气候变化领域集成服务门户(CCPortal): Variability in a four-network composite of atmospheric CO2 differences between three primary baseline sites

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DOI	10.5194/acp-19-14741-2019
	Variability in a four-network composite of atmospheric CO2 differences between three primary baseline sites
	Francey R.J.; Frederiksen J.S.; Paul Steele L.; Langenfelds R.L.
发表日期	2019
ISSN	16807316
起始页码	14741
结束页码	14754
卷号	19 期号:23
英文摘要	Spatial differences in the monthly baseline CO2 since 1992 from Mauna Loa (mlo, 19.5N, 155.6W, 3379m), Cape Grim (cgo, 40.7S, 144.7E, 94m), and South Pole (spo, 90S, 2810 m) are examined for consistency between four monitoring networks. For each site pair, a composite based on the average of NOAA, CSIRO, and two independent Scripps Institution of Oceanography (SIO) analysis methods is presented. Averages of the monthly standard deviations are 0.25, 0.23, and 0.16 ppm for mlo-cgo, mlo-spo, and cgo-spo respectively. This high degree of consistency and near-monthly temporal differentiation (compared to CO2 growth rates) provide an opportunity to use the composite differences for verification of global carbon cycle model simulations. Interhemispheric CO2 variation is predominantly imparted by the mlo data. The peaks and dips of the seasonal variation in interhemispheric difference act largely independently. The peaks mainly occur in May, near the peak of Northern Hemisphere (NH) terrestrial photosynthesis/respiration cycle. February-April is when interhemispheric exchange via eddy processes dominates, with increasing contributions from mean transport via the Hadley circulation into boreal summer (May-July). The dips occur in September, when the CO2 partial pressure difference is near zero. The cross-equatorial flux variation is large and sufficient to significantly influence short-term Northern Hemisphere growth rate variations. However, surface-air terrestrial flux anomalies would need to be up to an order of magnitude larger than found to explain the peak and dip CO2 difference variations. Features throughout the composite CO2 difference records are inconsistent in timing and amplitude with air-surface fluxes but are largely consistent with interhemispheric transport variations. These include greater variability prior to 2010 compared to the remarkable stability in annual CO2 interhemispheric difference in the 5-year relatively El Niño-quiet period 2010-2014 (despite a strong La Niña in 2011), and the 2017 recovery in the CO2 interhemispheric gradient from the unprecedented El Niño event in 2015-2016. © 2020 BMJ Publishing Group. All rights reserved.
语种	英语
scopus关键词	air quality; atmospheric deposition; atmospheric pollution; carbon cycle; carbon dioxide; carbon emission; El Nino; Hadley cell; seasonal variation; Antarctica; Australia; Cape Grim; East Antarctica; South Pole; Tasmania
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/143992
作者单位	CSIRO Oceans and Atmosphere, Aspendale, VIC, Australia
推荐引用方式 GB/T 7714	Francey R.J.,Frederiksen J.S.,Paul Steele L.,et al. Variability in a four-network composite of atmospheric CO2 differences between three primary baseline sites[J],2019,19(23).
APA	Francey R.J.,Frederiksen J.S.,Paul Steele L.,&Langenfelds R.L..(2019).Variability in a four-network composite of atmospheric CO2 differences between three primary baseline sites.Atmospheric Chemistry and Physics,19(23).
MLA	Francey R.J.,et al."Variability in a four-network composite of atmospheric CO2 differences between three primary baseline sites".Atmospheric Chemistry and Physics 19.23(2019).