Left-hand Rule for Synoptic Eddy Feedback on Low-frequency Flow
국종성; F.-F. Jin; 박주현; H.-L. Ren
This left-hand rule of eddy-vorticity fluxes relative to low-frequency flow indicates positive feedback of synoptic eddy forcing on the low-frequency flow. If the low-frequency flow is cyclonic (anticyclonic), the eddy vorticity fluxeswill converge (diverge) to the center of the cyclonic (anticyclonic) flow based on the left-hand rule, indicating that the vorticity fields of low-frequency flow are reinforced. This relation confirms the results of the pioneer work by Lau . Note that the eddy feedback will be maximized when the eddy vorticity flux is perpendicular to the left-hand side of low-frequency flow. Therefore, this positive feedback plays an important role in the dominance of climatic modes, such NAO (North Atlantic Oscillation) and PNA (Pacific -North America) patterns.