Left-hand rule for synoptic eddy feedback on low-frequency flow
نویسندگان
چکیده
[1] In this study, scale interaction between synoptic eddies and low-frequency flow is investigated. The synoptic eddy feedback is a key process in sustaining the low-frequency flow. We show clear evidence using NCEP reanalysis data that there is a general underlying rule—the ‘‘left-hand rule’’, governing the synoptic eddy feedback onto low-frequency flow. This rule states that eddy-vorticity fluxes are directed preferentially about 90 degrees toward their left-hand side, so that they converge into cyclonic flow and diverge from anticyclonic flow. Therefore, the eddy vorticity flux plays a positive role in reinforcing low-frequency flow. Citation: Kug, J.-S., and F.-F. Jin (2009), Left-hand rule for synoptic eddy feedback on low-frequency flow, Geophys. Res. Lett., 36, L05709, doi:10.1029/2008GL036435.
منابع مشابه
Scale interaction between tropical instability waves and low-frequency oceanic flows
[1] Tropical instability waves (TIWs), prevailing in the tropical Pacific and Atlantic Oceans, interact with the lowfrequency oceanic flow. It is known that TIWs act as negative feedback to ENSO through a thermal process. In this study, we examine the dynamical eddy feedback of TIWs. We show that in terms of physical processes, the dynamical TIW feedback is very similar to the atmospheric synop...
متن کاملTransformed eddy-PV flux and positive synoptic eddy feedback onto low-frequency flow
Interaction between synoptic eddy and lowfrequency flow (SELF) has been the subject of many studies. In this study, we further examine the interaction by introducing a transformed eddy-potential-vorticity (TEPV) flux that is obtained from eddy-potential-vorticity flux through a quasi-geostrophic potential-vorticity inversion. The main advantage of using the TEPV flux is that it combines the eff...
متن کاملInteractions between the tropical ISO and midlatitude low-frequency flow
In this study, we investigate the interaction between the tropical Intraseasonal Oscillation (ISO) and midlatitude atmospheric low-frequency variability, using observational data and numerical models, with a special emphasis on the role of the synoptic eddy feedback. A statistical closure for the synoptic eddy-to-low frequency flow feedback is constructed, based on a singular value decompositio...
متن کاملDynamics of Synoptic Eddy and Low-Frequency Flow Interaction. Part I: A Linear Closure
The interaction between synoptic eddy and low-frequency flow (SELF) has been recognized for decades to play an important role in the dynamics of the low-frequency variability of the atmospheric circulation. In this three-part study a linear framework with a stochastic basic flow capturing both the climatological mean flow and climatological measures of the synoptic eddy flow is proposed. Based ...
متن کاملEddy-Induced Instability for Low-Frequency Variability
Synoptic eddy–mean flow interaction has been recognized as one of the key sources for extratropical lowfrequency variability. In this paper, the underlying dynamics of this interaction are examined from the perspective of a synoptic eddy-induced dynamic instability. To delineate this instability, a barotropic model is used that is linearized with respect to a stochastic basic flow prescribed wi...
متن کامل