scholarly journals Recovery and validation of Odin/SMR long term measurements ofmesospheric carbon monoxide

2020 ◽  
Author(s):  
Francesco Grieco ◽  
Kristell Pérot ◽  
Donal Murtagh ◽  
Patrick Eriksson ◽  
Peter Forkman ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Middle Atmosphere ◽  
Phase Lock Loop ◽  
Polar Regions ◽  
Line Broadening ◽  
Mixing Ratios ◽  
Correct Location ◽  
Relative Differences ◽  
Co Observations

Abstract. The Sub-Millimetre Radiometer (SMR) on board the Odin satellite performs limb sounding measurements of the middle atmosphere to detect molecular emission from different species. Carbon monoxide (CO) is an important tracer of atmospheric dynamics at these altitudes, due to its long photochemical lifetime and high vertical concentration gradient. In this study, we have successfully recovered over 18 years of SMR observations, providing the only dataset to date being so extended in time and stretching out to the polar regions, with regards to satellite-measured mesospheric CO. This new dataset is part of the Odin/SMR version 3.0 level 2 data. The much of the level 1 dataset – except the October 2003 to October 2004 period – was affected by a malfunctioning of the Phase-Lock Loop (PLL) in the frontend used for CO observations. Because of this technical issue, the CO line could be shifted away from its normal frequency location causing the retrieval to fail or leading to an incorrect estimation of the CO concentration. An algorithm was developed to locate the CO line and shift it to its correct location. Nevertheless, another artifact causing an underestimation of the concentration, i.e. a line broadening, stemmed from the PLL malfunctioning. This was accounted for by using a broader response function. The application of these corrections resulted in the recovery of a large amount of data that was previously being flagged as problematic and therefore not processed. A validation study has been carried out, showing how SMR CO volume mixing ratios are in general in good accordance with the other instruments considered in the study. Overall, the agreement is very good between 60 and 80 km altitude, with relative differences close to zero. A positive bias at low altitudes (50–60 km) up to +20 % and a negative bias up to −20 % at high altitudes (80–100 km) were found with respect to the compared instruments.

scholarly journals Recovery and validation of Odin/SMR long-term measurements of mesospheric carbon monoxide

2020 ◽  
Vol 13 (9) ◽  
pp. 5013-5031
Author(s):  
Francesco Grieco ◽  
Kristell Pérot ◽  
Donal Murtagh ◽  
Patrick Eriksson ◽  
Peter Forkman ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Middle Atmosphere ◽  
Phase Lock Loop ◽  
Polar Regions ◽  
Line Broadening ◽  
Mixing Ratios ◽  
Correct Location ◽  
Relative Differences ◽  
Co Observations

Abstract. The Sub-Millimetre Radiometer (SMR) on board the Odin satellite performs limb sounding measurements of the middle atmosphere to detect molecular emission from different species. Carbon monoxide (CO) is an important tracer of atmospheric dynamics at these altitudes, due to its long photochemical lifetime and high vertical concentration gradient. In this study, we have successfully recovered over 18 years of SMR observations, providing the only dataset to date being so extended in time and stretching out to the polar regions, with regards to satellite-measured mesospheric CO. This new dataset is part of the Odin/SMR version 3.0 level 2 data. Much of the level 1 dataset – except the October 2003 to October 2004 period – was affected by a malfunctioning of the phase-lock loop (PLL) in the front end used for CO observations. Because of this technical issue, the CO line could be shifted away from its normal frequency location, causing the retrieval to fail or leading to an incorrect estimation of the CO concentration. An algorithm was developed to locate the CO line and shift it to its correct location. Nevertheless, another artefact causing an underestimation of the concentration, i.e. a line broadening, stemmed from the PLL malfunctioning. This was accounted for by using a broader response function. The application of these corrections resulted in the recovery of a large amount of data that was previously being flagged as problematic and therefore not processed. A validation study has been carried out, showing how SMR CO volume mixing ratios are in general in good accordance with the other instruments considered in the study. Overall, the agreement is very good between 60 and 80 km altitude, with relative differences close to zero. A positive bias at low altitudes (50–60 km) up to +20 % and a negative bias up to −20 % at high altitudes (80–100 km) were found with respect to the comparison instruments.

scholarly journals Characteristics of episodes with extremely low ozone values in the northern middle latitudes 1957−2000

2001 ◽  
Vol 19 (7) ◽  
pp. 797-807 ◽  
Author(s):  
R. D. Bojkov ◽  
D. S. Balis
Keyword(s):  
Middle Atmosphere ◽  
Middle Latitude ◽  
Atmospheric Composition ◽  
Polar Regions ◽  
Term Trend ◽  
Mixing Ratios ◽  
Middle Latitudes ◽  
The Uk ◽  
Long Term Trend

