A locally applicable (nonzonally-averaged) conservation relation is derived for quasi-geostrophic stationary waves on a zonal flow, generalization of the Eliassen-Palm relation. The flux which appears in this constitutes, it argued, useful diagnostic three-dimensional propagation wave activity. This illustrated by application to simple theoretical model forced Rossby train and Northern Hemisphere winter climatology. Results latter procedure suggest that major forcing field derives from...

Estimates of stratospheric age from observations long‐lived trace gases with increasing tropospheric concentrations invoke the implicit assumption that an air parcel has been transported intact tropopical tropopause. However, because rapid and irreversible mixing in stratosphere, a particular cannot be identified one left troposphere at some prior time. The contains mix range transit times, mean value over this is most appropriate definition age. measured tracer concentration also parcel,...

Recent analyses have revealed simple relationships between the simultaneously measured mixing ratios of certain stratospheric constituents. In some cases, relationship appears to be nearly linear, so that concentrations one can used predict other. We argue here such are expected for species sufficiently long lifetime. Species whose local lifetimes longer than quasi‐horizontal transport time scales in climatological slope equilibrium, i.e., they share surfaces constant ratio, and a scatter...

Improvements in our understanding of transport processes the stratosphere have progressed hand with advances stratospheric dynamics and accumulating remote situ observations distributions of, relationships between, tracers. It is convenient to regard as being separated into four regions: summer hemisphere, tropics, wintertime midlatitude "surf zone", winter polar vortex. Stratospheric dominated by mean diabatic advection (upwelling downwelling surf zone vortex) and, especially, rapid...

Abstract An equatorial beta‐plane model of wave‐mean flow interaction in the lower stratosphere is described. Kelvin and mixed Rossby‐gravity waves generated by a specified forcing on boundary radiate upward through domain where they are subject to thermal mechanical dissipation. The feedback problem solved assumption that changes zonal mean state occur slowly enough for wave field be steady, locally time. A quasi‐biennial oscillation develops with period about 1000 days. novel feature this...

For advanced undergraduate and beginning graduate students in atmospheric, oceanic, climate science, Atmosphere, Ocean Climate Dynamics is an introductory textbook on the circulations of atmosphere ocean their interaction, with emphasis global scales. It will give a good grasp what oceans look like large-scale why they that way. The role paleoclimate also discussed. combination observations, theory accompanying illustrative laboratory experiments sets this text apart by making it accessible...

A conceptual model of global stratospheric transport is described, based on the assumption rapid isentropic mixing within midlatitude “surf zones” but weak into tropics. Thus tropical region isolated from middle latitudes, and trace species budgets there are balances between mean upwelling local chemical sources sinks. In where long‐lived assumed to be in “slope equilibrium,” more complex, being influenced by mixing, downwelling, entrainment tropics, chemistry. The one‐dimensional vertical...

The GFDL general circulation/tracer model has been used to generate the transport coefficients required in two-dimensional (zonally averaged) formulations. This was done by assuming a flux-gradient relationship and then, given gradient flux statistics from two independent (and contrived) tracer experiments, derive inversion of this relation. Given mean meridional circulation GCM, antisymmetric symmetric parts tensor determine advective diffusive contributions net model. effective thus...

Internal waves propagating through a dissipative fluid interact with the mean flow. In response to forcing by single wave, flow evolves steady solution. presence of two (or more) such solution exists but is unstable. The underlying dynamics in latter case are basically those discussed Holton and Lindzen (1972) their theory quasi-biennial oscillation. If viscosity small nonzero zonal exhibits long-period This study elucidates dependence period structure oscillation on imposed parameters,...

We evaluate transport characteristics of two‐ and three‐dimensional chemical models the stratosphere by comparing their simulations mean age stratospheric air propagation annually periodic oscillations in tracer mixing ratio at tropical tropopause into to inferences from situ satellite observations CO 2 , SF 6 water vapor. The models, participants recent NASA “Models Measurements II” study, display a wide range performance. Most propagate annual too rapidly vertical overattenuate signal....

The fine‐scale structure in lower stratospheric tracer transport during the period of two Arctic Airborne Stratospheric Expeditions (January and February 1989; December 1991 to March 1992) is investigated using contour advection with surgery calculations. These calculations show that Rossby wave breaking an ongoing occurrence these periods air ejected from polar vortex form long filamentary structures. There good qualitative agreement between filaments measurements chemical tracers taken...

Observations of the “quasi-two-day” wave are reviewed and it is concluded that weight evidence indicates a solstical phenomenon, with maximum amplitudes in low latitudes summer mesosphere. It suggested properties this similar found numerical model middle atmosphere may be consistent an origin via baroclinic instability easterly jet This suggestion supported by results stability analysis one-dimensional mesospheric flow.

