Methane(CH4)and carbon dioxide(CO2)are the two most important greenhouse gases(GHGs).To examine the variation characteristics of CH4 and CO2 in the coastal South China Sea,atmospheric CH4 and CO2 measurements were performed in Bohe(BH),Guangdong,China,in summer 2021.By using an adaptive data analysis method,the diurnal patterns of CH4 and CO2 were clearly extracted and analysed in relation to the sea breeze(SB)and land breeze(LB),respectively.The average concentrations of CH4 and CO2 were 1876.91±31.13 ppb and 407.99±4.24 ppm during SB,and 1988.12±109.92 ppb and 421.54±14.89 ppm during LB,respectively.The values of CH4 and CO2 during SB basically coincided with the values and trends of marine background sites,showing that the BH station could serve as an ideal site for background GHG monitoring and dynamic analysis.The extracted diurnal variations in CH4 and CO2 showed sunrise high and sunset low patterns(with peaks at 5:00-7:00)during LB but mid-morning high and evening low patterns(with peaks at 9:00)during SB.The diumal amplitude changes in both CH4 and CO2 during LB were almost two to three times those during SB.Wind direction significantly modulated the diurnal variations in CH4 and CO2.The results in this study provide a new way to examine the variations in GHGs on different timescales and can also help us gain a better understanding of GHG sources and distributions in the South China Sea.

Yangyan Cheng;Ye Shan;Yuhuan Xue;Yujiao Zhu;Xinfeng Wang;Likun Xue;Yanguang Liu;Fangli Qiao;Min Zhang

Key Laboratory of Marine Sciences and Numerical Modeling,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China;Laboratory for Regional Oceanography and Numerical Modeling,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;Shandong Key Laboratory of Marine Sciences and Numerical Modeling,Qingdao 266061,China;Environment Research Institute,Shandong University,Qingdao 266237,China;Key Laboratory of Marine Geology and Metalllogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China

环境科学与工程前沿

[1]Yangyan Cheng;Ye Shan;Yuhuan Xue;Yujiao Zhu;Xinfeng Wang;Likun Xue;Yanguang Liu;Fangli Qiao;Min Zhang-.Variation characteristics of atmospheric methane and carbon dioxide in summertime at a coastal site in the South China Sea)[J].环境科学与工程前沿,2022(11):28-38

Bohe,diumal

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