Shuang-Xi Fang

Chinese Academy of Meteorological Sciences, Peping, Beijing, China

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Publications (12)6.56 Total impact

  • Shuang-xi Fang · Pieter P. Tans · Fan Dong · Huaigang Zhou · Tian Luan
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    ABSTRACT: Atmospheric CO2 and CH4 have been continuously measured at the Shangdianzi regional background station (SDZ) in China from 2009 to 2013. Based on the influences of local surface wind and long-distance transport, the observed records were flagged into locally influenced, Beijing-Tianjin-Hebei (BTH) influenced, and Russia, Mongolia, and Inner Mongolia autonomous region influenced (RMI). ∼ 81.4% of CO2 and ∼ 75.6% of CH4 mole fractions were flagged as locally representative, indicating that the atmospheric CO2 and CH4 at SDZ were strongly influenced by local sources and sinks. Cluster analysis of back trajectories proved that the atmospheric CO2 and CH4 were influenced by air masses from northwest (RMI) or from south and southeast (BTH). The CO2 and CH4 mole fractions in BTH are always higher than in RMI, with the largest difference of 11.5 ± 0.3 ppm for CO2 and 102 ± 1 ppb for CH4 in July. The annual growth rates of CO2 and CH4 in BTH are 3.8 ± 0.01 ppm yr-1 and 10 ± 0.1 ppb yr-1, respectively, which are apparently higher than those of the RMI and the global means. The long-term trends of CO2 and CH4 in BTH are deviating from those in RMI, with ratios of ∼ 1.0 ppm yr-1 for CO2 and ∼ 2 ppb yr-1 for CH4, indicating the strengths of CO2 and CH4 emission in Beijing-Tianjin-Hebei plain increased more than 20% every year.
    No preview · Article · Jan 2016
  • Source
    Shuang-xi Fang · Tian Luan · Gen Zhang · Yanling Wu · Dajiang Yu
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    ABSTRACT: Using an appropriate method to filter the atmospheric CO2 mole fractions is not only essential to understand the long-term trend in regional areas but also to study the sources/sinks in the vicinity of the observatory, especially for regional stations where the observed records are frequently influenced by local sources/sinks. In this study, four data selection approaches are used to filter the observed atmospheric CO2 records from 2009 to 2013 at the Longfengshan (LFS) World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) regional station located in northeastern China. The methods include the methane tracer method (CT), black carbon tracer method (BC), robust extraction of the baseline signal (REBS), and meteorological method (MET). All four methods can accurately capture CO2 seasonal cycles. However, the CT and REBS induce errors on seasonal value estimations, typically in summer. The BC and MET are better to separate the CO2 mole fractions into regional or local events, but the BC slightly underestimates the regional CO2 values during the winter-spring period. In general, the MET is the most reasonable to identify the influence of local sources/sinks and is suitable to be applied at other regional stations. By using the MET, the annual growth rate of regional CO2 at LFS is calculated to be 3.0 ± 0.8 ppm yr-1 (1-σ) from 2009 to 2013.
    Full-text · Article · May 2015 · Atmospheric Environment
  • Tian Luan · Shuang-xi Fang · Ling-xi Zhou · Hong-yang Wang · Gen Zhang
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    ABSTRACT: A high precision GC system with a pulsed discharge helium ionization detector was set up based on the commercial Agilent 7890A gas chromatography. The gas is identified by retention time and the concentration is calculated through the peak height. Detection limit of the system is about 1 x 10(-9) (mole fraction, the same as below). The standard deviation of 140 continuous injections with a standard cylinder( concentration is roughly 600 x 10(-9)) is better than 0.3 x 10(-9). Between 409.30 x 10(-9) and 867.74 x 10(-9) molecular hydrogen mole fractions and peak height have good linear response. By using two standards to quantify the air sample, the precision meets the background molecular hydrogen compatibility goal within the World Meteorological Organization/Global Atmosphere Watch (WMO/GAW) program. Atmospheric molecular hydrogen concentration at Guangzhou urban area was preliminarily measured by this method from January to November 2013. The results show that the atmospheric molecular hydrogen mole fraction varies from 450 x 10(-9) to 700 x 10(-9) during the observation period, with the lowest value at 14:00 (Beijing time, the same as below) and the peak value at 20:00. The seasonal variation of atmospheric hydrogen at Guangzhou area was similar with that of the same latitude stations in northern hemisphere.
