field, referred to as R-field, that measures trajectory separation orthogonal to the Lagrangian velocity. The shear-lines are identified with the level-contours of another Lagrangian field, referred to as S-field, that measures the average shear-strength along a trajectory. Other fields used for model diagnostics are the Lagrangian field of finite-time Lyapunov exponents (FTLE-field), the Eulerian Q-field, and the angular velocity field. Because of the high shearing, the FTLE-field is not a suitable indicator for advective mixing, and in particular does not exhibit ridges marking the location of finite-time stable and unstable manifolds. The FTLE-field is similar in structure to the radial derivative of the angular velocity. In contrast, persisting ridges and valleys can be clearly recognized in the R-field, and their propagation speed indicates that transport across shear-lines is caused by Rossby waves. A radial mixing rate derived from the Rfield gives a time-dependent measure of flux across the shearlines. On the other hand, a measured mixing rate across the shear-lines, which counts trajectory crossings, confirms the results from the R-field mixing rate, and shows high mixing in the eyewall region after the formation of a polygonal eyewall, which continues until the vortex breaks down. The location of the R-field ridges elucidates the role of radial mixing for the interaction and breakdown of the mesovortices shown by the model. [ABSTRACT FROM AUTHOR] |
|
Copyright of Atmospheric Chemistry & Physics is the property of Copernicus Gesellschaft mbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) |
| قاعدة البيانات: |
Complementary Index |
Full Text Finder