scholarly journals Six years of high-precision quasi-continuous atmospheric greenhouse gas measurements at Trainou Tower (Orléans Forest, France)

2014 ◽  
Vol 7 (1) ◽  
pp. 569-604 ◽  
Author(s):  
M. Schmidt ◽  
M. Lopez ◽  
C. Yver Kwok ◽  
C. Messager ◽  
M. Ramonet ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Atmospheric Measurements ◽  
Short Term ◽  
Gas Detector ◽  
Sampling Height ◽  
The Mean ◽  
Drying System ◽  
Gas Measurements ◽  
Television Tower

Abstract. Results from the Trainou tall tower measurement station installed in 2006, are presented for atmospheric measurements of CO2, CH4, N2O, SF6, CO, H2 mole fractions and Radon-222 activity. Air is sampled from four sampling heights (180 m, 100 m, 50 m and 5 m) of the Trainou 200 m television tower in the Orléans forest in France (47°57'53'' N, 2°06'45'' E, 131 m a.s.l.). The station is equipped with a custom-build CO2 analyzer (CARIBOU), which is based on a commercial NDIR analyser (Licor 6252), and a coupled gas chromatographic GC system equipped with ECD and FID (HP6890N, Agilent) and a reduction gas detector (PP1, Peak Performer). Air intakes, pumping and air drying system are shared between the CARIBOU and the GC systems. After some initial problems, we achieved short-term repeatability (1 sigma, over several days) for the GC system of of 0.05 ppm for CO2, 1.4 ppb for CH4, 0.25 ppb for N2O, 0.08 ppb for SF6, 0.88 ppb for CO and 3.8 for H2. The repeatability of the CARIBOU CO2 analyser is 0.06 ppm. In addition to the in-situ measurements, weekly flask sampling is performed, and flask air samples are analysed at the LSCE central laboratory for the same species as well for stable isotopes of CO2. The comparison between in-situ measurements and the flask sampling showed averaged differences of 0.08 ± 1.4 ppm CO2, 0.69 ± 7.3 ppb CH4, 0.64 ± 0.62 ppb N2O, 0.01 ± 0.1 ppt SF6 and 1.5 ± 5.3 ppb CO for the years 2008–2012. At Trainou station, the mean annual increase rates from 2007 to 2011 at the 180 m sampling height were 2.2 ppm yr−1 for CO2, 4 ppb yr−1 for CH4, 0.78 ppb yr−1 for N2O and 0.29 ppt yr−1 for SF6 respectively. For all species the 180 m sampling level showed the smallest diurnal variation. Mean diurnal gradients between the 50 m and the 180 m sampling level reached up to 30 ppm CO2, 15 ppm CH4 or 0.5 ppb N2O during night whereas the mean gradients are smaller than 0.5 ppm for CO2 and 1.5 ppb for CH4 during afternoon.

scholarly journals High-precision quasi-continuous atmospheric greenhouse gas measurements at Trainou tower (Orléans forest, France)

2014 ◽  
Vol 7 (7) ◽  
pp. 2283-2296 ◽  
Author(s):  
M. Schmidt ◽  
M. Lopez ◽  
C. Yver Kwok ◽  
C. Messager ◽  
M. Ramonet ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Atmospheric Measurements ◽  
Flame Ionization ◽  
Gas Detector ◽  
Sampling Height ◽  
The Mean ◽  
Drying System ◽  
Gas Measurements ◽  
Television Tower

Abstract. Results from the Trainou tall tower measurement station installed in 2006 are presented for atmospheric measurements of CO2, CH4, N2O, SF6, CO, H2 mole fractions and radon-222 activity. Air is sampled from four sampling heights (180, 100, 50 and 5 m) of the Trainou 200 m television tower in the Orléans forest in France (47°57'53" N, 2°06'45" E, 131 m a.s.l.). The station is equipped with a custom-built CO2 analyser (CARIBOU), which is based on a commercial non-dispersive, infrared (NDIR) analyser (Licor 6252), and a coupled gas chromatography (GC) system equipped with an electron capture detector (ECD) and a flame ionization detector (FID) (HP6890N, Agilent) and a reduction gas detector (PP1, Peak Performer). Air intakes, pumping and air drying system are shared between the CARIBOU and the GC systems. The ultimately achieved short-term repeatability (1 sigma, over several days) for the GC system is 0.05 ppm for CO2, 1.4 ppb for CH4, 0.25 ppb for N2O, 0.08 ppb for SF6, 0.88 ppb for CO and 3.8 for H2. The repeatability of the CARIBOU CO2 analyser is 0.06 ppm. In addition to the in situ measurements, weekly flask sampling is performed, and flask air samples are analysed at the Laboratoire des Sciences du Climat et de l'Environnement (LSCE) central laboratory for the same species as well for stable isotopes of CO2. The comparison between in situ measurements and the flask sampling showed averaged differences of 0.08 ± 1.40 ppm for CO2, 0.7 ± 7.3 ppb for CH4, 0.6 ± 0.6 ppb for N2O, 0.01 ± 0.10 ppt for SF6, 1.5± 5.3 ppb for CO and 4.8± 6.9 ppb for H2 for the years 2008–2012. At Trainou station, the mean annual increase rates from 2007 to 2011 at the 180 m sampling height were 2.2 ppm yr−1 for CO2, 4 ppb yr−1 for CH4, 0.78 ppb yr−1 for N2O and 0.29 ppt yr−1 for SF6. For all species, the 180 m sampling level showed the smallest diurnal variation. Mean diurnal gradients between the 50 m and the 180 m sampling level reached up to 30 ppm CO2, 15 ppm CH4 or 0.5 ppb N2O during nighttime whereas the mean gradients are smaller than 0.5 ppm for CO2 and 1.5 ppb for CH4 during afternoon.

