Limits...
The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China.

Huang Q, Lu Y - Int J Environ Res Public Health (2015)

Bottom Line: The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05).Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001).Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

View Article: PubMed Central - PubMed

Affiliation: College of Geography Sciences, Nanjing Normal University, Wenyuan Road, Xianlin University District, Nanjing, 210023, China. flyingfangzi@163.com.

ABSTRACT
The Yangtze River Delta (YRD) has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA) has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI) effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime) and maximal (daytime) air temperature in the YRDUA using 41 meteorological stations observation data. The effect of the UHI on climate warming shows a large spatial variability. The average warming rates of average air temperature of huge cities, megalopolises, large cities, medium-sized cities, and small cities are 0.483, 0.314 ± 0.030, 0.282 ± 0.042, 0.225 ± 0.044 and 0.179 ± 0.046 °C/decade during the period of 1957-2013, respectively. The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05). Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001). The average warming rate of average air temperature attributable to urbanization is 0.124 ± 0.074 °C/decade in the YRDUA. Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

No MeSH data available.


Related in: MedlinePlus

Long-term trends in the yearly average air temperature for huge city (a), megalopolis (b), large city (c), medium-sized city (d), and small city (e) and the linear fit (straight lines) of the yearly average air temperature vs. year. The warming rate is the average value of several stations with the same urban size.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4555247&req=5

ijerph-12-08773-f005: Long-term trends in the yearly average air temperature for huge city (a), megalopolis (b), large city (c), medium-sized city (d), and small city (e) and the linear fit (straight lines) of the yearly average air temperature vs. year. The warming rate is the average value of several stations with the same urban size.

Mentions: The variations in the warming rate of average air temperature, urbanization, logarithm of the population, and built-up area for five urban sizes are shown as boxplots in Figure 4. Figure 5 presents the time series of the yearly average air temperature of five urban sizes for the period of 1957–2013. The average warming rate decreased from 0.483 °C/decade in the huge city, to 0.314 ± 0.030 °C/decade in the megalopolis, 0.282 ± 0.042 °C/decade in the large city, 0.225 ± 0.044 °C/decade in medium-sized city, and to 0.179 ± 0.046 °C/decade in the small city (Figure 4a). The warming rate in huge city of Shanghai showed the most significant warming trends. Conversely, sites with the lowest warming trends are mainly located in small or medium-sized cities in Anhui Province, which has a less developed economy. The average warming rate of a huge city and megalopolis is significantly higher than that of a medium-sized city and small city, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05). The gradual decrease in the warming rate showed that the UHI effect on the climate warming decreased with the decrease in the urban size (Figure 4b–d). Similar results were observed in previous studies. For example, Yang et al. [19] found that the warming rates were 0.904 °C/decade in a megalopolis, 0.742 °C/decade in a large city, 0.674 °C/decade in a medium-sized city, and 0.614 °C/decade in a small city in East China using the “observation minus reanalysis” method from 1981 to 2007. However, our warming rates were markedly lower than those observed by Yang et al. [19]. The differences could be partially attributed to the data period. The authors used data from 1981 to 2007, but we used data from 1957 to 2013. The rapid urbanization in China started in late 1978 during the reform and opening up process [40]. Therefore, the effect of the UHI was more significant over the past 30 years than over 1957–1980.


The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China.

Huang Q, Lu Y - Int J Environ Res Public Health (2015)

Long-term trends in the yearly average air temperature for huge city (a), megalopolis (b), large city (c), medium-sized city (d), and small city (e) and the linear fit (straight lines) of the yearly average air temperature vs. year. The warming rate is the average value of several stations with the same urban size.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555247&req=5

ijerph-12-08773-f005: Long-term trends in the yearly average air temperature for huge city (a), megalopolis (b), large city (c), medium-sized city (d), and small city (e) and the linear fit (straight lines) of the yearly average air temperature vs. year. The warming rate is the average value of several stations with the same urban size.
Mentions: The variations in the warming rate of average air temperature, urbanization, logarithm of the population, and built-up area for five urban sizes are shown as boxplots in Figure 4. Figure 5 presents the time series of the yearly average air temperature of five urban sizes for the period of 1957–2013. The average warming rate decreased from 0.483 °C/decade in the huge city, to 0.314 ± 0.030 °C/decade in the megalopolis, 0.282 ± 0.042 °C/decade in the large city, 0.225 ± 0.044 °C/decade in medium-sized city, and to 0.179 ± 0.046 °C/decade in the small city (Figure 4a). The warming rate in huge city of Shanghai showed the most significant warming trends. Conversely, sites with the lowest warming trends are mainly located in small or medium-sized cities in Anhui Province, which has a less developed economy. The average warming rate of a huge city and megalopolis is significantly higher than that of a medium-sized city and small city, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05). The gradual decrease in the warming rate showed that the UHI effect on the climate warming decreased with the decrease in the urban size (Figure 4b–d). Similar results were observed in previous studies. For example, Yang et al. [19] found that the warming rates were 0.904 °C/decade in a megalopolis, 0.742 °C/decade in a large city, 0.674 °C/decade in a medium-sized city, and 0.614 °C/decade in a small city in East China using the “observation minus reanalysis” method from 1981 to 2007. However, our warming rates were markedly lower than those observed by Yang et al. [19]. The differences could be partially attributed to the data period. The authors used data from 1981 to 2007, but we used data from 1957 to 2013. The rapid urbanization in China started in late 1978 during the reform and opening up process [40]. Therefore, the effect of the UHI was more significant over the past 30 years than over 1957–1980.

Bottom Line: The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05).Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001).Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

View Article: PubMed Central - PubMed

Affiliation: College of Geography Sciences, Nanjing Normal University, Wenyuan Road, Xianlin University District, Nanjing, 210023, China. flyingfangzi@163.com.

ABSTRACT
The Yangtze River Delta (YRD) has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA) has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI) effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime) and maximal (daytime) air temperature in the YRDUA using 41 meteorological stations observation data. The effect of the UHI on climate warming shows a large spatial variability. The average warming rates of average air temperature of huge cities, megalopolises, large cities, medium-sized cities, and small cities are 0.483, 0.314 ± 0.030, 0.282 ± 0.042, 0.225 ± 0.044 and 0.179 ± 0.046 °C/decade during the period of 1957-2013, respectively. The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05). Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001). The average warming rate of average air temperature attributable to urbanization is 0.124 ± 0.074 °C/decade in the YRDUA. Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

No MeSH data available.


Related in: MedlinePlus