Talk:Urban canyon

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This article was the subject of an educational assignment in 2014 Q1. Further details were available on the "Education Program:University of California, Los Angeles (UCLA)/The Atmospheric Boundary Layer (2014 Q2)" page, which is now unavailable on the wiki.

Intended Revision and Contribution[edit]

The following points are a brief look at what direction I plan to take when reviewing and contributing to this article. Much of what is known about Urban Canyons is contained within scientific studies. I aim to bring that information to light here.

An urban canyon is a basic urban surface unit that can be seen repeatedly throughout urban areas. The form of the canyon consists of the geometric combination of horizontal and vertical surfaces; the building arrangement acts as the walls and the streets is the ground.

The canyon air volume is the air contained within the walls, ground and 'lid' of the canyon, the lid being an imaginary boundary at roof level.

Asymmetric canyons are when the buildings on one side of the street are of a different height than the buildings across from them.

Researcher T. R. Oke, has done much work on studying the micro-climate present inside urban canyons, with the aim of determining the general properties of urban climate from the results found inside urban canyons.

Studies of urban canyons take into account the orientation of the canyon (being north-south, etc.), the height, length and width of the canyon. Studies within urban canyons, with regards to various temperature phenomenon, consider illumination, angle of incidence, surface albedo, emissiviy and temperature.

Furthermore, the aspect ratio and the sky view factor are important measurements. Aspect ratio (or height/width ratio) is the ratio of the average height of the buildings (on both sides) to the width of the street. Sky view factor ranges from zero to one and is calculated as the amount of sky visible when viewed from the ground up. Often a 'fish-eye' photograph is taken from the street level. A sky view factor of one denotes a completely visible sky, and zero denotes a sky blocked by obstacles. The higher the sky view factor, the quicker the urban canyon will cool, because more sky is available to absorb the heat retained by the buildings. With a low sky view factor, the canyon can retain more heat during the day, creating a higher heat release at night.

A study done by Nunez and Oke investigated the energy exchanges that happen in an urban canyon in mid-latitudes in fine summer weather. The study showed that the amount of surface energy at various times within the canyon depends on canyon geometry and orientation. Canyons with North-South orientation were found as having the floor being the most active energy site. In such a canyon, 30% of midday radiant surplus is stored in the canyon materials (the buildings). At night, the net radiant deficit (meaning the lack of solar radiation) is countered by the release of energy that was being stored in the canyon materials. This phenomenon contributes heavily to the Urban Heat Island effect.

Sources:

Kusaka, Hiroyuki and Fujio Kimura. 2004. “Thermal Effects of Urban Canyon Structure on the Nocturnal Heat Island: Numerical Experiment Using a Mesoscale Model Coupled with an Urban Canopy Model” American Meteorological Society. Vol. 43. pg. 1899-1910.

Nunez, M. And T. R. Oke. 1977. “The Energy Balance of an Urban Canyon”. Journal of Applied Meteorology. Vol. 16. pg. 11-19.

Bradley, A. V., Thornes, J. E., and Chapman L. 2001. “A method to assess the variation of urban canyon geometry from sky view factor transects” Royal Meteorological Society. Atmospheric Science Letters. doi:10.1006/asle.2001.0031.

Andreou, E. And Axarli K. 2011. “Investigation of urban canyon microclimate in traditional and contemporary environment. Experimental investigation and parametric analysis”. Elsevier Ltd. Renewable Energy Vol. 43. Pg. 354-363. doi:10.1016/j.renene.2011.11.038. Mlcrowell (talk) 15:59, 3 April 2012 (UTC)[reply]

Mlcrowell (talk) 13:49, 1 March 2012 (UTC)[reply]

At the top, I hope you're not offering commonplace traits as substitutes for the defining kind. Jim.henderson (talk) 05:11, 3 March 2012 (UTC)[reply]

Everything Mlcrowell is proposing sounds great, especially if there are sources to be cited and back this up. Blue Rasberry (talk) 23:52, 31 March 2012 (UTC)[reply]

A project to expand and restructure Urban canyon article[edit]

I'm hoping expand and restructure this article on urban canyon, for a class project. Given below is rough outline of what I'm planing to do:

A more well defined classification of Urban canyons
Explain what is named as the 'street canyon effect'
Explain how the canyon change the boundary layer wind flow
Explain how that changes in effect the air pollution dispersion at the surface
Discuss and summarize results from numerical simulations and field work that has looked in to street canyon wind flow patterns

Helpful feedback are welcome! Here is what I'm working on User:RoshiniA/sandbox

RoshiniA (talk) 21:31, 25 April 2014 (UTC)RoshiniA[reply]

Plans to move the new article online[edit]

I have been working on expanding the Urban canyon article for a class project (Education Program:University of California, Los Angeles (UCLA)/The Atmospheric Boundary Layer (2014 Q2) )and it is mostly done. I have kept almost all the facts that was in the original article and built my work abound it. A small portion of the original article was restructured/edited. We are hoping to move the new version online by the end of this months. Here is the article I'm hoping to move online User:RoshiniA/sandbox.

Any comments/thoughts on the article or about moving the article online are welcome! RoshiniA (talk) 20:37, 3 June 2014 (UTC)[reply]

Thanks for improving the article. One stylistic comment -- short bulleted lists mixed in with prose are generally discouraged in Wikipedia, instead try to work the list into the text if it's just 3 or 4 items long. We can work on that after it's published to article space, too. Please preserve the existing article's wikilinks, for example Miracle mile was linked originally but is not in your sandbox version. Also, are any of the sources you used online? Hyperlinks to source material are really useful for other editors to check the sources and perhaps further improve the article. — Brianhe (talk) 00:10, 4 June 2014 (UTC)[reply]

Urban canyons can also be used for mountain identification[edit]

Perhaps also mention urban canyons can also be used for mountain identification.[1] Jidanni (talk) 18:29, 19 January 2021 (UTC)[reply]

Wikipedia Ambassador Program course assignment[edit]

This article is the subject of an educational assignment at Mount Allison University supported by WikiProject Anthropology and the Wikipedia Ambassador Program during the 2012 Q1 term. Further details are available on the course page.

The above message was substituted from {{WAP assignment}} by PrimeBOT (talk) on 16:50, 2 January 2023 (UTC)[reply]