Barotropic Standing-Progressive Rossby Waves
|Lead Author||Tatyana, Belonenko|
|Institution Contact||Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia|
|Co-Authors||Victor R. Foux Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034 Russia|
|Theme||Theme 1: Vulnerability of Arctic Environments|
|Session Name||1.1 Climate Change and Environmental Management in the Arctic|
|Abstract text||Isopleths (Hovmoller Diagrams) of the sea-level variation on latitudinal or longitudinal sections demonstrate specific points in which the sea level is stationary (nearly zero values of the sea-level heights) for a time interval. A phase discontinuity of the sea-level variation takes place near such points, which results, because of the phase jump, in converting wave crests into troughs. In general, the wave movement pattern may be said to consist of standing-progressive waves, or more specifically, Rossby’s, on accounting their spatial-temporal scales: wavelengths from several kilometers to thousands and periods from several days to several years.
This kinematical model does rather correctly describe wave disturbances in the field of altimetry heights of sea surface. It is possible that such disturbances should satisfy to a system of hydrodynamic equations which describe wave movements of the type of gradient-vortex waves.
In this model at zero moment, in the center of the rectangular cell bounded on all sides by fixed nodal lines there is a wave crest, and on the east and west there are wave troughs. Since a quarter of the cycle, this wave pattern is shifted westward, and a dipole appears, having a wave crest in the western part of the cell, and a trough in the eastern part; after a half of the cycle the cell center is entered by a trough, and the west and east are occupied by wave crests; and in three quarters of the cycle the extremes being translated to the west will create in the mid-pool a dipole of opposite sign. Thus, the mixed picture of the positive and negative sea level anomalies as observed on altimetric maps can be explained by the nature of standing-progressive Rossby waves.