User:Chih-Lun Liu/Evaluate an Article

Evaluate an article
This is where you will complete your article evaluation. Please use the template below to evaluate your selected article.


 * Name of article: Saharan Air Layer
 * Briefly describe why you have chosen this article to evaluate.

The reason I have chosen to evaluate this article is that this topic is very intriguing to me. The dust layer can travel such a far distance and impact not only the local ecosystem but also the global climate. However, research on Saharan air layer are not well studied, the understanding is still developing. As a result, this topic on Wiki page is lack of reliable citations. So this article may be a good option to evaluate.

Lead
The Saharan Air Layer (SAL) is an extremely hot, dry and sometimes dust-laden layer of the atmosphere that often overlies the cooler, more-humid surface air of the Atlantic Ocean. It carries upwards of 60 million tonnes of dust annually over the ocean and the Americas. This annual phenomena sometimes cools the ocean and suppresses Atlantic hurricane creation.

The SAL is a subject of ongoing study and research. Its existence was first postulated in 1972.


 * Guiding questions:
 * Does the Lead include an introductory sentence that concisely and clearly describes the article's topic?
 * Does the Lead include a brief description of the article's major sections?
 * Does the Lead include information that is not present in the article?
 * Is the Lead concise or is it overly detailed?

Lead evaluation
Yes, the first sentence have done a good job on describing what the SAL is. It has no brief description of the major sections, namely, how the layer is created and its effects. The lead has mostly been covered in the article except the chronology (or when it was first postulated) that has not been mentioned in the article. Overall, the lead is quite concise.

Content

 * Guiding questions

Creation[edit]
The dust cloud originates in Saharan Africa and extends from the surface upwards several kilometers. As the dust drives, or is driven out over the Atlantic ocean, it is lifted above the denser marine air. This atmospheric arrangement is an inversion where the temperature actually increases with height, as the boundary between the SAL and the marine layer suppresses or "caps" any convection originating in the marine layer. Since it is dry air, the lapse rate within the SAL itself is steep, that is, the temperature falls rapidly with height.

Disturbances such as large thunderstorm complexes over North Africa periodically result in vast dust and sand storms, some of which extend as high as 6,000 metres (20,000 ft). The layer is transported westwards cross the Atlantic by a series of broad anticyclonic eddies that are typically found 1,500–4,500 metres (4,900–14,800 ft) above sea level. An estimated 60-200 million tons of dust particles are carried from the Sahara Desert region of North Africa, where it originates, and moves westward annually.

Researchers (Yücekutlu, N. et al., 2011) from Hacettepe University have reported that Saharan soil may have bio-available iron and also some essential macro and micro nutrient elements suitable for use as fertilizer for growing wheat. It has been shown that Saharan soil may have the potential of producing bioavailable iron when illuminated with visible light and also it has some essential macro and micro nutrient elements. Saharan soil sample was analyzed by XRD technique (x-ray diffraction technique) the dominant mineral was quartz, feldspar, calcite, gypsum and clay followed respectively.

Sometimes a depression to the southwest of the Canary Islands increases the wind speed and intensity of the SAL, which can lift the dust around 5,000 metres (16,000 ft) into the air and often carries the dust as far as the Caribbean.

Effects[edit]
The SAL passes over the Canary Islands where the phenomenon is named "Calima" (English: "Haze") and manifests as a fog that reduces visibility and deposits a layer of dust over everything. It is especially prevalent in the winter months. Canary islanders suffer respiratory problems during this weather event, and sometimes the dust is so bad, public life and transport halt completely. In fact, on January 8, 2002, the dust was so heavy over the Tenerife South Airport, dropping the visibility to 50 metres (160 ft), it was forced to close.

From Northern Africa, winds blow twenty percent of dust from a Saharan storm out over the Atlantic Ocean, and twenty percent of that, or four percent of a single storm's dust, reaches all the way to the western Atlantic. The remainder settles out into the ocean or washes out of the air with rainfall.[citation needed] Scientists believe the July 2000 measurements made in Puerto Rico, nearly 8 million tonnes, equaled about one-fifth of the year's total dust deposits.[citation needed]

The clouds of dust SAL creates are visible in satellite photos as a milky white to gray shade, similar to haze.[citation needed]

Findings to date indicate that the iron-rich dust particles that often occur within the SAL reflect solar radiation, thus cooling the atmosphere. The particles also reduce the amount of sunlight reaching the ocean, thus reducing the amount of heating of the ocean. They also tend to increase condensation as they drift into the marine layer below, but not precipitation as the drops formed are too small to fall and tend not to readily coalesce.[jargon] These tiny drops are subsequently more easily evaporated as they move into drier air laterally or dry air mixes down from the SAL aloft. Research on aerosols also shows that the presence of small particles in air tends to suppress winds. The SAL has also been observed to suppress the development and intensifying of tropical cyclones, which may be related directly to these factors.


 * Is the article's content relevant to the topic?
 * Is the content up-to-date?
 * Is there content that is missing or content that does not belong?
 * Does the article deal with one of Wikipedia's equity gaps? Does it address topics related to historically underrepresented populations or topics?

Content evaluation
The article's content is well relevant, however, the citations are not up-to-date in which they are mostly before 2015 and some are in the early 2000.

They should mention the influence of SAL on Amazon rainforest and how SAL can damp the hurricane or tropical cyclones on full detail.

No, the article neither deals with equity gaps nor related historically underrepresented populations or topics.

