Carbon monoxide (CO) and ethane (C<sub>2</sub>H<sub>6</sub>) trends from ground-based solar FTIR measurements at six European stations, comparison and sensitivity analysis with the EMEP model
Abstract:Abstract. Trends in the CO and C 2 H 6 partial columns (∼0-15 km) have been estimated from four European groundbased solar FTIR (Fourier Transform InfraRed) stations for the 1996-2006 time period. The CO trends from the four stations Jungfraujoch, Zugspitze, Harestua and Kiruna have been estimated to −0.45 ± 0.16 % yr −1 , −1.00 ± 0.24 % yr −1 , −0.62 ± 0.19 % yr −1 and −0.61 ± 0.16 % yr −1 , respectively. The corresponding trends for C 2 H 6 are −1.51± 0.23 % yr −1 , −2.11 ± 0.30 % yr −1 , −1.09 ± 0.25 % yr −… Show more
“…Ethane concentrations have continuously declined since the 1980s, which can be explained by reduced fossil-fuel-related emissions (Aydin et al, 2011;Simpson et al, 2012;. Negative ethane trends for 1996-2006 are also reported by Angelbratt et al (2011) from FTIR observations at four European NDACC stations. The recent ethane trend reversal identified at the Zugspitze observatory is also observed at the high-altitude NDACC station of Jungfraujoch, Swiss Alps (Franco et al, 2015).…”
Section: Results Of Long-term Trend Analysismentioning
Abstract. Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47 • N, 11 • E; 2964 m a.s.l.) and at Lauder (45 • S, 170 • E; 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6. 2 [5.6, 6.9] ppb yr −1 (parts-per-billion per year) at the Zugspitze and 6.0 [5.3, 6.7] ppb yr −1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as a tracer for thermogenic methane emissions. and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio (EMR) of 12-19 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr −1 along with an overall methane emission increase of 24-45 Tg yr −1 . Based on these results, the oil and natural gas emission contribution (C) to the renewed methane increase is deduced using three different emission scenarios with dedicated EMR ranges. Reference scenario 1 assumes an oil and gas emission combination with EMR = 7.0-16.2 %, which results in a minimum contribution C > 39 % (given as lower bound of 95 % confidence interval). Beside this most plausible scenario 1, we consider two less realistic limiting cases of pure oil-related emissions (scenario 2 with EMR = 16.2-31.4 %) and pure natural gas sources (scenario 3 with EMR = 4.4-7.0 %), which result in C > 18 % and C > 73 %, respectively. Our results suggest that long-term observations of columnaveraged ethane provide a valuable constraint on the source attribution of methane emission changes and provide basic knowledge for developing effective climate change mitigation strategies.
“…Ethane concentrations have continuously declined since the 1980s, which can be explained by reduced fossil-fuel-related emissions (Aydin et al, 2011;Simpson et al, 2012;. Negative ethane trends for 1996-2006 are also reported by Angelbratt et al (2011) from FTIR observations at four European NDACC stations. The recent ethane trend reversal identified at the Zugspitze observatory is also observed at the high-altitude NDACC station of Jungfraujoch, Swiss Alps (Franco et al, 2015).…”
Section: Results Of Long-term Trend Analysismentioning
Abstract. Harmonized time series of column-averaged mole fractions of atmospheric methane and ethane over the period 1999-2014 are derived from solar Fourier transform infrared (FTIR) measurements at the Zugspitze summit (47 • N, 11 • E; 2964 m a.s.l.) and at Lauder (45 • S, 170 • E; 370 m a.s.l.). Long-term trend analysis reveals a consistent renewed methane increase since 2007 of 6. 2 [5.6, 6.9] ppb yr −1 (parts-per-billion per year) at the Zugspitze and 6.0 [5.3, 6.7] ppb yr −1 at Lauder (95 % confidence intervals). Several recent studies provide pieces of evidence that the renewed methane increase is most likely driven by two main factors: (i) increased methane emissions from tropical wetlands, followed by (ii) increased thermogenic methane emissions due to growing oil and natural gas production. Here, we quantify the magnitude of the second class of sources, using long-term measurements of atmospheric ethane as a tracer for thermogenic methane emissions. and can be assigned to thermogenic methane emissions with an ethane-to-methane ratio (EMR) of 12-19 %. We present optimized emission scenarios for 2007-2014 derived from an atmospheric two-box model. From our trend observations we infer a total ethane emission increase over the period 2007-2014 from oil and natural gas sources of 1-11 Tg yr −1 along with an overall methane emission increase of 24-45 Tg yr −1 . Based on these results, the oil and natural gas emission contribution (C) to the renewed methane increase is deduced using three different emission scenarios with dedicated EMR ranges. Reference scenario 1 assumes an oil and gas emission combination with EMR = 7.0-16.2 %, which results in a minimum contribution C > 39 % (given as lower bound of 95 % confidence interval). Beside this most plausible scenario 1, we consider two less realistic limiting cases of pure oil-related emissions (scenario 2 with EMR = 16.2-31.4 %) and pure natural gas sources (scenario 3 with EMR = 4.4-7.0 %), which result in C > 18 % and C > 73 %, respectively. Our results suggest that long-term observations of columnaveraged ethane provide a valuable constraint on the source attribution of methane emission changes and provide basic knowledge for developing effective climate change mitigation strategies.
