Study of atmospheric CH4 mole fractions at three WMO/GAW stations in China

Fang, Shuangxi; Li-hua, Zhou; Masarie, K. A.; Xu, Lin; Rella, Chris W.

doi:10.1002/jgrd.50284

Cited by 64 publications

(69 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are two modes of operation for this analyzer: a C 2 H 2 /CH 4 /H 2 O mode and a CO 2 /CH 4 /H 2 O mode. The spectroscopy of CO 2 , CH 4 and H 2 O is identical to the algorithms that are used in several standard models from the same manufacturer (e.g., models G1301, G2301, G2401); the performance of these instruments for atmospheric measurements of CO 2 , CH 4 and H 2 O has been described in detail elsewhere (Crosson, 2008;Chen et al, 2010;Winderlich et al, 2010;Rella et al, 2013;Fang et al, 2013). The basic performance reported in these papers should be highly representative of the performance of this analyzer.…”

Section: Crds Analyzermentioning

confidence: 99%

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

et al. 2015

View full text Add to dashboard Cite

Abstract. This study presents two methods for estimating methane emissions from a waste water treatment plant (WWTP) along with results from a measurement campaign at a WWTP in Valence, France. These methods, chamber measurements and tracer release, rely on Fourier transform infrared spectroscopy and cavity ring-down spectroscopy instruments. We show that the tracer release method is suitable for quantifying facility-and some process-scale emissions, while the chamber measurements provide insight into individual process emissions. Uncertainties for the two methods are described and discussed. Applying the methods to CH 4 emissions of the WWTP, we confirm that the open basins are not a major source of CH 4 on the WWTP (about 10 % of the total emissions), but that the pretreatment and sludge treatment are the main emitters. Overall, the waste water treatment plant is representative of an average French WWTP.

show abstract

Section: Crds Analyzermentioning

confidence: 99%

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Atmospheric CO 2 and CH 4 at XGL were measured using the G1301 CRDS, and CO was measured by the G1302 CRDS. Detailed information regarding the schematic of the analytical systems, air collections, calibrations, and data processing has been addressed in previous studies (Zhou et al, 2003;Fang et al, 2013). The analytical precisions for the atmospheric CO 2 , CH 4 , and CO measurements were approximately 0.07 µmol mol −1 (ppm), 1.5 nmol mol −1 (ppb), and 2.0 nmol mol −1 (ppb), respectively.…”

Section: Measurements Of Gem Co Co 2 and Chmentioning

confidence: 99%

Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

Zhang

Lin

et al. 2015

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Correlation analyses between atmospheric mercury (Hg) and other trace gases are useful for identification of sources and constraining regional Hg emissions. Emissions of Hg in Asia contribute significantly to the global budget of atmospheric Hg. However, due to the lack of reliable data on the source strength, large uncertainties remain in the emission inventories of Hg in Asia. In the present study, we calculated the correlation slopes of GEM / CO, GEM / CO 2 , and GEM / CH 4 for mainland China, South Asia, the Indochinese Peninsula, and Central Asia using the ground-based observations at three remote sites in northwestern and southwestern China, and applied these values to estimate GEM emissions in the four source regions. The geometric mean GEM / CO correlation slopes for mainland China, South Asia, the Indochinese Peninsula, and Central Asia were 7.3 ± 4.3, 7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m −3 ppb −1 , respectively, and values in the same source regions were 33.3 ± 30.4, 27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m −3 ppb −1 for the GEM / CH 4 correlation slopes, respectively. The geometric means of GEM / CO 2 correlation slopes for mainland China, South Asia, and Central Asia were 240 ± 119, 278 ± 164, 315 ± 289 pg m −3 ppm −1 , respectively. These values were the first reported correlation slopes of GEM / CO, GEM / CO 2 , and GEM / CH 4 in four important source regions of Asia, not including the GEM / CO ratios in mainland China. The correlation slopes of GEM / CO, GEM / CO 2 , and GEM / CH 4 in Asia were relatively higher than those observed in Europe, North America, and South Africa, which may highlight GEM emissions from nonferrous smelting, large-scale and artisanal mercury and gold production, natural sources, and historically deposited mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO 2 slopes, and the recently reported emission inventories of CO and CO 2 , the annual GEM emissions in mainland China, South Asia, the Indochinese Peninsula, and Central Asia were estimated to be in the ranges of 1071-1187, 340-470, 125, and 54-90 t, respectively. The estimated quantity of GEM emissions from the GEM / CH 4 correlation slopes is significantly larger, which may be due to the larger uncertainties in CH 4 emissions in Asia as well as insufficient observations of GEM / CH 4 correlation slopes, therefore leading to an overestimate of GEM emissions. Our estimates of GEM emissions in the four Asian regions were significantly higher (3-4 times) than the anthropogenic GEM emissions reported in recent studies. This discrepancy could come from a combination of reasons including underestimates of anthropogenic and natural GEM emissions; large uncertainties related to CO, CO 2 , and CH 4 emission inventories; and inherent limitations of the correlation slope method.

