The identification of the influence of heat tracing method on underground temperature in the urbanization process of Guangzhou
The intrinsic energy exchange exists between the shallow ground temperature and near-sur-face air temperature.As time progresses,surface temperature changes are propagated downwards and superimposed onto the steady-state geothermal field.Therefore,it is possible to reconstruct the history of ground surface temperature changes using the current subsurface temperature profile.To assess the combined effect of global warming and urbanization on the subsurface temperature of Guangzhou,this paper collected temperature data from Guangzhou station during 1958-2022 and conducted regression analysis and anomaly analysis.Meanwhile,the temperature-depth(T-Z)profiles of 16 observation boreholes in Guangzhou were obtained through field measurements.By conducting regression analysis on the lower section of the temperature profile,the geothermal gradient of the area and the depth of de-viation from the constant geothermal gradient were determined.Finally,the onset time and magnitude of warming were obtained by combining temperature data,and the theoretical curves of the surface warming profile in Guangzhou were derived using the analytical solution equation.The results show that the warming rate of air temperature in Guangzhou from 1958 to 2022 is 0.33℃per decade,with the onset time of warming being 1987,and the magnitude of warming being 2.6℃.The observed geo-thermal gradient in Guangzhou is 0.036℃/m,and the depth of deviation from the constant geothermal gradient is 54.8 m,essentially consistent with the analytically calculated depth of 57.6 m.The study finds that the earlier the start time of urbanization-induced surface warming,the greater the depth of deviation of subsurface temperature from the constant geothermal gradient,indicating the depth of de-viation can be used to describe the process of urbanization.
global warmingurbanizationair temperatureground temperatureGuangzhou
国家科技期刊平台
NSTL
万方数据
