Talk:Trade winds/GA1

GA Review

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Reviewer: Pyrotec (talk) 09:51, 7 January 2010 (UTC)

Starting review. Pyrotec (talk) 09:51, 7 January 2010 (UTC)

Initial comments

I'm sorry that it has taken longer than I would have liked to get to this point. I read through this short article a few times and found it quite difficult to read; I've therefore spent a bit of time trying to improve the readability (a horrible word) (and I've been working on other things). I think some of the problems are due to the use of technical terms that are not introduced; and the inconsistent use of terms.

This article will possibly make it through GA if the prose is cleaned up. Its well reference referenced and it has some pretty pictures.

Going through the article section by section, but leaving the WP:Lead until last:

• History -

• Y Pyrotec (talk) 15:26, 10 January 2010 (UTC) - The claims in the first sentence aught to be referenced.

• I referenced the origin of the word trade. Thegreatdr (talk) 13:50, 10 January 2010 (UTC)

• Cause -

• Y Pyrotec (talk) 15:26, 10 January 2010 (UTC) - This section could do with a clean up on the prose.
• Y Pyrotec (talk) 16:43, 10 January 2010 (UTC) - Why use the term "poleward", which happens to be a link to Geographical pole? The clause "...towards the poles" would be better.

• Done. Thegreatdr (talk) 13:20, 10 January 2010 (UTC)

• Y Pyrotec (talk) 23:01, 11 January 2010 (UTC) - Some of the "difficulty" with the first paragraph seems to be the inconsistent use of "labels". The first sentence describes "surface air" and aloft (air), but in the rest of the section "superior air" is used (which I assume is the same).

• The concept of superior air is explained within the previous two lines before its first use. Superior air is air which originated above the Earth's surface, then descended which dries out/warms up air masses (also known as as adiabatic warming or expansion which I figured was too technical to introduce here). Can you think of a better way to describe it? I thought I used an appropriate transition which the sentence which first uses it states "This superior air mass..." Thegreatdr (talk) 13:29, 10 January 2010 (UTC)

• I understand adiabatic heating/cooling (also isothermal and isoperibol calorimetry); but not "weather systems". It strikes me that something is missing in the explanation. The article discusses surface flow and aloft/superior flow which descends at 30° (in both hemispheres). That to me is an unsustainable system. You can't just have descending air: the either superior air is going to run out or the surface air is going to get so dense it will prevent the superior air from sinking. If the system is going to keep running the air must rise somewhere to balance the descending air. Having searched all the wiklinks, that seems to be the Hadley cell, but its not obvious from the article that there is a cycle in the vertical plane as well as the equatorial-polar system that is described.
• Y Pyrotec (talk) 22:28, 11 January 2010 (UTC) - Sorry, the article does not mention heat exchange. If its part of the system, it aught to appear in an article aiming for GA standard. Pyrotec (talk) 16:43, 10 January 2010 (UTC)

• Trade winds don't involve cooling/heating at the surface. Superior air doesn't lose any absolute humidity, even if the relative humidity might change during its descent. Even though air mass cools off during ascent from the ITCZ and heat up due to descent near 30 latitude, no heat is added to the system. It's merely adiabatic cooling due to expansion above the ITCZ and adiabatic compression/heating near 30 latitude. Thegreatdr (talk) 22:09, 11 January 2010 (UTC)

• Y Pyrotec (talk) 22:41, 11 January 2010 (UTC) - I'm not sure what the middle bit of the following sentence is talking about: "This superior air mass is dry and subsident, or sinking through the troposphere, originating within the subtropical ridge, and rarely reaches the ground."
• Y Pyrotec (talk) 15:26, 10 January 2010 (UTC) - Sticking troposphere in the middle of this sentence is "strange", its the only appearance of this word. Should it not be introduced properly?

• I have tried to deal with the previous two items by introducing troposphere into the lead. Now, it is doubly covered with a wikilink and a short phrase describing which portion of the atmosphere the troposphere is. Thegreatdr (talk) 13:25, 10 January 2010 (UTC)

• Let's analyse: "Around 30° in both hemispheres air begins to descend toward the surface in subtropical high-pressure belts. The sinking air is relatively dry because its moisture has already been released near the equator. This superior air mass is dry and subsident, or sinking through the troposphere, originating within the subtropical ridge, and sometimes reaches the ground. The superior air normally resides over the top of maritime tropical air masses, forming a warmer and drier layer over the more moderate moist air mass below. The superior air mass normally forms a trade wind inversion over the maritime tropical air mass, which means warmer air aloft overlies a relatively cooler air mass at the surface.[12]" - It descends at 30°. Its dry because its rained at the equator. Its dry and its sinking (sinking means subsident). Something (it) unexplained originates within the subtropical ridge. Presumably, the sinking air sometimes reaches the ground. Inversion appears to be warmer drier air over moderate moisture air? Pyrotec (talk) 16:43, 10 January 2010 (UTC)

• The zone of upward motion/low pressure within the ITCZ/monsoon trough is the upward portion of the Hadley cell. The downward portion of the Hadley cell is composed of the subtropical ridges in both hemispheres around 30 latitude which are caused by the sinking/subsidence. Even if the ITCZ is rain free (which is it on occasion), the downward motion section of the Hadley cell would dry out the air mass at 30 latitude in both hemispheres. When the dry air from the subtropical ridge manages to reach the surface (which is more likely to occur over land due to stronger vertical motions over land), it is known as superior air. Even if superior air mixed down to the surface over tropical oceans, the warmth/moisture at the ocean surface would mix within the bottom 5000 feet/eighth of the atmosphere pressure-wise, which would cause that layer to moisten, and led to a temperature inversion above 5000 feet. A temperature inversion is an atmospheric layer where temperature increases with height, rather than decreases with height (which is the norm). In this case, the air above the mixed layer (the top of the trade wind inversion) is drier. Superior air masses near 30 latitude in both hemispheres contributes to the formation of deserts, particularly on the western side of continents such as Mexico/the southwest US, western South America, and Australia. Coastal mountains parallel to the shore help in desert creation when the westerlies descend the lee side of north/south mountain ranges. Europe is different in this regard because it does not have a cold water current offshore nor a coastal mountain range. One has to get east of the Urals to get into desert territory in western Asia/far eastern Europe. Thegreatdr (talk) 20:14, 10 January 2010 (UTC)