Abstract. A number of episodes are observed when the total ozone for 2 to 3 days has fallen below 220 matm-cm in the northern mid- and polar latitudes in autumn. The occurrences of such episodes represent ozone deviations of about one-third from the pre-1976 Oct-Nov-Dec monthly mean! By using primarily quality checked Dobson data, a clear identification was made of more than three dozen short spells with extremely low ozone in the 1957–1978 period. In the following twenty-two years (1979–2000), using mainly TOMS data, one can identify ~ 46 cases with ozone values falling below 220 matm-cm for longer than 1 day, with each time over an area greater than 500,000 km2 . The Ozone Mass Deficiency (O3MD) from the pre-1976 average ozone values over the affected area was ~2.8 Mt per day, i.e. four to seven times greater than it would be, assuming only a long-term trend in the Oct-Nov-Dec period. The Extremely Low Ozone (ELO3) events on the day of their appearance over the N. Atlantic/European region contribute to the O3MD by representing 16% of the deficiency due to the Oct-Nov trend in the entire 40–65° N latitudinal belt. The O3MD of the greater pool with low ozone (here taken as <260 matm-cm) surrounding the area of the lowest events could contribute on the day of their appearance in Oct-Nov up to 60% and in December, ~30% to the deficiency due to the trend over the entire 40–65° N belt. Analysis of synoptic charts, supported by a backward trajectory on the isentropic surfaces 350 and 380 K, shows that in most of the events, subtropical air masses with low ozone content were transported from the Atlantic toward the UK, Scandinavia, and in many cases, further to the western sub-polar regions of Russia. This transport was sometimes combined with upward motions above a tropospheric anticyclone which lifted low ozone mixing ratios to higher altitudes. The ELO3 events cause a significant deficiency above the tropopause where, in general, the subtropical air is injected. In fact, the overall amount of ozone is not depleted, but redistributed on the hemispheric scale. Review of low ozone events, defined as days with negative deviations from the pre-1976 averages greater than 25% show, in general, similar origin. The seasonally averaged area with ELO3 and the associated O3MD, as well as for the cases with deviations > –25%, has increased during the 1990s, which could be an indication of stronger and/or more frequent subtropical air intrusions. Their occurrences could contribute noticeably to the ozone deficiency of the middle latitude ozone during the days of ELO3 appearances; however, their contribution to the long-term trend of the ozone seasonal decline is of the order of ~10%.Key words. Atmospheric composition and structure (middle atmosphere - composition and chemistry) Meteorology and atmospheric dynamics (middle atmosphere dynamics)

scholarly journals Measurement report: Long-term variations in carbon monoxide at a background station in China's Yangtze River Delta region

2020 ◽  
Author(s):  
Yijing Chen ◽  
Qianli Ma ◽  
Weili Lin ◽  
Xiaobin Xu ◽  
Jie Yao ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Control Measures ◽  
Mixing Ratios ◽  
Significant Downward Trend ◽  
The Yrd ◽  
Long Term Variations

Abstract. This study analyzed the long-term variations in carbon monoxide (CO) mixing ratios from January 2006 to December 2017 at the Lin'an regional atmospheric background station (LAN; 30.3° N, 119.73° E, 138 m a.s.l.) in China's Yangtze River Delta (YRD) region. The CO mixing ratios were at their highest (0.69 ± 0.08 ppm) and lowest (0.54 ± 0.06 ppm) in winter and summer, respectively. The average daily variation of CO exhibited a double-peaked pattern, with peaks in the morning and evening and a valley in the afternoon. A significant downward trend of −11.3 ppb/yr of CO was observed from 2006 to 2017 at the LAN station, which was in accordance with the negative trend of the average CO mixing ratios and total column retrieved from the satellite data (the Measurements Of Pollution In The Troposphere, MOPITT) over the YRD region during the same period. The average annual CO mixing ratio at the LAN station in 2017 was 0.51 ± 0.04 ppm, which was significantly lower than that (0.71 ± 0.12 ppm) in 2006. The decrease in CO levels was largest in autumn (−15.7 ppb/yr), followed by summer (−11.1 ppb/yr), spring (−10.8 ppb/yr), and winter (−9.7 ppb/yr). Moreover, the CO levels under relatively polluted conditions (the annually 95th percentiles) declined even more rapidly (−22.4 ppb/yr, α = 0.05, r = −0.68) from 2006 (0.91 ppm) to 2017 (0.58 ppm) and the CO levels under clean conditions (the annually 5th percentiles) were relatively stable throughout the years. The long-term decline and short-term variations in the CO mixing ratios at the LAN station were mainly attributed to the implementation of the anthropogenic pollution control measures in the YRD region and to the events like Shanghai Expo in 2020 and Hangzhou G20 in 2016. The decreased CO level may influence atmospheric chemistry over the region. The average OH reactivity of CO at the LAN station is estimated to significantly drop from 4.1 ± 0.7 s-1 in 2006 to 3.0 ± 0.3 s-1 in 2017.

