Experiments With a Stratospheric General Circulation Model

Manabe, Syukuro; Hunt, B. G.

doi:10.1175/1520-0493(1968)096<0477:ewasgc>2.0.co;2

Cited by 76 publications

(38 citation statements)

References 26 publications

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“…The statistics of temperature and motions as a whole well agree with those of the actual atmosphere. But, as being so in this kind of models (e.g., Manabe and Hunt, 1968), the zonal means of temperature and motion resemble those observed in winter rather than those of annual mean and the activity of eddies is somewhat weaker than that in winter.…”

Section: Time Integrationmentioning

confidence: 65%

General Circulation of Air Parcels and Transport Characteristics Derived from a hemispheric GCM

Kida¹

1983

Journal of the Meteorological Society of Japan

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An advective motion in the lower stratosphere is determined calculating trajectories of a large number of air parcels in a quasi-equilibrium general circulation obtained from a long-term integration of a GCM over the hemispheric domain . A new method is developed for deducing the advective motion of air parcels, i.e., the non-divergent part of the Lagrangianmean motion; the method is to calculate the usual Lagrangian-mean motion of air parcels both forward and backward in time, and then to take the average of the two .It is clearly shown that the advective motions of air mass in the lower stratosphere form one cell with an upward branch at the tropics and a downward branch in high latitudes , being quite different from the usual zonal-mean meridional circulations having direct and indirect cells over the tropical and extratropical regions, respectively.The regions of the upward and downward motions coincide very well with those of the radiative heating and cooling, respectively. This suggests a balance between the adiabatic heating/cooling due to the vertical motion of air parcels and the diabatic heating/cooling.From the dispersion rate of a large number of air parcels initially located along a latitude circle at the same interval of longitude, eddy diffusion coefficients are estimated as *3*109cm2/s in the horizontal and *l*103cm2/s in the vertical. These values are one order or more smaller than those employed in most of 2-D transport models . The results seem to be reasonable in recent theories of Lagrangian dynamics of planetary waves . However, note that the horizontal diffusion as well as the horizontal advection plays an important role in poleward movements of air parcels in the lower stratosphere .Furthermore, a new formulation of a 2-D transport model based on the advective motion and diffusion of air parcels is briefly discussed.

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Section: Time Integrationmentioning

confidence: 65%

General Circulation of Air Parcels and Transport Characteristics Derived from a hemispheric GCM

Kida¹

1983

Journal of the Meteorological Society of Japan

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“…The lack of any transports of angular momentum by the meridional cells is a feature of a quasigeostrophic model that was particularly evident in the angular momentum budget. Manabe and Hunt (1968) found the general features of the lower stratosphere to be much better simulated with a high resolution model.…”

Section: Source Of Discrepanciesmentioning

confidence: 91%

Dynamic Coupling of the Stratosphere With the Troposphere and Sudden Stratospheric Warmings

Trenberth¹

1973

Mon. Wea. Rev.

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Numerical time integrations of a 9-layer quasigeostrophic highly truncated spectral model of the atmosphere are used to study tropospheric-stratospheric interaction with particular regard to sudden stratospheric warmings. The model is global and extends to 0.05 mb (71 km) with roughly 10 km resolution in the stratosphere, and includes an annual heating cycle. A linear baroclinic analysis of a similar model shows that the inclusion of spherical geometry allows significant growth rates in the long wave region of instability. Preliminary integrations without eddies reveal the seasonal variation of a thermally driven circulation.Model integrations simulating the months of December and January were made (i) without nonzonal forcing, and (ii) with nonzonal heating and orography included, to represent southern and northern hemisphere winters. The overall features of the atmosphere were very well simulated. With the inclusion of the annual heating cycle, the model successfully reproduced a more intense circulation in January than existed in December. This caused a maximum tropospheric meridional temperature gradient in the winter hemisphere to occur some weeks prior to the maximum in the external heating field.The presence of nonzonal heating in the winter hemisphere brought about an increase in circulation intensity and produced a stationary perturbation with a strong westward slope with height extending high into the stratosphere.These are features somewhat similar to those of the Aleutian system. Associated with this were considerably warmer temperatures in the polar night stratosphere and a weaker stratospheric westerly jet.The winter mesosphere of the model was driven in the manner of the lower stratosphere and a temperature maximum was produced in mid latitudes.Sudden stratospheric warmings occurred as a result of large , increases in the intensity of planetary scale waves in the troposphere, which in turn produced surges of upwards propagating energy. The energetics of the warming occurred in two phases. A change from a baroclinically direct to a driven circulation occurred as the stratospheric temperature gradient reversed. This coincided with a change from enhancement to absorption of the vertical flux of energy. The mechanism of the warming was much as described by Matsuno (1971).Nonlinear interactions between the progressive long wave and the nonzonal heating were primarily responsible for the tropospheric events that produced the upward flux of energy, which in turn caused the stratospheric warmings. A seasonal index cycle in the very long waves was also of significance in producing transient upward energy propagation. Interactions with other waves, and orographic forcing were of secondary importance in the long wave energetics of the sudden warmings.

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“…A deep stratosphere wind braking description with p low = 0.1 bar and k max = 1/20 days −1 furthermore reproduces the observed wind speeds (Figure 3,upper panel). See, e.g., Manabe & Hunt (1968) or the review by Haynes (2005) for comparison with the observed Earth zonal wind structure.…”

Section: Earth Benchmarking and Eddy Diagnosticsmentioning

confidence: 99%

Stratosphere circulation on tidally locked ExoEarths

Carone

Keppens

Decin

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Stratosphere circulation is important to interpret abundances of photo-chemically produced compounds like ozone that we aim to observe to assess habitability of exoplanets. We thus investigate a tidally locked ExoEarth scenario for TRAPPIST-1b, TRAPPIST-1d, Proxima Centauri b and GJ 667 C f with a simplified 3D atmosphere model and for different stratospheric wind breaking assumptions.These planets are representatives for different circulation regimes for orbital periods: P or b = 1 − 100 days. The circulation of exoplanets with P or b 25 days can be dominated by the standing tropical Rossby wave in the troposphere and also in the stratosphere: It leads to a strong equatorial eastward wind jet and to 'Anti-Brewer-Dobson'-circulation that confines air masses to the stratospheric equatorial region. Thus, the distribution of photo-chemically produced species and aerosols may be limited to an 'equatorial transport belt'. In contrast, planets with P or b > 25 days, like GJ 667 C f, exhibit efficient thermally driven circulation in the stratosphere that allows for a day side-wide distribution of air masses.The influence of the standing tropical Rossby waves on tidally locked ExoEarths with P or b 25 days can, however, be circumvented with deep stratospheric wind breaking aloneallowing for equator-to-pole transport like on Earth. For planets with 3 P or b 6 days, the extratropical Rossby wave acts as an additional safe-guard against the tropical Rossby wave in case of shallow wind breaking. Therefore, TRAPPIST-1d is less prone to have an equatorial transport belt in the stratosphere than Proxima Centauri b. Even our Earth model shows an equatorial wind jet, if stratosphere wind breaking is inefficient.

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Experiments With a Stratospheric General Circulation Model

Cited by 76 publications

References 26 publications

General Circulation of Air Parcels and Transport Characteristics Derived from a hemispheric GCM

General Circulation of Air Parcels and Transport Characteristics Derived from a hemispheric GCM

Dynamic Coupling of the Stratosphere With the Troposphere and Sudden Stratospheric Warmings

Stratosphere circulation on tidally locked ExoEarths

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