This region of China also includes Hong Kong, and so has seen much urban expansion in the late twentieth century. Weng showed that the spatial pattern of radiant temperature increase correlated well with the pattern of urban development. The total increase of radiant surface temperature in the urbanized areas was 13.01°C. Weng also found that the urban expansion was uneven and that the effect of a major road on the location of urban growth and development was fairly substantial; with 66% of urban expansion happening within 2000m of a major road.
The environmental impacts of urban sprawl are felt everywhere and Weng's study can provide valuable insight on using GIS and remote sensing on the effects of urban sprawl on habitat encroachment. A problem with this study did arise however: the effects of surface roughness on radiant surface temperature were not taken into account. Accurate land surface temperature can be found only after its relationship to the component temperatures has been mathematically modeled and taken into account.
Weng, Q. Q. (2001). A remote sensing–GIS evaluation of urban expansion and its impact on surface temperature in the Zhujiang Delta, China. International Journal Of Remote Sensing, 22(10), 1999-2014. doi:10.1080/01431160152043676
This blog reminds me of a blog I posted about Micro-Urban Heat Islands. There was a rise in micro-urban heat islands in Dallas, TX because of the expansion of urbanization growth throughout the city. Shade trees got chopped down and because of this the lack of shade over buildings, homes, parking lots, etc. resulted in hot spots where there was temperature increase, making it more difficult to cool areas and using more energy to do so. I think this problem will be one that we will continue to see in the future.
ReplyDelete13.01 °C is a huge jump in temperature (that's 55° Fahrenheit!), which is shocking. It makes sense that this issue would be so highly influenced by major roadways, but I didn't put that together until this blog post, so it's neat that GIS was used so effectively.
ReplyDeleteI wonder if this increase in temperature remains constant through out the year, or if it is exacerbated in periods of extreme heat. Since the concrete contains heat, it surely would heighten the effects of a heat wave, but would it remain constant? Or heat up exponentially (since the land wouldn't have time to cool off). I also wonder what innovations are being developed to address this issue! Perhaps other building materials? A focus on green spaces and trees throughout the city? Mass transit versus individual cars? GIS probably could be used to figure out the best way to address heat islands and I am curious to find out what has been discovered!
I like the fact the GIS allows a person to visually understand this phenomenon. I feel like the maps pictured above are a solid way to comprehend and hopefully address the issue. I also think it is interesting that temperature increases appear to spread well beyond the expansion areas.
ReplyDeleteThe increased urbanization and temperature spikes have probably decreased rainfall in the surrounding ares which causes more areas of temperature increase. This could be bad for the wildlife and forested areas near pockets of large temperature increase because water wouldn't be as available. A possible solution to their problem could be expanding upwards and building taller buildings instead of creating more city sprawl.
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