• I think that you have some stray text. I'm not sure what "south of the subtropical ridge." is doing in the middle paragraph after Coriolis effect. Pyrotec (talk) 22:33, 11 January 2010 (UTC)

• Weather effects -

• Y Pyrotec (talk) 15:30, 10 January 2010 (UTC) - Poleward !!!!!!

• Dealt with Thegreatdr (talk) 13:20, 10 January 2010 (UTC)

• Y Pyrotec (talk) 22:28, 11 January 2010 (UTC) - deep tropics - jargon - what are they & where are they?

• I just removed the word deep since it was creating unnecessary confusion. It was an unneeded adjective. Thegreatdr (talk) 13:32, 10 January 2010 (UTC)

• Y Pyrotec (talk) 15:32, 10 January 2010 (UTC) - This sentence could do with a clean up: "When dust from the Sahara moving around the southern periphery of the ridge moves over land, rainfall is suppressed and the sky changes from a blue to a white appearance which leads to an increase in red sunsets". (I don't like move and moving - one of these aught to be changed to a synonym).

• This has been done. Thegreatdr (talk) 13:35, 10 January 2010 (UTC)

• Y Pyrotec (talk) 23:01, 11 January 2010 (UTC) - Inversion appears once in every section except History, but its never been explained.

• I've taken a stab at its explanation. See if it's clear enough for you. Thegreatdr (talk) 13:41, 10 January 2010 (UTC)

• See my comments above. So if Inversion appears to be warmer drier air over moderate moisture air, the "Clouds which form within trade wind regimes are typically composed of shallow cumulus.....and are capped from being taller by the trade wind inversion", are in the "surface layer" and the surface is "no more than 4 kilometres (13,000 ft) in height"? Pyrotec (talk) 16:43, 10 January 2010 (UTC)

• The surface is the Earth's surface, simply put. The clouds are in the lower levels of the troposphere. Thegreatdr (talk) 23:17, 10 January 2010 (UTC)

• Y Pyrotec (talk) 15:30, 10 January 2010 (UTC) - There is pretty picture entitled "General distribution of air masses near North America". Is this merely decorative or does it serve some useful purpose? If it has a use, then mP, mT and cP aught to be explained. There is no explanation of the source image, but that does not excuse the lack of explanation in this article. Pyrotec (talk) 23:30, 9 January 2010 (UTC)

• I have explained its presence, as an mT air mass is the air mass within the trade wind regime.Thegreatdr (talk) 13:41, 10 January 2010 (UTC)

• All of the comments above have now been responded to. If they have been resolved to your satisfaction, strike them out so I know they are no longer issues. Thegreatdr (talk) 13:50, 10 January 2010 (UTC)

• Thanks for addressing my comments promptly. I happy to tick of many of the "actions", but not all of them. I'm also leaving the WP:lead until the end, but its possibly OK. In summary, at this stage I've still got unanswered questions in the article (even if the questions have not been asked). Pyrotec (talk) 16:43, 10 January 2010 (UTC)

• A rather "trival point" we refer in Weather effects to "shallow cumulus, which extend no more than 4 kilometres". That I assume is a ceiling of 4 kilometers for shallow clouds; do we have cumulus clouds with depths of several kilometers from top of bottom?

There are two minor points to resolve and I'm happy with the WP:Lead. We would be able to wrap this review up quite soon. Pyrotec (talk) 23:01, 11 January 2010 (UTC)

Okay. I think I've addressed the last two comments. Let me know if I haven't, or if you see anything else. Thegreatdr (talk) 22:06, 12 January 2010 (UTC)

You have misunderstood one of my comments. I was refering to this one, in red, not the text that you removed:

"The surface air that flows from these subtropical high-pressure belts toward the Equator is deflected toward the west in both hemispheres by the Coriolis effect.[13] south of the subtropical ridge. These winds blow predominantly from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere.[14] Because winds are named for the direction from which the wind is blowing,[15] these winds are called the northeast trade winds in the Northern Hemisphere and the southeast trade winds in the Southern Hemisphere. The trade winds meet at the doldrums.[8]" Pyrotec (talk) 22:32, 12 January 2010 (UTC)

Ok. It should be corrected now. Thegreatdr (talk) 01:36, 13 January 2010 (UTC)

Overall summary

GA review – see WP:WIAGA for criteria

1. Is it reasonably well written?

   A. Prose quality:

   B. MoS compliance:

2. Is it factually accurate and verifiable?

   A. References to sources:

   B. Citation of reliable sources where necessary:

   C. No original research:

3. Is it broad in its coverage?

   A. Major aspects:

   B. Focused:

4. Is it neutral?

   Fair representation without bias:

5. Is it stable?

   No edit wars, etc:

6. Does it contain images to illustrate the topic?

   A. Images are copyright tagged, and non-free images have fair use rationales:

   B. Images are provided where possible and appropriate, with suitable captions:

7. Overall:

   Pass or Fail:

The article is much improved; and I can now understand it. I'm awarding GA-status. Congratulations on this achievement. Pyrotec (talk) 10:23, 13 January 2010 (UTC)