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Article Evaluation

Evaluating Content- While everything in the article is relevant to the topic, there is only one paragraph, one visual, and only two citations in this entry. The article is missing information about the current status of the Brewer-Dobson circulation theory and is missing support from evidence. The information is also out of date, using citations from 1990 and 2001 when more current research exists on the subject of Brewer-Dobson circulation. However, the article does not use any other Wikipedia pages as reference, and all of the information is clear and accurate, just simply outdated. The information needs to be elaborated on to include examples of Brewer-Dobson circulation (such as in the tropics and extratropical latitudes), evidence as to why the theory of Brewer-Dobson circulation even exists (hemispheric differences in water transport and planetary wave activity, radiative balance, sinking air and meridionial overturning, etc.), changes in Brewer-Dobson circulation in the last four decades (using most recent research), and recent challenges in understanding the circulation theory and its response to climate change. Supporting citations based on research from 2014 and 2019 and supporting visuals can be added to enhance readers' understating of the information.

Evaluating Tone- The article is very neutral and simply states facts about when the theory of Brewer-Dobson circulation came about and an extremely concise summary about what it argues. The information simply focuses on providing a summary and does not lean towards arguing any perspectives or claims about the theory.

Evaluating Sources- The sources used are very credible, all of the citations are accurate, and the links to the citations and sources work. While the sources are outdated, they are still peer-reviewed, scholarly sources.

Evaluating Talk Page- In the Talk page, this article was deemed to be a part of the WikiProject Meteorology, which aims to improve the coverage of Meteorology on Wikipedia. However, this project specifically was rated as a Stub-Class on the project's quality scale and was rated as Low-Importance on the project's importance scale.

Adding to the Talk Page (Feedback)- While everything in the article is relevant to the topic, there is only one paragraph, one visual, and only two citations in this entry. The article is missing information about the current status of the Brewer-Dobson circulation theory and is missing support from evidence. The information is also out of date, using citations from 1990 and 2001 when more current research exists on the subject of Brewer-Dobson circulation. However, the article does not use any other Wikipedia pages as reference, and all of the information is clear and accurate, just simply outdated. The information needs to be elaborated on to include examples of Brewer-Dobson circulation (such as in the tropics and extratropical latitudes), evidence as to why the theory of Brewer-Dobson circulation even exists (hemispheric differences in water transport and planetary wave activity, radiative balance, sinking air and meridionial overturning, etc.), changes in Brewer-Dobson circulation in the last four decades (using most recent research), and recent challenges in understanding the circulation theory and its response to climate change. Supporting citations based on research from 2014 and 2019 and supporting visuals can be added to enhance readers' understating of the information. The sources used currently are very credible and are peer-reviewed and scholarly, but they are outdated.

Article Draft
Brewer–Dobson circulation is a model of atmospheric circulation, proposed by Alan Brewer in 1949 and Gordon Dobson in 1956, which attempts to explain why tropical air has less ozone than polar air, even though the tropical stratosphere is where most atmospheric ozone is produced. It is a simple circulation model that posits the existence of a slow current in the winter hemisphere which redistributes air from the tropics to the extratropics. The Brewer–Dobson circulation is driven by atmospheric waves and may be speeding up due to climate change.

Models
Since the Brewer-Dobson circulation does not have an explicit definition, it has been used loosely to describe a general range of overturning circulations. The original model describing the circulation was produced by Gordon Dobson (1929) and Alan Brewer (1949), with a corresponding model formed by Timothy Dunkerton in 1978.

Mass and Diabatic Circulation
The averaged mass circulation of the stratosphere is explained by the transport of conservative tracers such as ozone. Tracers generally have weak sources and decay rates. The Brewer-Dobson circulation has a direct impact on the distribution and abundance of stratospheric ozone by moving it throughout the tropics and polar regions. The ozone hole has been closing since 2000, which was preceded by a period of ozone depletion. Changes in the ozone affect the annual mean of the Brewer-Dobson circulation, which is seen in the fact that the annual mean has accelerated for the past forty years, leading to a cooling of the tropical lower stratosphere and warming in high latitudes. Mass circulation is also approximated by the averaged diabatic circulation, following the original approach of F. Singleton and R. J. Murgatroyd in 1961.

Transformed Eulerian Mean Circulation
The disparity between the Eulerian-mean circulations and the diabatic circulations can be traced to a nonlinear rectification of eddy transport contributing to the mean transport. The residual-mean circulation (v*,w*) is outlined by two thermodynamic equation s. The residual-mean circulation satisfies the mass-continuity equation related to the corresponding transformation of the thermodynamic equation.

Generalized Lagrangian-Mean and Transport Circulations
The generalized Lagrangian-mean circulation can be estimated by the diabatic and residual-mean circulations, as argued by Timothy Dunkerton (1978). This model demonstrates the mean over sets of moving fluid parcels instead of the mean of latitudes as an alternative. One of the faults of the Lagrangian-mean circulation model is its inability to satisfy the mass-continuity equation and its large divergent factor differing from the mean flow, which was overcome in 1987 by R. Alan Plumb and Jerry D. Mahlman, who defined transport-circulation as representative of advective transport by the non-divergent component and produced as a new transport-circulation representing Lagrangian-mean velocities.

Mixing and Transport Barriers
Two-way mixing, based on the processes researched in 1987, is essential to stratospheric transport. This stratospheric transport can be represented by vertical advection combined with two-way mixing. Potential velocity gradients created by mixing within the surf-zone creates barriers to transport, occurring around the winter polar vertex, in the summer hemisphere, and in other regions. There are four main regions created by this mixing: the winter polar vertex, the summer hemisphere, the Tropics, and the surf-zone.

Mean Age of Air
The mean age-of-air model combines the diabatic circulation and residual-mean circulations with two-way mixing and stirring of air parcels. It demonstrates how, due to mixing, an air parcel can be composed of air from many different transport pathways with various transit times rather than traveling to one location from an initial one. The Brewer-Dobson circulation model establishes a mean age of air by transporting air in and out of the stratosphere. As researched by H. Kida in 1938, a parcel does not simply have an age; it contains a spectrum of ages and an associated estimated average age.