“…This underscores the importance of maintaining consistent long-term CO observations. Using CO measurements from 1996 to 2007, both Zellweger et al (2009) and Angelbratt et al (2011) find decreasing trends for CO in Europe. The most comparable measurements to satellite total column CO measurements are those of Angelbratt et al (2011) (EPA, 2011).…”
Section: Trend Evaluationmentioning
confidence: 99%
“…Using CO measurements from 1996 to 2007, both Zellweger et al (2009) and Angelbratt et al (2011) find decreasing trends for CO in Europe. The most comparable measurements to satellite total column CO measurements are those of Angelbratt et al (2011) (EPA, 2011). This corresponds to −5.2 % yr −1 , which is larger than the MOPITT trend for E. USA, (−1.4 ± 0.2) % yr −1 , but surface CO, measured at mostly urban sites, would be expected to show larger changes compared to total column CO.…”
Abstract. Atmospheric carbon monoxide (CO) distributions are controlled by anthropogenic emissions, biomass burning, transport and oxidation by reaction with the hydroxyl radical (OH). Quantifying trends in CO is therefore important for understanding changes related to all of these contributions. Here we present a comprehensive record of satellite observations from 2000 through 2011 of total column CO using the available measurements from nadir-viewing thermal infrared instruments: MOPITT, AIRS, TES and IASI. We examine trends for CO in the Northern and Southern Hemispheres along with regional trends for Eastern China, Eastern USA, Europe and India. We find that all the satellite observations are consistent with a modest decreasing trend ∼ −1 % yr −1 in total column CO over the Northern Hemisphere for this time period and a less significant, but still decreasing trend in the Southern Hemisphere. Although decreasing trends in the United States and Europe have been observed from surface CO measurements, we also find a decrease in CO over E. China that, to our knowledge, has not been reported previously. Some of the interannual variability in the observations can be explained by global fire emissions, but the overall decrease needs further study to understand the implications for changes in anthropogenic emissions.
“…For ozone the lateral boundary concentrations are based on ozone climatology scaled by measurements from the clean sector at Mace Head, Ireland, unaffected by European emissions. A detailed description of the model can be found in Simpson et al (2012) Colette et al, 2011Colette et al, , 2012Angelbratt et al, 2011).…”
Abstract. Land-based emissions of air pollutants in Europe have steadily decreased over the past two decades, and this decrease is expected to continue. Within the same time span emissions from shipping have increased in EU ports and in the Baltic Sea and the North Sea, defined as SECAs (sulfur emission control areas), although recently sulfur emissions, and subsequently particle emissions, have decreased. The maximum allowed sulfur content in marine fuels in EU ports is now 0.1 %, as required by the European Union sulfur directive. In the SECAs the maximum fuel content of sulfur is currently 1 % (the global average is about 2.4 %). This will be reduced to 0.1 % from 2015, following the new International Maritime Organization (IMO) rules.In order to assess the effects of ship emissions in and around the Baltic Sea and the North Sea, regional model calculations with the EMEP air pollution model have been made on a 1/4 • longitude × 1/8 • latitude resolution, using ship emissions in the Baltic Sea and the North Sea that are based on accurate ship positioning data. The effects on depositions and air pollution and the resulting number of years of life lost (YOLLs) have been calculated by comparing model calculations with and without ship emissions in the two sea areas. In 2010 stricter regulations for sulfur emissions were implemented in the two sea areas, reducing the maximum sulfur content allowed in marine fuels from 1.5 to 1 %. In addition ships were required to use fuels with 0.1 % sulfur in EU harbours. The calculations have been made with emissions representative of 2009 and 2011, i.e. before and after the implementation of the stricter controls on sulfur emissions from 2010. The calculations with present emissions show that per person, an additional 0.1-0.2 years of life lost is estimated in areas close to the major ship tracks with current emission levels. Comparisons of model calculations with emissions before and after the implementation of stricter emission control on sulfur show a general decrease in calculated particle concentration. At the same time, however, an increase in ship activity has resulted in higher emissions of other components, and subsequently air concentrations, in particular of NO x , especially in and around several major ports.Additional model calculations have been made with landbased and ship emissions representative of year 2030. Following a decrease in emissions from all sectors, air quality is expected to improve, and depositions to be reduced. Particles from shipping are expected to decrease as a result of emission controls in the SECAs. Further controls of NO x emissions from shipping are not decided, and calculations are presented with and without such controls.
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