    No preview · Article · Jan 2015 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
  • Li-xin Liu · Ling-xi Zhou · Ling-jun Xia · Hong-yang Wang · Shuang-xi Fang
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    ABSTRACT: To strengthen scientific management and sharing of greenhouse gas data obtained from atmospheric background stations in China, it is important to ensure the standardization of quality assurance and quality control method for background CO2 sampling and analysis. Based on the greenhouse gas sampling and observation experience of CMA, using portable sampling observation and WS-CRDS analysis technique as an example, the quality assurance measures for atmospheric CO,sampling and observation in the Waliguan station (Qinghai), the glass bottle quality assurance measures and the systematic quality control method during sample analysis, the correction method during data processing, as well as the data grading quality markers and data fitting interpolation method were systematically introduced. Finally, using this research method, the CO2 sampling and observation data at the atmospheric background stations in 3 typical regions were processed and the concentration variation characteristics were analyzed, indicating that this research method could well catch the influences of the regional and local environmental factors on the observation results, and reflect the characteristics of natural and human activities in an objective and accurate way.
    No preview · Article · Dec 2014 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
  • Jing-Jiao Pu · Hong-Hui Xu · Jun He · Shuang-Xi Fang · Ling-Xi Zhou
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    ABSTRACT: A new method of extracting regional background concentration of CO2 in Yangtze River Delta was established based on the observations of both black carbon concentration and meteorological parameters. The concentrations of CO2 and black carbon were observed at Lin'an regional background station from 2009 to 2011. The regional background concentration of CO2 in Yangtze River Delta was obtained by means of this new method, and the impact of human activities on CO2 concentration in this area was also assessed. The results showed that the regional background concentration of CO2 extracted by this approach was comparable to the values obtained by R statistical filter method, and moreover this new method was better at picking up episodes heavily polluted by anthropogenic emissions. The annual regional average background concentration of CO2 in Yangtze River Delta from 2009 to 2011 was approximately 404.7 ± 8.2 ppm, 405.6 ± 5.3 ppm and 407.0 ± 5.3 ppm, respectively, much higher than global average value, indicating the distinct characteristic of this region. The anthropogenic emissions from Yangtze River Delta had significant influence on the concentration of CO2, increasing the value roughly 9.1 ppm higher than the regional background concentration of this area.
    No preview · Article · Sep 2014 · Atmospheric Environment
  • Tian Luan · Ling-Xi Zhou · Shuang-Xi Fang · Bo Yao · Hong-Yang Wang · Zhao Liu
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    ABSTRACT: Based on the in-situ observation results of atmospheric CO2 molar fractions at two levels (10 m and 80 m above the ground) at Longfengshan (LFS) regional background station in Heilongjiang Province during January 2009 to December 2011, this study mainly focused on the results from 10 m above the ground level (a. g. l.). The results indicated that the observed data from 10 m were strongly affected by the local sources/sinks. The differences between the 10 m and 80 m results were relatively small during the daytime (08:00-17:00) with values smaller than (0.5 +/- 0.5) x 10(-6). In spring, summer and winter, higher CO2 molar fractions were observed when surface winds came from the E-ESE-SE-SSE sectors, while, in winter, surface winds from the N-NNW-NW-WNW sectors obviously enhanced the observed values. Generally, lower CO2 values were accompanied with higher wind speed in the four seasons. This phenomenon was most obvious in winter. Based on the analysis of the observed diurnal cycles and the local meteorological conditions, the observed data from 10 m were filtered into background/non-background events. About 30.7% valid hourly data were filtered as regional background representative. The background CO2 variation displayed a peak in winter and a valley in summer with a seasonal peak to peak amplitude of (36.3 +/- 1.4) x 10(-6), which was higher than the values at similar latitude from Marine Boundary Layer (MBL) References and WMO/GAW stations. The yearly CO2 increasing rate at LFS was roughly estimated to be 2.4 x 10(-6) a(-1).
