Studies on the Mean Zonal Flow I

Zonal flow formation in the presence of ambient mean shear

the effects of changing roughness on the flow structure in the bends

flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...

Climatology and trends in the forcing of the stratospheric zonal-mean flow

The momentum budget of the Transformed Eulerian-Mean (TEM) equation is calculated using the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA-40) and the National Centers for Environmental Prediction (NCEP) Reanalysis 2 (R-2). This study outlines the considerable contribution of unresolved waves, deduced to be gravity waves, to the forcing of the zonal-mean flow. A tren...

Multiple regimes and low-frequency oscillations in the Northern Hemisphere’s zonal-mean flow

This paper studies multiple regimes and low-frequency oscillations in the Northern Hemisphere zonal-mean zonal flow in winter, using 55 years of daily observational data. The probability density function estimated in the phase space spanned by the two leading empirical orthogonal functions exhibits two distinct, statistically significant maxima. The two regimes associated with these maxima desc...

Bimodal Behavior in the Zonal Mean Flow of a Baroclinic β-Channel Model

The dynamical origin of midlatitude zonal-jet variability is examined in a thermally forced, quasi-geostrophic, two-layer channel model on a β-plane. The model’s behavior is studied as a function of the bottom-friction strength. Two distinct zonal-flow states exist at realistic, low and intermediate values of the bottom drag; these two states are maintained by the eddies and differ mainly in te...