We present a trajectory technique, contour advection with surgery (CAS), for tracing the evolution of material contours in specified (including observed) evolving flow. CAS uses algorithms developed by Dritschel dynamics/surgery to trace contours. The are represented series particles, which advected specified, gridded, wind distribution. resolution is preserved continually adjusting number and finescale features produced that not input data (and cannot easily be generated using standard...

An experiment is described in which a standing internal wave forced at the lower boundary of an annulus salt-stratified water. At sufficiently large forcing amplitudes, motion generates strong mean azimuthal circulation itself exhibits long-period oscillation. Theoretical calculations, based on wave-driven theory quasi-biennial oscillation tropical stratosphere (with suitable modifications), are performed and compared with experimental results. Agreement good study thus provides substantial...

An approximate theory is developed of small-amplitude transient eddies on a slowly varying time-mean flow. Central to this flux MT, which in most respects constitutes generalization the Eliassen–Palm three dimensions; it conservable measure eddy activity (for small amplitude transients) and parallel group velocity for an almost-plane wave train. The use as diagnostic propagation demonstrated by application ten-year climatology Northern Hemisphere winter circulation. Results show anticipated...

General kinematical arguments are used to derive certain properties of eddy fluxes conserved quantities in a field small-amplitude waves. The direction the flux is related simple way wave transience and dissipation; absence local sources sinks steady directed normal background gradient. expressed as sum advective diffusive terms addition nondivergent contribution.

The recent discovery of large ionospheric disturbances associated with sudden stratospheric warmings (SSW) has challenged the current understanding mechanisms coupling stratosphere and ionosphere. Non‐linear interaction planetary waves tides been invoked as a primary mechanism for such coupling. Here we show that may play more complex role than previously thought. Planetary wave forcing induces global circulation leads to build‐up ozone density in tropics at 30–50 km altitude, region...

Investigations of the kinematics lower stratospheric Arctic vortex during winter 1991–1992 using contour advection with surgery technique reveal three distinct events in which there was substantial intrusion midlatitude air into vortex, apparent contradiction view that polar constitutes an isolated mass. Two these events, late January and mid‐February, were well documented. They predicted high‐resolution forecasts by European Centre for Medium‐Range Weather Forecasts, most clearly...

We discuss the characteristics of analytical solutions for mean age air in a simple, one‐dimensional conceptual model stratospheric transport. This “leaky pipe” is version “tropical which has been modified to include detrainment surf zone into tropics. examine dependence on advection, diffusive mixing, and quasi‐horizontal mixing between zones In absence vertical diffusion across tracer ratio isopleths difference tropics midlatitudes does not depend edge tropics, but only advection. The...

The occurrence of mixing polar vortex air with midlatitude is investigated by examining the scatterplots insitu measurements long‐lived tracers from NASA ER‐2 aircraft during Stratospheric Photochemistry, Aerosols and Dynamics Expedition (SPADE, April, May 1993; northern hemisphere) Airborne Southern Hemisphere Ozone Experiment / Measurements for Assessing Effects Aircraft (ASHOE/MAESA, March‐October 1994; southern campaigns. tracer‐tracer SPADE form correlation curves which differ those...

We consider the response of a zonally symmetric atmosphere to thermal forcing that is localized in subtropics. Specifically, equilibrium temperature distribution has local subtropical peak and flat elsewhere, including at equator. On basis inviscid steady-state theory, it argued such one two distinct types. Below threshold adopts steady state with no meridional flow. With supercritical forcing, this breaks down strong circulation predicted. The value which absolute vorticity zonal flow (in...

Recent advances in our understanding of the dynamics stratospheric circulation have led to concepts “downward control” and “extratropical pump.” However, under assumptions on which these are based, midlatitude wave driving cannot explain fact that mean upwelling is located Tropics. Nevertheless, using a nonlinear two-dimensional model it shown here steady (in lower stratosphere) linear with qualitatively reasonable can be produced, provided drag extends within about 20° equator. In analysis...

Abstract The applicability of axisymmetric theory angular momentum conserving circulations to the large-scale steady monsoon is studied in a general circulation model with idealized representations continental geometry and simple physics. Results from an aquaplanet setup localized subtropical forcing are compared case. It found that meridional develops close for cross-equatorial cells, both cases. equator proves be substantial barrier boundary layer flow; flow into summer hemisphere winter...

The properties and stability of forced planetary waves in a continuous baroclinc shear are investigated gated using weakly nonlinear analysis. A steady solution exists which under certain conditions may be unstable via interaction with free traveling wave the same wavenumber. This then grows at expense zonal mean available potential energy. parameter range instability occurs is extended by finite-amplitude perturbations. Theoretical predictions compared results from highly truncated model...