Urbanization effect on the observed changes of surface air temperature in Northeast China

  • There were significant warming effect of urbanization on Tmin during the night-time
  • Urbanization had a moderate warming effects on Tmax during the solar dimming period
  • Urbanization had a weak cooling effect on Tmax during the solar stable period
Abstract

Although many studies have analyzed the effects of urbanization on temperature changes, the urbanization’s effect on temperature change remains controversial. Northeast China is the largest old industrial base in China, which experienced a rapid urbanization in the past decades. Under the background of climate change, understanding the changes of surface air temperature and urbanization effects on temperature changes in the Northeast China is important to predict climate change in China. By analyzing the historical climate data, our results suggested that minimum temperature (Tmin) over the Northeast China increased significantly (0.40°C decade-1) from 1960 to 1989, but showed no significant change (-0.02°C decade-1) during 1990 - 2016. Due to slight change of maximum temperature (Tmax), the diurnal temperature range (DTR) showed a significant decreasing trend before 1989 (-0.34°C decade-1), but reached a stable level after 1990 (-0.06°C decade-1). In Northeast China, urbanization had a significant warming effect on Tmin during the night-time, but had different effects on Tmax during the daytime under the different changes of solar radiation before and after 1990. There were moderate warming effects of urbanization on Tmax during the solar dimming period of 1960 - 1989, but weak cooling effects on Tmax during the solar stable period after 1990. Due to obvious warming effect of urbanization on Tmin, urbanization in Northeast China tends to result in an increase of mean temperature but a decrease of DTR.

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