Variability of polar flows

• Published in: Journal of Physics: Conference Series
• Main Author: Derzho, Oleg
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: IOP Publishing 2020
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1088/1742-6596/1677/1/012009; https://iopscience.iop.org/article/10.1088/1742-6596/1677/1/012009/pdf; https://iopscience.iop.org/article/10.1088/1742-6596/1677/1/012009

Abstract It is anticipated that the physical mechanism of the variability of polar currents may be attributed to temporal and spatial variations of the cyclonic mean flow due to circularly propagating nonlinear Rossby waves. A low order analytical model for the effect of large scale and low frequency variability of a polar current is presented. Rossby wave packet is shown to be an intrinsic mode of motion trapped between the major flows, which constitute the mean current. The Rossby wave pattern is predicted to rotate with a specific angular velocity, which depends on both the magnitude and width of the time averaged flow. Spatial structure of the rotating pattern, including its zonal wave number, is defined by the specific form of the stream function-vorticity relation. Theoretically predicted patterns capture the main features of the Antarctic Circumpolar Wave (ACW). The model is capable to predict the observed sequence of warm and cold patches in the ACW along with its zonal number.