 |
| Titel |
Can meridionally propagating inertial waves drive an oscillating zonal mean flow? |
| VerfasserIn |
Torsten Seelig, Uwe Harlander |
| Konferenz |
EGU General Assembly 2015
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104402
|
| Publikation (Nr.) |
 EGU/EGU2015-3823.pdf |
|
|
|
|
|
| Zusammenfassung |
| Zonal mean flow excitation by inertial waves is studied in analogy to mean flow excitation by gravity waves [3]. In geophysical flows that are stratified and rotating, the two classes of waves correspond to the two limiting cases: gravity waves neglect rotation, inertial waves neglect stratification. The former are more relevant for fluids like the atmosphere, where stratification is dominant, the latter for the deep oceans or planet cores, where rotation dominates. In the present study waves are suggested to propagate in the meridional plane. A hierarchy of simple analytical and numerical models is considered and the results are compared with data from a laboratory experiment. The main findings can be summarised as follows: (i) when the waves are decoupled from the mean flow they just drive a retrograde (eastward) zonal mean flow, independent of the sign of the meridional phase speed; (ii) when coupling is present and the zonal mean flow is assumed to be steady, the waves can drive vertically alternating jets, but still, in contrast to the gravity wave case, the structure is independent of the sign of the meridional phase speed; (iii) when coupling is present and time-dependent zonal mean flows are considered the waves can drive vertically and temporarily oscillating mean flows. The comparison with laboratory data from a rotating annulus experiment shows a qualitative agreement. It appears that the experiment captures the basic elements of the inertial wave mean flow coupling. The results might be relevant to understand how the Equatorial Deep Jets can be maintained against dissipation [1, 2], a process currently discussed controversially.
[1] Greatbatch, R., Brandt, P., Claus, M., Didwischus, S., Fu, Y.: On the width of the equatorial deep jets. Journal of Physical Oceanography 42, 1729–1740 (2012)
[2] Muench, J.E., Kunze, E.: Internal wave interactions with equatorial deep jets. Part II: Acceleration of the jets. J. Phys. Oceanogr. 30, 2099–2110 (2000)
[3] Plumb, R.A.: Momentum transport by the thermal tide in the stratosphere of Venus. J. Roy. Meteor. Soc. 101, 763–776 (1975) |
|
|
|
|
|
|