scholarly journals Ozone, carbon monoxide and nitrogen oxides time series at four alpine GAW mountain stations in central Europe

2010 ◽  
Vol 10 (24) ◽  
pp. 12295-12316 ◽  
Author(s):  
S. Gilge ◽  
C. Plass-Duelmer ◽  
W. Fricke ◽  
A. Kaiser ◽  
L. Ries ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Anthropogenic Impacts ◽  
Vertical Mixing ◽  
Atmospheric Composition ◽  
Altitude Range ◽  
Calibration Laboratory ◽  
Central European ◽  
Mixing Ratios ◽  
Weekly Cycles

Abstract. Long-term, ground based in-situ observations of ozone (O3) and its precursor gases nitrogen dioxide (NO2) and carbon monoxide (CO) from the four sites Hohenpeissenberg and Zugspitze (D), Sonnblick (A) and Jungfraujoch (CH) are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA) procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3) or CO standards provided by the Central Calibration Laboratory (CCL) at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC) for CO and O3 (WCC-Empa; CH). Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period, 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites independent of wind sector. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the strongest O3 increase was detected in winter and lowest or even decline in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti-correlation with NO2 was found due to reduced O3 values on working days. Trends are discussed with respect to anthropogenic impacts and vertical mixing. The observed trends for NO2 at the alpine mountain sites are less pronounced than trends estimated based on emission inventories.

scholarly journals Ground-based measurements of middle-atmospheric carbon monoxide above Ny-Ålesund (78.9° N, 11.9° E)

2019 ◽  
Author(s):  
Niall J. Ryan ◽  
Mathias Palm ◽  
Christoph G. Hoffmann ◽  
Jens Goliasch ◽  
Justus Notholt
Keyword(s):  
Carbon Monoxide ◽  
Middle Atmosphere ◽  
A Priori ◽  
Optimal Estimation ◽  
Low Noise ◽  
Absolute Difference ◽  
Atmospheric Measurements ◽  
Mixing Ratios ◽  
Atmospheric Carbon ◽  
Atmospheric Carbon Monoxide

Abstract. We present a new ground-based system for measurements of middle-atmospheric carbon monoxide (CO) at Ny Ålesund, Svalbard, and the altitude profiles of CO volume mixing ratios (VMR) measured during the 2017/2018 winter. The Carbon Monoxide Radiometer for Atmospheric Measurements (CORAM) records spectra from CO emissions in the middle-atmosphere with the aid of a low-noise amplifier designed for the 230 GHz spectral region. Altitude profiles of CO VMRs are retrieved from the measured spectra using an optimal estimation inversion technique. The profiles in the current dataset have an average altitude range of 47–87 km and an estimated precision peaking at ~ 12 % of the a priori used in the inversion. The CORAM profiles are compared to collocated CO measurements from the Microwave Limb Sounder (MLS) aboard the Aura satellite and show a difference of 7.4–16.1 %, with a maximum absolute difference of 2.5 ppmv at 86 km altitude. CO profiles are currently available at 1 hr resolution between November 2017 and January 2018.

scholarly journals Measurement report: Long-term variations in carbon monoxide at a background station in China's Yangtze River Delta region

2020 ◽  
Vol 20 (24) ◽  
pp. 15969-15982
Author(s):  
Yijing Chen ◽  
Qianli Ma ◽  
Weili Lin ◽  
Xiaobin Xu ◽  
Jie Yao ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Control Measures ◽  
Mixing Ratios ◽  
Significant Downward Trend ◽  
The Yrd ◽  
Long Term Variations

