The carbon isotopic ratio of atmospheric carbon dioxide at Tsukuba, Japan

✍ Scribed by Hisayuki Inoue; Yukio Sugimura

• Publisher: Springer Netherlands
• Year: 1985
• Tongue: English
• Weight: 613 KB
• Volume: 2
• Category: Article
• ISSN: 0167-7764
• DOI: 10.1007/bf00130746

✦ Synopsis

To find out the secular and seasonal trends of the 8t3C value and CO 2 concentration in the surface air and the determination of the ~ 13C in the atmospheric CO 2 collected at Tsukuba Science City was carried out during the period from July 1981 to October 1983. The monthly average of the 6~3C value of CO s in the surface air collected at 1400 LMT ranged from-7.52 to -8.45%0 with an average of -7.96 _+ 0.25%0 and the CO s concentration in the air varied from 334.5 ul 1-1 to 359 #1 1-1 with an average of 347.2 ~+ 6.3 tal 1-1 . The ~ ~3 C value is high in summer and low in winter and is negatively correlated with the CO 2 concentration. In general, the relationship between the 613C and the CO 2 concentration is explainable by a simple mixing model of two different constant carbon isotopic species but the relationship does not always follow the model. The correlation between the /~ ~3C value and the CO 2 concentration is low during the plant growth season and high at other times. The observed negative deviation of the ~ 13C value from the simple mixing model in the plant growth season is partly due to the isotopic fractionation process which takes place in the land biota.