COMPARATIVE ANALYSIS OF GROUND-AIR TEMPERATURE DIFFERENCE BETWEEN NORTHERN GUANGDONG AND PEARL RIVER DELTA FROM 1970 TO 2021

LU Jieying; SUN Liying; WANG Chunlin; ZHANG Jing; ZHAI Zhihong; WU Jianda

doi:10.16032/j.issn.1004-4965.2023.073

Abstract：Using the daily ground temperature and air temperature data from 30 meteorological stations in northern Guangdong and the Pearl River Delta from 1970 to 2021,the present study analyzed the spatial distribution,seasonal changes,and interannual changes of ground-air temperature difference(surface temperature minus air temperature)under the background of climate change.The results show that:(1)The annual average ground-air temperature difference between northern Guangdong and the Pearl River Delta in the past 50 years is between 1.97 and 3.21℃,showing a zonal distribution pattern with higher temperature in the north and lower temperature in the south.(2)The maximum ground-air temperature difference is 3.25℃in summer and the minimum is 1.71℃in winter.The temperature difference in the Pearl River Delta in winter is larger than that in northern Guangdong,while in summer it is the opposite.(3)Dongguan in the Pearl River Delta is the city with the most obvious downward trend in winter and summer,with decline rates of 0.35℃/(10 a)and 0.66℃/(10 a),respectively.By contrast,the most obvious increase is found in Zengcheng in the Pearl River Delta and Renhua in northern Guangdong,with increase rates of 0.30℃/(10 a)and 0.32℃/(10 a),respectively.(4)In the past 50 years,the annual average ground-air temperature difference between northern Guangdong and the Pearl River Delta has shown an insignificant downward trend,with a decrease rate of 0.061℃/(10 a).An increasing trend is found in northern Guangdong with an increase rate of 0.3℃/(10 a),whereas a downward trend is found in the Pearl River Delta with a decrease rate of 0.16℃/(10 a).(5)The monthly variation of the ground-air temperature difference in northern Guangdong has a single-peak structure,while that in the Pearl River Delta has a double-peak structure.The minimum ground-air temperature difference between the two places is in March,the peak in northern Guangdong is in July,and the peak in the Pearl River Delta is in July and October.Moreover,the annual average temperature and the ground-air temperature difference in summer in the Pearl River Delta both changed abruptly in 1992.There are differences in the spatio-temporal distribution of ground-air temperature difference between northern Guangdong and the Pearl River Delta.