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The influence of urban design on outdoor thermal comfort in the hot, humid city of Colombo, Sri Lanka

Johansson, Erik LU and Emmanuel, Rohinton (2006) In International Journal of Biometeorology 51(2). p.119-133
Abstract
The outdoor environment is deteriorating in many tropical cities due to rapid urbanization. This leads to a number of problems related to health and well-being of humans and also negatively affects social and commercial outdoor activities. The creation of thermally comfortable microclimates in urban environments is therefore very important. This paper discusses the influence of street-canyon geometry on outdoor thermal comfort in Colombo, Sri Lanka. Five sites with different urban geometry, ground cover, and distance from the sea were studied during the warmest season. The environmental parameters affecting thermal comfort, viz. air temperature, humidity, wind speed, and solar radiation, were measured, and the thermal comfort was estimated... (More)
The outdoor environment is deteriorating in many tropical cities due to rapid urbanization. This leads to a number of problems related to health and well-being of humans and also negatively affects social and commercial outdoor activities. The creation of thermally comfortable microclimates in urban environments is therefore very important. This paper discusses the influence of street-canyon geometry on outdoor thermal comfort in Colombo, Sri Lanka. Five sites with different urban geometry, ground cover, and distance from the sea were studied during the warmest season. The environmental parameters affecting thermal comfort, viz. air temperature, humidity, wind speed, and solar radiation, were measured, and the thermal comfort was estimated by calculating the physiologically equivalent temperature (PET). The thermal comfort is far above the assumed comfort zone due to the combination of intense solar radiation, high temperatures, and low wind speeds, especially on clear days. The worst conditions were found in wide streets with low-rise buildings and no shade trees. The most comfortable conditions were found in narrow streets with tall buildings, especially if shade trees were present, as well as in areas near the coast where the sea breeze had a positive effect. In order to improve the outdoor comfort in Colombo, it is suggested to allow a more compact urban form with deeper street canyons and to provide additional shade through the use of trees, covered walkways, pedestrian arcades, etc. The opening up of the city's coastal strip would allow the sea breeze to penetrate further into the city. (Less)
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author
and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Colombo, climate, hot humid, urban design, outdoor thermal comfort, urban microclimate
in
International Journal of Biometeorology
volume
51
issue
2
pages
119 - 133
publisher
Springer
external identifiers
  • wos:000241749900004
  • scopus:33750567767
ISSN
1432-1254
DOI
10.1007/s00484-006-0047-6
language
English
LU publication?
yes
id
b6492db5-1d49-4ae6-b945-232982788c2b (old id 378396)
date added to LUP
2016-04-01 16:59:26
date last changed
2023-11-14 15:48:29
@article{b6492db5-1d49-4ae6-b945-232982788c2b,
  abstract     = {{The outdoor environment is deteriorating in many tropical cities due to rapid urbanization. This leads to a number of problems related to health and well-being of humans and also negatively affects social and commercial outdoor activities. The creation of thermally comfortable microclimates in urban environments is therefore very important. This paper discusses the influence of street-canyon geometry on outdoor thermal comfort in Colombo, Sri Lanka. Five sites with different urban geometry, ground cover, and distance from the sea were studied during the warmest season. The environmental parameters affecting thermal comfort, viz. air temperature, humidity, wind speed, and solar radiation, were measured, and the thermal comfort was estimated by calculating the physiologically equivalent temperature (PET). The thermal comfort is far above the assumed comfort zone due to the combination of intense solar radiation, high temperatures, and low wind speeds, especially on clear days. The worst conditions were found in wide streets with low-rise buildings and no shade trees. The most comfortable conditions were found in narrow streets with tall buildings, especially if shade trees were present, as well as in areas near the coast where the sea breeze had a positive effect. In order to improve the outdoor comfort in Colombo, it is suggested to allow a more compact urban form with deeper street canyons and to provide additional shade through the use of trees, covered walkways, pedestrian arcades, etc. The opening up of the city's coastal strip would allow the sea breeze to penetrate further into the city.}},
  author       = {{Johansson, Erik and Emmanuel, Rohinton}},
  issn         = {{1432-1254}},
  keywords     = {{Colombo; climate; hot humid; urban design; outdoor thermal comfort; urban microclimate}},
  language     = {{eng}},
  number       = {{2}},
  pages        = {{119--133}},
  publisher    = {{Springer}},
  series       = {{International Journal of Biometeorology}},
  title        = {{The influence of urban design on outdoor thermal comfort in the hot, humid city of Colombo, Sri Lanka}},
  url          = {{http://dx.doi.org/10.1007/s00484-006-0047-6}},
  doi          = {{10.1007/s00484-006-0047-6}},
  volume       = {{51}},
  year         = {{2006}},
}