    No preview · Article · Aug 2014 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
  • Shuang-Xi Fang · Ling-Xi Zhou · Tian Luan · Qian-Li Ma · Hong-Yang Wang
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    ABSTRACT: Background CO mole fractions were continuously measured at Lian'an background station in Zhejiang province from September, 2010 to February, 2012 using Cavity Ring Down Spectroscopy (CRDS) system. The diurnal variation of CO was strongly influenced by anthropogenic activities with two peaks occurring at 07:00-10:00 and 19:00-20:00 (local time). The average daily mole fraction and amplitude in summer were the lowest among four seasons with values of 314.3 x 10(-9) +/- 7.6 x 10(-9) (mole fraction, the same below) and 50.1 x 10(-9) +/- 47.9 x 10(-9), respectively. The seasonal variations displayed peak values during winter-spring period and valley in summer, which roughly consisted with those observed variations at other sites located at northern hemisphere such as Jungfraujoch in Switzerland and Waliguan in China. However, the average mole fractions were much higher than those from other stations. The amplitude of monthly CO mole fractions was 286.8 x 10(-9) +/- 19.2 x 10(-9). The cluster analysis of backward trajectories and surface wind influence might suggest that the non-background CO mole fractions at Lin'an station were mainly affected by the emissions from the megacities and industrial area on the N-NNE-ENE sectors. The maximum enhancements in spring, summer and winter all occurred on ENE sector, with a maximum value of 106.3 x 10(-9) +/- 58.0 x 10(-9) in winter.
    No preview · Article · Jul 2014 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
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    ABSTRACT: The real-time, automatic, highly accurate and efficient system for measuring the mixing ratios of CO2, CH4, CO and N2O has been developed by combining the commercial FTIR system (Wollongong University) with an auto-sampling system and a working standard module. Based on the tests conducted, the FTIR showed the high precision and a relatively low accuracy associated with its poor determination of correction factors. The absolute error of the mixing ratio of CO was above 38.8 x 10(-9), suggesting that FTIR alone could not meet the requirement for the real time measurement. Using the working standard gases to adjust results from the FTIR significantly improved the accuracy of measurements. For both static and dynamic conditions, the discrepancies between the measured results and the real values were below 0.11 x 10(-6), 1.8 x 10(-9), 0.15 x 10(-9) and 0.5 x 10(-9) for CO2, CH4, N2O and CO respectively, meeting the requirements for the atmospheric real-time measurements. During 6 days in-situ measurements of greenhouse gas outside the lab, the precision of target gas can reach 0.05 x 10(-6), 0.2 x 10(-9), 0.07 x 10(-9), 0.5 x 10(-9) for CO2, CH4, N2O, CO, and inaccuracy can be 0.09 x 10(-6), 0.4 x 10(-9), 0.14 x 10(-9), 0.5 x 10(-9), respectively.
    No preview · Article · Nov 2013 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
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    ABSTRACT: Impacts of surface wind direction, surface wind speed, surface air temperature and sunshine hours on the CH4 concentration at Lin'an regional atmospheric background station were studied based on the results from Jan. 2009 to Dec. 2011. The results revealed that the diurnal variation of atmospheric CH4 concentration presented a single-peak curve at Lin'an regional background station. The diurnal amplitude varied from 19.0 x 10(-9) to 74.7 x 10(-9), with the lowest value observed in the afternoon and the highest at dawn. The monthly mean CH4 concentrations varied from 1955.7 x 10(-9) to 2036.2 x 10(-9), with the highest concentration observed in autumn and the lowest in spring. The wind directions NE-SSE could induce higher CH4 concentrations while SW-NNW wind directions had negative effects on the observed results. The CH4 concentration turned out to be lower with higher surface wind speed. With the increase of surface air temperature or sunshine hours, the CH4 concentration went up first till reaching a peak, and then decreased.