Abstract. This study analyzed the long-term variations in carbon monoxide (CO) mixing ratios from January 2006 to December 2017 at the Lin'an regional atmospheric background station (LAN; 30.3∘ N, 119.73∘ E, 138 m a.s.l.) in China's Yangtze River Delta (YRD) region. The CO mixing ratios were at their highest (0.69 ± 0.08 ppm) and lowest (0.54 ± 0.06 ppm) in winter and summer, respectively. The average daily variation in CO exhibited a double-peaked pattern, with peaks in the morning and evening and a valley in the afternoon. A significant downward trend of −11.3 ppb yr−1 of CO was observed from 2006 to 2017 at the LAN station, which was in accordance with the negative trends of the average CO mixing ratios and total column retrieved from the satellite data (Measurements of Pollution in the Troposphere, MOPITT) over the YRD region during the same period. The average annual CO mixing ratio at the LAN station in 2017 was 0.51 ± 0.04 ppm, which was significantly lower than that (0.71 ± 0.12 ppm) in 2006. The decrease in CO levels was largest in autumn (−15.7 ppb yr−1), followed by summer (−11.1 ppb yr−1), spring (−10.8 ppb yr−1), and winter (−9.7 ppb yr−1). Moreover, the CO levels under relatively polluted conditions (the annual 95th percentiles) declined even more rapidly (−22.4 ppb yr−1, r=-0.68, p<0.05) from 2006 (0.91 ppm) to 2017 (0.58 ppm), and the CO levels under clean conditions (the annual 5th percentiles) showed decreasing evidence but not statistically significant (r=-0.41, p=0.19) throughout the years. The long-term decline and short-term variations in the CO mixing ratios at the LAN station were mainly attributed to the implementation of the anthropogenic pollution control measures in the YRD region and to events like the Shanghai Expo in 2010 and Hangzhou G20 in 2016. The decreased CO level may influence atmospheric chemistry over the region. The average OH reactivity of CO at the LAN station is estimated to significantly drop from 4.1 ± 0.7 s−1 in 2006 to 3.0 ± 0.3 s−1 in 2017.

scholarly journals Technical note: Inexpensive modification of Exetainers for the reliable storage of trace-level hydrogen and carbon monoxide gas samples

2021 ◽  
Vol 18 (2) ◽  
pp. 729-737
Author(s):  
Philipp A. Nauer ◽  
Eleonora Chiri ◽  
Thanavit Jirapanjawat ◽  
Chris Greening ◽  
Perran L. M. Cook
Keyword(s):  
Carbon Monoxide ◽  
Linear Increase ◽  
Technical Note ◽  
Mixing Ratios ◽  
Long Term Storage ◽  
Large Numbers ◽  
Zero Order Reaction ◽  
Low Volume ◽  
Proposed Modification

Abstract. Atmospheric trace gases such as dihydrogen (H2), carbon monoxide (CO) and methane (CH4) play important roles in microbial metabolism and biogeochemical cycles. Analysis of these gases at trace levels requires reliable storage of discrete samples of low volume. While commercial sampling vials such as Exetainers® have been tested for CH4 and other greenhouse gases, no information on reliable storage is available for H2 and CO. We show that vials sealed with butyl rubber stoppers are not suitable for storing H2 and CO due to release of these gases from rubber material. Treating butyl septa with NaOH reduced trace-gas release, but contamination was still substantial, with H2 and CO mixing ratios in air samples increasing by a factor of 3 and 10 after 30 d of storage in conventional 12 mL Exetainers. All tested materials showed a near-linear increase in H2 and CO mixing ratios, indicating a zero-order reaction and material degradation as the underlying cause. Among the rubber materials tested, silicone showed the lowest potential for H2 and CO release. We thus propose modifying Exetainers by closing them with a silicone plug to minimise contamination and sealing them with a stainless-steel bolt and O-ring as a secondary diffusion barrier for long-term storage. Such modified Exetainers exhibited stable mixing ratios of H2 and CH4 exceeding 60 d of storage at atmospheric and elevated (10 ppm) mixing ratios. The increase of CO was still measurable but was 9 times lower than in conventional Exetainers with treated septa; this can be corrected for due to its linearity by storing a standard gas alongside the samples. The proposed modification is inexpensive, scalable and robust, and thus it enables reliable storage of large numbers of low-volume gas samples from remote field locations.

scholarly journals Ozone, Carbon monoxide and Nitrogen oxides time series at four Alpine GAW mountain stations in Central Europe

2010 ◽  
Vol 10 (8) ◽  
pp. 19071-19127 ◽  
Author(s):  
S. Gilge ◽  
C. Plass-Duelmer ◽  
W. Fricke ◽  
A. Kaiser ◽  
L. Ries ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Anthropogenic Impacts ◽  
Vertical Mixing ◽  
Atmospheric Composition ◽  
Altitude Range ◽  
Calibration Laboratory ◽  
Central European ◽  
Mixing Ratios ◽  
Weekly Cycles