show abstract

“…There was no in situ CO 2 measuring system until January 2009, when a cavity ring-down spectrometer (G1301, Picarro Inc.) was installed to continuously monitor atmospheric CO 2 and CH 4 mole fractions. Since then we have been acquiring the first-hand greenhouse data at this station (Fang et al, 2013;Pu et al, 2014).…”

Section: S X Fang Et Almentioning

confidence: 99%

“…The sample air is filtered and temperature stabilized and dried to meet the high-quality target of the WMO/GAW network. Details of the system are described in Fang et al (2013). Two standard gases are used to calibrate the measurements and a target gas is used to check the precision of the system routinely.…”

Section: Measurement Systemmentioning

confidence: 99%

“…During this time of the year, a large amount of CH 4 is emitted from wetlands (e.g., from rice paddy fields) on the eastern China Plain (Lu et al, 2000;Zhang et al, 2010). Thus, these high values should represent regional conditions rather than local events (Fang et al, 2013). On the other hand, the active processes of photosynthesis by local and regional vegetation in summer reduce the observed CO 2 mole fractions, especially by local vegetation, which has a strong negative influence on the CO 2 mole fractions during afternoon.…”

Section: Mean Seasonal Cycles and Trendsmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of the regional CO2 mole fraction filtering approaches at a WMO/GAW regional station in China

et al. 2015

View full text Add to dashboard Cite

Abstract. The identification of atmospheric CO 2 observation data which are minimally influenced by very local emissions/removals is essential for trend analysis, for the estimation of regional sources and sinks, and for the modeling of long-range transport of CO 2 . In this study, four approaches are used to filter the atmospheric CO 2 observation records from 2009 to 2011 at one World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) regional station (Lin'an, LAN) in China. The methods are based on the concentration of atmospheric black carbon (BC), on a statistical approach (robust extraction of baseline signal, REBS), on CH 4 as an auxiliary tracer (AUX), and on meteorological parameters (MET). All approaches do suitably well to capture the seasonal CO 2 cycle at LAN. Differences are observed in the average regional mole fractions with annual values in the REBS method at least 1.7 ± 0.2 ppm higher than the other methods. The BC method may underestimate the regional CO 2 mole fractions during the winter-spring period and should be treated with caution. The REBS method is a purely statistical method and it may also introduce errors on the regional CO 2 mole fraction evaluations, as the filtered trend may be influenced by the "noisy" raw data series. Although there are correlations between CH 4 and CO 2 mole fractions at LAN, the different source/sink regimes may introduce bias on the regional CO 2 estimation in the AUX method, typically in summer. Overall, the MET method seems to be the most favorable because it mainly focuses on the influence of potential local sources and sinks, and considers diurnal variations and meteorological conditions. Using the MET method, the annual growth rate of regional CO 2 at LAN is determined to be 3.1 ± 0.01 ppm yr −1 (standard error) from 2009 to 2011.

show abstract

Study of atmospheric CH₄ mole fractions at three WMO/GAW stations in China

Cited by 64 publications

References 62 publications

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

Correlation slopes of GEM / CO, GEM / CO<sub>2</sub>, and GEM / CH<sub>4</sub> and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

Comparison of the regional CO<sub>2</sub> mole fraction filtering approaches at a WMO/GAW regional station in China

Contact Info

Product

Resources

About

Study of atmospheric CH4 mole fractions at three WMO/GAW stations in China

Cited by 64 publications

References 62 publications

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

Methane emission estimates using chamber and tracer release experiments for a municipal waste water treatment plant

Correlation slopes of GEM / CO, GEM / CO&lt;sub&gt;2&lt;/sub&gt;, and GEM / CH&lt;sub&gt;4&lt;/sub&gt; and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

Comparison of the regional CO&lt;sub&gt;2&lt;/sub&gt; mole fraction filtering approaches at a WMO/GAW regional station in China

Contact Info

Product

Resources

About

Study of atmospheric CH₄ mole fractions at three WMO/GAW stations in China

Correlation slopes of GEM / CO, GEM / CO<sub>2</sub>, and GEM / CH<sub>4</sub> and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

Comparison of the regional CO<sub>2</sub> mole fraction filtering approaches at a WMO/GAW regional station in China