Posted by Atsuhiko Isobe on November 10, 2000 at 02:47:20:
In Reply to: one-layer / two-layer response fundamentally different posted by Watts on November 09, 2000 at 15:22:44:
Prof. Randy Watts
Thank you very much for your concerns with our work.
In this study, gisostasyh is used for a state of motionless in the lower layer.
Figures 5 and 8 represent the results in the two-layer model.
As you know, as far as the annual cycle (much less than the time taken for the baroclinic Rossby-wave to cross the ocean) is concerned, the variation in the WBC's volume transport is determined by the 'topographic Sverdrup transport'. For such a short timescale, wind-forced baroclinic Rossby-waves have very little effect on the variation of the volume transport at midlatitude (Anderson and Corry, 1985; maybe you suggested this work). Thus, annual variation can be reproduced in the one-layer model with topography (e.g., Greatbatch and Goulding, 1989; Greatbatch and Goulding, 1990; Kubota et al., 1995).
However, when we have active two layers in the model, and when we impose bottom topography, range and phase of the annual variation are changed by the baroclinicity. For instance, in the case of the Florida Strait, annual range of the volume transport is amplified by the baroclinic Kelvin wave passing over the topography (Anderson and Corry, 1985). In the case of the Kuroshio, we would like to emphasize the process in which the annual cycle of the volume transport is controlled by the baroclinic activity generated above the Izu-Ogasawara Ridge.
Reference
Anderson and Corry, J.P.O.,15, 773-786, 1985.
Greatbatch and Goulding, J.P.O., 19, 572-595, 1989
Greatbatch and Goulding, J.Oceanogr. Soc. Japan, 46, 9-20, 1990
Kubota et al., J. Oceanogr. 51, 441-458, 1995
: As you show in Fig 7, the response of your model rectangular
: basin to the annual march of wind-curl forcing is
: (a) for 1-layer, almost immediately adjusted to Sverdrup transport;
: (b) for 2-layers, significantly phase-offset and amplitude-changed
: from Sverdrup transport.
: (Reminiscent of Florida Straits, where phase offset is roughly 180 degrees,
: with max transport in summer, as I recall.)
: As you know, the difference arises from the fast barotropic vs slow
: baroclinic planetary wave propagation speed, which carries the information to
: the western boundary from the central ocean.
: Please indicate whether your Figures 5 and 8 represent a 1- or 2-layer case.
: --interesting poster! --Randy