The Atlantic Meridional Overturning Circulation (AMOC) exhibits two stable states in models of varying complexity. Shifts between alternative AMOC states are thought to have played a role in past abrupt climate changes, but the proximity of the climate system to a threshold for future AMOC collapse is unknown. Generic early warning signals of critical slowing down before AMOC collapse have been...

We set up equations and boundary conditions for magnetic rotator winds and disks in axially symmetric hot stars in a steady state. We establish a theorem stating that if a disk region has no meridional motion but its magnetic field has a normal component at a point Q on its shock boundary, the angular velocity of the disk region at Q is the same as the angular velocity of the star at the point ...

This paper investigates the dynamical processes throughwhich the Tibetan Plateau (TP) influences theEast Asian summer monsoon (EASM) within the framework of the moist static energy (MSE) budget, using both observations and atmospheric general circulation model (AGCM) simulations. The focus is on the most prominent feature of the EASM, the so-called meiyu–baiu (MB), which is characterized by a w...

While stirring and mixing properties in the stratosphere are reasonably well understood in the context of balanced (slow) dynamics, as is evidenced in numerous studies of chaotic advection, the strongly enhanced presence of high-frequency gravity waves in the mesosphere gives rise to a significant unbalanced (fast) component to the flow. The present investigation analyses result from two ideali...

The evolution of the angular velocity profile in 10 and 30M main-sequence (MS) stars has been calculated from the initial uniform rotation to the asymptotic steady-state rotation. Following Zahn (1992) we assume that both transport of angular momentum and mixing of chemical elements are produced by rotationally induced meridional circulation and turbulent diffusion. It is shown that for a suffi...

The ability of paleoceanographic tracers to constrain rates of transport is examined using an inverse method to combine idealized observations with a geostrophic model. Considered are the spatial distribution, accuracy, and types of tracers required to constrain changes in meridional transport within an idealized single-hemisphere basin. Measurements of density and radioactive tracers each act ...

The Reynolds stress induced by anisotropically forcing an unbounded Couette flow, with uniform shear γ, on a β-plane, is calculated in conjunction with the eddy diffusivity of a co-evolving passive tracer. The flow is damped by linear drag on a time scale μ. The stochastic forcing is white-noise in time and its spatial anisotropy is controlled by a parameter α, that characterizes whether eddies...

Meridional diurnal tidal winds derived as described by Khattatov et al. [this issue] from the high-resolution Doppler imager (HRDI) data are used in the linearized tidal equations to solve for the diurnal tidal oscillations in the zonal and vertical velocity, pressure, temperature, and dissipation in the mesosphere and lower thermosphere. The resulting monthly mean latitude-altitude cross secti...

Observations of internal wave velocity fluctuations show that enhanced turbulent mixing over rough topography in the Southern Ocean is remarkably intense and widespread. Mixing rates exceeding background values by a factor of 10 to 1000 are common above complex bathymetry over a distance of 2000 to 3000 kilometers at depths greater than 500 to 1000 meters. This suggests that turbulent mixing in...