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

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.

More Persistent Summer Compound Hot Extremes Caused by Global Urbanization

“…The pattern of urbanization contribution to DayHot is different from that to CoHot, particularly in western and parts of southeastern Europe, and western United States, where the urbanization shows slightly cooling effect on DayHot (Figures 3d–3f). Recent studies have found that local hydroclimate plays an important role in the urbanization effects (Liao et al., 2018; Lin et al., 2020), and the regional disparity in the hydroclimate conditions, such as shading, aerosols, and thermal inertia differences between urban and rural areas, could lead to different urbanization effects on daytime and nighttime temperature (Kalnay & Cai, 2003; Shen et al., 2020). However, the mechanism of urbanization effects on CoHot events is more complex and needs further study.…”

The effect of urbanization on temperature indices in the Philippines

“…For example, Shen et al . (2020) have found that in Northeast China, a significant urbanization effect was observed in T min during night‐time, whereas, a different effect was observed on T max during day time under the different changes of solar radiation; and (b) the vertical temperature profiles in the lower atmosphere (Jacobson, 1999; Fujibe, 2012). During night‐time, the formation of UHI is influenced by a strong surface inversion that originates in the sub‐urban region but is destroyed over the urban surface (Oke and East, 1971).…”

Spatiotemporal variations of seasonal temperature at different percentiles in the three provinces of northeast China from 1961 to 2019

“…Though various factors are proved to be related with global warming (Dong et al, 2014;Zhang et al, 2016;Zhang et al, 2017;Wei et al, 2018;Qiu et al, 2020;Shen et al, 2020), surface solar radiation is indubitable the most direct influencing factor for variations of Tmax, and CO 2 contributes significantly to variations of Tmin. Research shows that a CO 2 concentration increasing of 22 ppm can increase 10% of the longwave radiation, which is very important for variations of Tmin (Feldman et al, 2015).…”