Changing characteristics of atmospheric CH<sub>4</sub> on the Tibetan Plateau, records from 1994 to 2017 at Mount Waliguan station

doi:10.5194/acp-2020-481

GSTDTAP > 地球科学

DOI	10.5194/acp-2020-481
	Changing characteristics of atmospheric CH₄ on the Tibetan Plateau, records from 1994 to 2017 at Mount Waliguan station
	Shuo Liu, Shuangxi Fang, Peng Liu, Miao Liang, Minrui Guo, and Zhaozhong Feng
	2020-07-29
发表期刊	Atmospheric Chemistry and Physics
出版年	2020
英文摘要	A 24-year long-term observation of atmospheric CH₄ was presented at Mt. Waliguan (WLG) station, the only WMO/GAW global station in inland of Eurasia. Overall, during 1994–2017, continuously increase of atmospheric CH₄ was observed at WLG with yearly growth rate of 5.1 ± 0.1 ppb yr⁻¹, although near-zero and even negative growth appeared in some particular periods, e.g., 1999–2000, and 2004–2006. The average CH₄ mole fraction was only 1805.8 ± 0.1 ppb in 1995, but unprecedented elevated ~ 100 ppb and reached a historic high of 1903.8 ± 0.1 ppb in 2016. The seasonal averages of atmospheric CH₄ at WLG were ordered by summer, winter, autumn and spring, and the correlation slopes of ΔCO/ΔCH₄ showed a maximum in summer and minimum in winter, which was almost opposite to other sites in the northern hemisphere, e.g., Mauna Loa, Jungfraujoch, and was caused by regional transport. Strong potential sources at WLG were predominately identified in northeast (cities, e.g., Xining, Lanzhou) and southwest (the Northern India), and air masses from west and northwest regions were accompanied with higher CH₄ mole fractions than that from city regions. What is interesting is that obviously changes appeared in different observing periods. Generally, (i) the amplitudes of diurnal or seasonal cycles were continuously increasing over time, (ii) the wind sectors with elevated CH₄ moved from ENE- ... -SSE sectors in early periods to NNE- ... -E sectors (city regions) in later years, (iii) the area of source regions was increasing along with the years, and strong sources gradually shifted from northeast to southwest, (iv) the annual growth rates in recent years (e.g., 2013–2016) were significantly larger than that in early periods (e.g., 1998–2012). We conclude that the site was more and more affected by regional sources along with the time. Northern India was possibly becoming the strongest source area to WLG rather than city regions before. The case study in the Tibetan Plateau showed that the atmospheric CH₄ observed in Qinghai-Tibetan Plateau changed not as expected, the annual growth rate was even larger than that in city regions in some period (e.g., 7.3 ± 0.1 ppb yr⁻¹ in 2013–2016). It is unambiguous that the anomalously fluctuations of atmospheric CH₄ in this region are a warning to the world, its increasingly annual growth rate may be a dangerous signal to global climate change.
领域	地球科学
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文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/286599
专题	地球科学
推荐引用方式 GB/T 7714	Shuo Liu, Shuangxi Fang, Peng Liu, Miao Liang, Minrui Guo, and Zhaozhong Feng. Changing characteristics of atmospheric CH₄ on the Tibetan Plateau, records from 1994 to 2017 at Mount Waliguan station[J]. Atmospheric Chemistry and Physics,2020.
APA	Shuo Liu, Shuangxi Fang, Peng Liu, Miao Liang, Minrui Guo, and Zhaozhong Feng.(2020).Changing characteristics of atmospheric CH₄ on the Tibetan Plateau, records from 1994 to 2017 at Mount Waliguan station.Atmospheric Chemistry and Physics.
MLA	Shuo Liu, Shuangxi Fang, Peng Liu, Miao Liang, Minrui Guo, and Zhaozhong Feng."Changing characteristics of atmospheric CH₄ on the Tibetan Plateau, records from 1994 to 2017 at Mount Waliguan station".Atmospheric Chemistry and Physics (2020).