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Urban Heating in China's Shenzhen Economic Zone
Tian, L., Chen, J. and Yu, S. 2013. How has Shenzhen been heated up during the rapid urban build-up process? Landscape and Urban Planning 115: 18-29.

The authors write that the "air temperature of an urban area is among the most important environmental variables for human beings," while noting that Oke (1973) had suggested fully four decades ago that "regional urbanization and industrialization [had been] more influential on the regional temperature than global warming," additionally citing Chung et al. (2004) in this regard.

What was done
Tian et al. used long-term climatic records of 1961-2010 in the Shenzhen Economic Zone (SEZ) - which they downloaded from the China Meteorological Data Sharing Service System - to assess potential urbanization-induced heating increases.

What was learned
The three researchers report that "on a global scale," according to the Intergovernmental Panel on Climate Change, the daily mean temperature "has increased by 0.13°C/decade over the last 12 years (1995-2006)," while they found that the similarly-defined warming ratio over the last 25 years was a much larger 0.45°C/decade for the SEZ, which finding they say "is consistent with other reports for the SEZ," citing Si et al. (2010) and Xie et al. (2011). In addition, they found that the daily minimum temperature appeared to be the most sensitive variable quantifying the magnitude and direction of the Urban Heat Island, and that it had increased by 2.33°C in the winter and 1.24°C in the summer over the course of their study, "in agreement with other results in the subtropics (Bai et al., 2011; Hsu and Chen, 2002; Jonsson, 2004; Zhang et al., 2010; Zhong, 1996) and in the tropics (Jauregui, 1997)."

What it means
Tian et al.'s findings that urbanization-induced warming was "more pronounced for minimal temperatures and in the wintertime" bodes well for human health, in light of the fact that real-world colder temperatures - on both a daily and seasonal basis - lead to far greater human mortality than do real-world warmer temperatures, as may be seen by perusing the many materials we have archived under the general heading of Health Effects (Temperature) in our Subject Index.

Bai, Y., Juang, J.Y. and Kondoh, A. 2011. Urban warming and urban heat islands in Taipei, Taiwan. In: D. Sc. Makoto Taniguchi (Ed.) Groundwater and Subsurface Environments: Human Impacts in Asian Coastal Cities. Plenum Press, New York, New York, USA, pp. 231-246.

Chung, U., Choi, J. and Yun, J.I. 2004. Urbanization effect on the observed change in mean monthly temperatures between 1951-1980 and 1971-2000 in Korea. Climatic Change 66: 127-136.

Hsu, H.H. and Chen, C.-T. 2002. Observed and projected climate change in Taiwan. Meteorology and Atmospheric Physics 79: 87-104.

Jauregui, E. 1997. Heat island development in Mexico City. Atmospheric Environment 31: 3821-3831.

Jonsson, P. 2004. Vegetation as an urban climate control in the subtropical city of Gaborone, Botswana. International Journal of Climatology 24: 1307-1322.

Oke, T.R. 1973. City size and the urban heat island. Atmospheric Environment 7: 769-779.

Si, P., Li, Q.-X., Li, W. and Yin, H. 2010. Urbanization-induced surface air temperature change in Shenzhen. Transactions of Atmosphere Science 33: 110-116.

Xie, M.-M., Fu, M.-C. and Wang, Y.-L. 2011. Changing trajectory of urban heat islands in Shenzhen, China. Remote Sensing, Environment and Transportation Engineering (RSETE), 2011 International Conference, 24-26 June 2011: 164-167.

Zhang, K.X., Wang, R., Shen, C.-C. and Da, L.-J. 2010. Temporal and spatial characteristics of the urban heat island during rapid urbanization in Shanghai, China. Environmental Monitoring and Assessment 169: 101-112.

Zhong, B.-L. 1996. Urban heat island effect of Shenzhen City. Meteorological Monthly 22: 23-24.

Reviewed 2 October 2013