    No preview · Article · Mar 2013 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
  • Shuang-Xi Fang · Ling-Xi Zhou · Lin Xu · Bo Yao · Li-Xin Liu · Ling-Jun Xia · Hong-Yang Wang
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    ABSTRACT: Background CH4 concentrations were continuously measured at the 4 WMO/GAW stations [Waliguan in Qinghai (WLG), Lin'an in Zhejiang (LAN), Shangdianzi in Beijing (SDZ), and Longfengshan in Heilongjiang (LFS)] by Cavity Ring Down Spectroscopy system. From 2009 to 2010, the diurnal cycle of hourly average CH4 concentration at LAN was found to be similar in all four seasons, with the highest level detected at 05:00 (Beijing Time) and the lowest at about 14:00. Similar CH4 diurnal cycles were observed at LFS in the summer time. However, the daily amplitude was much higher than that at LAN and reached 216. 8 x 10(-9) (molar ratio). For SDZ station, there were similar trends in spring, autumn and winter. The daily average concentration in the summer was much higher than those of the other seasons and reached the highest at about 20:00. No apparent CH4 diurnal cycle was observed at the WLG station during the whole year. The seasonal variations were obvious at the three regional stations (LAN, SDZ, LFS). The background concentration was the lowest in July at LAN while reached the highest level in August at LFS. The yearly background concentration variation at LFS displayed a "W" pattern. At LFS and SDZ, the wintertime CH4 concentrations were higher than those in spring and autumn. WLG represented a clean area and its CH4 value was the lowest among the four stations with the monthly average amplitude to be about 11.5 x 10(-9). At all three regional stations, non-background data accounted for more than 70% of the whole data. Cluster analysis of 3 day backward trajectories corresponding to the high CH4 concentration (WLG: CH4 > 1 870 x 10(-9), LFS: CH4 > 2100 x 10(-9), LAN: CH4 > 2 150 x10(-9), SDZ: CH4 > 2050 x 10(-9)) data points suggested that the high CH4 level measured in summer might be associated with the air mass transportation.
    No preview · Article · Sep 2012 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
  • Wei Wang · Ling-Xi Zhou · Shuang-Xi Fang · Fang Zhang · Bo Yao · Li-Xin Liu
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    ABSTRACT: In-situ GC-FID system for atmospheric CH4 and CO mixing ratio measurements at the Shangdianzi (SDZ) GAW regional station in Beijing was designed and optimized in 2009 based on a comparable system at the Waliguan GAW global station in Qinhai. Results from this study indicate that the system's precisions for CH4 and CO are higher than 0.03% and 0.45% respectively, which can meet the quality target on background greenhouse gas observations by the World Meteorology Organization's Global Atmosphere Watch (WMO/GAW) program. The selection method of working standards for this system was established: two working standards (WH for the high concentration and WL for the low concentration) were selected, the concentrations of CH4 and CO in these two standards can cover the ambient mixing ratios of CH4 (2 007.1 x 10(-9) and 1 809.5 x 10(-9)) and CO (405.6 x 10(-9) and 123.8 x 10(-9)), an injection sequence was programmed so that the two standards were analyzed alternatively for every three runs. The measurement accuracies are high, as shown by the standard deviations less than 1.7 x 10(-9) and 1 x 10(-9), for CH4 and CO, respectively. This method has been applied to in-situ measurement of atmospheric CH4 and CO in North China.
    No preview · Article · Jan 2012 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]
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    ABSTRACT: To strengthen scientific management and sharing of greenhouse gas data obtained from atmospheric background stations in China, it is important to ensure the standardization of observations and establish the data treatment and quality control procedure so as to maintain consistency in atmospheric carbon dioxide (CO2) and methane (CH4) measurements from different background stations. An automated gas chromatographic system (Hewlett Packard 5890GC employing flame ionization detection) for in situ measurements of atmospheric CO2 and CH4 has been developed since 1994 at the China Global Atmosphere Watch Baseline Observatory at Mt. Waliguan, in Qinhai. In this study, processing and quality control flow of CO2 and CH4 data acquired by HP ChemStation are discussed in detail, including raw data acquisition, data merge, time series inspection, operator flag, principal investigator flag, and the comparison of the GC measurement with the flask method. Atmosphere CO2 and CH4 mixing ratios were separated as background and non-background data using a robust local regression method, approximately 72% and 44% observed values had been filtered as background data for CO2 and CH4, respectively. Comparison of the CO1 and CH, in situ data to the flask sampling data were in good agreement, the relative deviations are within +/- 0.5% for CO2 and for CH4. The data has been assimilated into global database (Globalview-CO2, Globalview-CH4), submitted to the World Data Centre for Greenhouse Gases (WDCGG), and applied to World Meteorological Organization (WMO) Greenhouse Gas Bulletin and assessment reports of the United Nations Intergovernmental Panel on Climate Change (IPCC).
    No preview · Article · Oct 2010 · Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]