Abstract. Long-term, ground based in-situ observations of Ozone (O3) and its precursor gases Nitrogen dioxide (NO2) and Carbon monoxide (CO) from the four sites Hohenpeissenberg and Zugspitze (D), Sonnblick (A) and Jungfraujoch (CH) are presented for the period 1995–2007. These Central European alpine mountain observatories cover an altitude range of roughly 1000 to 3500 m. Comparable analytical methods and common quality assurance (QA) procedures are used at all sites. For O3 and CO, calibration is linked to primary calibrations (O3) or CO standards provided by the Central Calibration Laboratory (CCL) at NOAA/ESRL. All stations have been audited by the World Calibration Centre (WCC) for CO and O3 (WCC-Empa; CH). Data from long-term measurements of NO2 and CO are only available from Hohenpeissenberg and Jungfraujoch. Both sites show slightly decreasing mixing ratios of the primarily emitted NO2 and the partly anthropogenically emitted CO between 1995 and 2007. The findings are generally consistent with shorter observation periods at Zugspitze and Sonnblick and thus are considered to represent regional changes in Central European atmospheric composition at this altitude range. Over the same period 1995–2007, the O3 mixing ratios have slightly increased at three of the four sites. This was observed independent of wind sector and for most seasons, with a tendency to higher positive trends in winter and lower and partly negative trends in summer. Trends are often more pronounced in winter and less in summer; highest declines of NO2 and CO are observed in winter and the lowest in summer, whereas the highest rate of O3 increase was detected in winter and lowest in summer, respectively. Weekly cycles demonstrate anthropogenic impact at all elevations with enhanced NO2 on working days compared to weekends. Enhanced O3 values on working days indicating photochemical production from anthropogenic precursors are only observed in summer, whereas in all other seasons anti-correlation with NO2, was found due to reduced O3 values on working days. Trends are discussed with respect to anthropogenic impacts and vertical mixing. The observed trends for NO2 at the alpine mountain sites are less pronounced than trends estimated based on emission inventories.

scholarly journals Regional variability in black carbon and carbon monoxide ratio from long-term observations over East Asia: assessment of representativeness for black carbon (BC) and carbon monoxide (CO) emission inventories

2020 ◽  
Vol 20 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Yongjoo Choi ◽  
Yugo Kanaya ◽  
Seung-Myung Park ◽  
Atsushi Matsuki ◽  
Yasuhiro Sadanaga ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
South Korea ◽  
East Asia ◽  
Black Carbon ◽  
North Korea ◽  
Northeast China ◽  
Emission Inventory ◽  
East China ◽  
Co Emission

Abstract. The black carbon (BC) and carbon monoxide (CO) emission ratios were estimated and compiled from long-term, harmonized observations of the ΔBC∕ΔCO ratios under conditions unaffected by wet deposition at four sites in East Asia, including two sites in South Korea (Baengnyeong and Gosan) and two sites in Japan (Noto and Fukuoka). Extended spatio-temporal coverage enabled estimation of the full seasonality and elucidation of the emission ratio in North Korea for the first time. The estimated ratios were used to validate the Regional Emission inventory in ASia (REAS) version 2.1 based on six study domains (“East China”, “North China”, “Northeast China”, South Korea, North Korea, and Japan). We found that the ΔBC∕ΔCO ratios from four sites converged into a narrow range (6.2–7.9 ng m−3 ppb−1), suggesting consistency in the results from independent observations and similarity in source profiles over the regions. The BC∕CO ratios from the REAS emission inventory (7.7 ng m−3 ppb−1 for East China – 23.2 ng m−3 ppb−1 for South Korea) were overestimated by factors of 1.1 for East China to 3.0 for South Korea, whereas the ratio for North Korea (3.7 ng m−3 ppb−1 from REAS) was underestimated by a factor of 2.0, most likely due to inaccurate emissions from the road transportation sector. Seasonal variation in the BC∕CO ratio from REAS was found to be the highest in winter (China and North Korea) or summer (South Korea and Japan), whereas the measured ΔBC∕ΔCO ratio was the highest in spring in all source regions, indicating the need for further characterization of the seasonality when creating a bottom-up emission inventory. At levels of administrative districts, overestimation in Seoul, the southwestern regions of South Korea, and Northeast China was noticeable, and underestimation was mainly observed in the western regions in North Korea, including Pyongyang. These diagnoses are useful for identifying regions where revisions in the inventory are necessary, providing guidance for the refinement of BC and CO emission rate estimates over East Asia.

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