The Mean-Meridional Transport Circulation of the Troposphere in an Idealized GCM
- 1 May 2002
- journal article
- Published by American Meteorological Society in Journal of the Atmospheric Sciences
- Vol. 59 (9), 1502-1514
- https://doi.org/10.1175/1520-0469(2002)059<1502:tmmtco>2.0.co;2
Abstract
Large numbers of particle trajectories are used to characterize the mean-meridional transport circulation of an idealized general circulation model (GCM). The GCM has a uniform land surface, no topography or land–sea contrasts, and no seasonal cycle. The trajectories are analyzed using both Lagrangian-mean statistics and an approach based on the Green's function of the tracer transport equation. It is shown that the distribution of particle trajectories provides an estimate of the ensemble-mean Green's function for the inviscid transport equation. Lagrangian means have a number of problems that render their interpretation difficult, including boundary effects and selection of the appropriate averaging period. The Green's function, on the other hand, provides a quantitative description of the transport circulation that is easy to visualize and interpret. The results demonstrate that within the idealized model the atmosphere can be divided into three parts: the Southern Hemisphere extratropics, the Tropics, and the Northern Hemisphere extratropics. Climatologically, particle dispersion within each part of the atmosphere is rapid, while exchange between the different parts is much slower. There is a semipermeable transport barrier between the Tropics and extratropics. The interhemispheric exchange rate in the model is toward the slower end of estimates from observations, possibly due to the higher degree of zonal symmetry in the model.Keywords
This publication has 29 references indexed in Scilit:
- Interhemispheric Exchange by Seasonal Modulation of the Hadley CirculationJournal of the Atmospheric Sciences, 1997
- Rossby Wave Phase Speeds and Mixing Barriers in the Stratosphere. Part I: ObservationsJournal of the Atmospheric Sciences, 1996
- The permeability of the Antarctic vortex edgeJournal of Geophysical Research: Atmospheres, 1994
- Large‐scale isentropic mixing properties of the Antarctic polar vortex from analyzed windsJournal of Geophysical Research: Solid Earth, 1993
- The calculation of stratospheric air parcel trajectories using satellite dataQuarterly Journal of the Royal Meteorological Society, 1985
- A Finite-Amplitude Eliassen-Palm Theorem in Isentropic CoordinatesJournal of the Atmospheric Sciences, 1983
- An exact theory of nonlinear waves on a Lagrangian-mean flowJournal of Fluid Mechanics, 1978
- Energy Spectra Predicted by Semi-Geostrophic Theories of FrontogenesisJournal of the Atmospheric Sciences, 1978
- The Noninteraction of Waves with the Zonally Averaged Flow on a Spherical Earth and the Interrelationships on Eddy Fluxes of Energy, Heat and MomentumJournal of the Atmospheric Sciences, 1976
- Planetary Waves in Horizontal and Vertical Shear: The Generalized Eliassen-Palm Relation and the Mean Zonal AccelerationJournal of the Atmospheric Sciences, 1976