Tone and Balance

 * Guiding questions


 * Is the article neutral?
 * Are there any claims that appear heavily biased toward a particular position?
 * Are there viewpoints that are overrepresented, or underrepresented?
 * Does the article attempt to persuade the reader in favor of one position or away from another?

Tone and balance evaluation
Yes, the article is neutral, and most of the informations are based on facts, there are no bias,

Sources and References

 * Guiding questions

References[edit]

 * 1) ^ Jump up to:a b
 * 2) ^ Jump up to:a b
 * 3) ^
 * 4) ^
 * 5) ^
 * 6) ^ Yücekutlu, Nihal; Terzioğlu, Serpil; Saydam, Cemal; Bildacı, Işık (2011)."Organic Farming By Using Saharan Soil: Could It Be An Alternative To Fertilizers?" (PDF). Hacettepe Journal of Biology and Chemistry. 39 (1): 29–38. Retrieved 23 March 2015
 * 7) ^ Jump up to:a b
 * 8) ^
 * 9) ^ Jason P. Dunion; Christopher S. Velden (2004). "The impact of the Saharan Air Layer on Atlantic tropical cyclone activity". Bulletin of the American Meteorological Society. American Meteorological Society. 85 (3): 353–366. doi:10.1175/BAMS-85-3-353.


 * Are all facts in the article backed up by a reliable secondary source of information?
 * Are the sources thorough - i.e. Do they reflect the available literature on the topic?
 * Are the sources current?
 * Are the sources written by a diverse spectrum of authors? Do they include historically marginalized individuals where possible?
 * Check a few links. Do they work?

Sources and references evaluation
No, this article mostly references one source only without a secondary source. Some of the references are from good peer-reviewed journals, such as Geophysical Research Letters and Science. Most of the references are reliable sources, however, some are quite old. One may argue that the large scale movement of the Saharan air layer may not necessarily be a lot different in 10-20 years ago from now, however, the understanding will be more thorough with the progression of the technology, i.e., better numerical models can be used. As a result, up-to-date research papers are important.

Organization

 * Guiding questions


 * Is the article well-written - i.e. Is it concise, clear, and easy to read?
 * Does the article have any grammatical or spelling errors?
 * Is the article well-organized - i.e. broken down into sections that reflect the major points of the topic?

Organization evaluation
For the most part, this article is concise and clear, without grammatical errors, and organized. Nonetheless, the article will be better if each paragraph is coherent to its nearby paragraph. I feel the article switches subject too much from paragraphs to paragraphs, sometimes it is hard to follow.

Images and Media

 * Guiding questions


 * Does the article include images that enhance understanding of the topic?
 * Are images well-captioned?
 * Do all images adhere to Wikipedia's copyright regulations?
 * Are the images laid out in a visually appealing way?

Images and media evaluation
The article includes some satellite images that help visualize the large scale dust distribution. Figure captions only provide a short description of the location. The things that should also be included are the specific time and which satellite they have used.

Nonetheless, the figures are quite appealing.

Checking the talk page

 * Guiding questions

Untitled[edit]
Comparing eight million tons of sand to eight million pickups weighing one ton each. Wow. It takes a NASA researcher with a doctor's title to acheive this. --- Seriously, I'd remove the quote. It explains nothing. If you cannot imagine the weight of eight tons, you probably cannot imagine eight million pickups. --213.39.211.206 10:15, 28 September 2007 (UTC)

If someone could calculate the size of the cube that amount of sand would take up, that might be impressing. --213.39.169.43 10:19, 28 September 2007 (UTC)

Saharan dust delivered by the SAL to the Americas[edit]
The Saharan Air Layer carries dust which includes mostly amorphous silica caused by strong winds channeled by nearby mountains rolling gravel in the Bodele depression composed of tiny miocrobe shells left from when the depression was a large lake. Other ingredients include iron and aspergillus.

The temperature inversion of the Saharan Air Layer delivers the dust to the Puerto Rico and the rest of the Americas with a minimum of vertical mixing, causing raised fine particles readings.

http://www.ssd.noaa.gov/PS/FIRE/GASP/AOD/latest_US.jpg —Preceding unsigned comment added by 66.167.61.160 (talk) 00:31, 9 August 2009 (UTC)


 * What kinds of conversations, if any, are going on behind the scenes about how to represent this topic?
 * How is the article rated? Is it a part of any WikiProjects?
 * How does the way Wikipedia discusses this topic differ from the way we've talked about it in class?

Talk page evaluation
People suggested to change some wording. And suggesting to add more about delivery of Saharan dust to the America.

This article is of interest to some WikiProjects: WikiProject Meteorology, WikiProject Africa/ Western Sahara and WikiProject Tropical cyclones.

I think the class has not talked about the aerosol so far.

Overall impressions

 * Guiding questions


 * What is the article's overall status?
 * What are the article's strengths?
 * How can the article be improved?
 * How would you assess the article's completeness - i.e. Is the article well-developed? Is it underdeveloped or poorly developed?

Overall evaluation
The article's overall status is rated Start-class. The article has a great potential to expand and develop, and the issue will be more and more popular because of climate change.

To make this article more successful and more informative, more reliable and up-to-date citations should be included. In addition, some other aspects of SAL should be included, such as how SAL can influence the marine ecosystem at the open ocean or the coast. This article is for sure underdeveloped, much work should be done.

Optional activity

 * Choose at least 1 question relevant to the article you're evaluating and leave your evaluation on the article's Talk page. Be sure to sign your feedback

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