scholarly journals Short-term variation in atmospheric constituents associated with local front passage observed by a 3-D coherent Doppler lidar and in-situ aerosol/gas measurements

2019 ◽  
Vol 3 ◽  
pp. 100043
Author(s):  
Hisahiro Takashima ◽  
Keiichiro Hara ◽  
Chiharu Nishita-Hara ◽  
Yasushi Fujiyoshi ◽  
Koichi Shiraishi ◽  
...  
Keyword(s):  
Doppler Lidar ◽  
Short Term ◽  
Coherent Doppler Lidar ◽  
Term Variation ◽  
Gas Measurements

Nitrogen Fixation and Phosphorus Turnover in a Hypertrophic Prairie Lake

1983 ◽  
Vol 40 (11) ◽  
pp. 1853-1860 ◽  
Author(s):  
B. G. Brownlee ◽  
T. P. Murphy
Keyword(s):  
Nitrogen Fixation ◽  
Light Intensity ◽  
Acetylene Reduction ◽  
Ammonia Volatilization ◽  
Molar Ratio ◽  
Short Term ◽  
Nitrogen Reduction ◽  
The Mean ◽  
Phosphorus Turnover

Nitrogen fixation by Aphanizomenon flos-aquae in a prairie lake in southwestern Manitoba was dependent on the light intensity and in situ oxygen concentrations. The mean molar ratio of acetylene reduction to nitrogen reduction was 5.8:1. High external ammonium concentrations did not appear to inhibit nitrogen fixation over the short term. Nitrogen fixation was not directly initiated by the bloom collapse. We propose that the coupled sequence of ammonia volatilization and nitrogen fixation was triggered by the bloom collapse and that the bloom collapse was caused by coprecipitation of orthophosphate with carbonates. 32PO4 turnover was most rapid during periods when the lake was opalescent, presumably due to carbonate precipitaton.

scholarly journals A statistical approach to quantify uncertainty in carbon monoxide measurements at the Izaña global GAW station: 2008–2011

2012 ◽  
Vol 5 (5) ◽  
pp. 6949-6989 ◽  
Author(s):  
A. J. Gomez-Pelaez ◽  
R. Ramos ◽  
V. Gomez-Trueba ◽  
P. C. Novelli ◽  
R. Campo-Hernandez
Keyword(s):  
Carbon Monoxide ◽  
Response Function ◽  
Measurement System ◽  
Minimum Variance ◽  
Standard Uncertainty ◽  
In Situ Measurements ◽  
North East ◽  
The Mean ◽  
Mean Differences

Abstract. Atmospheric CO in-situ measurements are carried out at the Izaña (Tenerife) global GAW mountain station using a RGA (Reduction Gas Analyser). In-situ measurements at Izaña are representative of the subtropical North-East Atlantic free troposphere, specially during the night period. We present the measurement system configuration, the response function, the calibration scheme, the data processing, the Izaña's 2008–2011 CO nocturnal time series, and the mean diurnal cycle by months. We have developed a rigorous uncertainty analysis for carbon monoxide measurements carried out at the Izaña station which could be applied to other GAW stations. We determine the combined standard uncertainty from four components of the measurement: uncertainty of the WMO standard gases interpolated over the range of measurement, the uncertainty that takes into account the agreement between the standard gases and the response function used, the uncertainty due to the repeatability of the injections, and the propagated uncertainty related to the response function parameters uncertainties (which also takes into account the covariance between the parameters). The mean value of the combined standard uncertainty decreased significantly after March 2009, from 2.37 nmol mol−1 to 1.66 nmol mol−1, due to improvements in the measurement system. A fifth type of uncertainty we call representation uncertainty is considered when some of the data necessary to compute exactly the mean are absent. Any computed mean has also a propagated uncertainty arising from the uncertainties of the data used to compute the mean. The law of propagation depends on the type of uncertainty component (random or systematic). In-situ hourly means are compared with simultaneous and collocated NOAA flask samples. The uncertainty in the differences is determined and whether these are significant. For 2009–2011, only 24.5% of the differences are significant, and 68% of the differences are between −2.39 and 2.5 nmol mol−1. Total and annual mean differences are computed using conventional expressions but also expressions with weights based on the minimum variance method. The annual mean differences for 2009–2011 are well within the ±2 nmol mol−1 compatibility goal of GAW.

scholarly journals In-situ measurements of atmospheric hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) at the Shangdianzi regional background station, China

2012 ◽  
Vol 12 (5) ◽  
pp. 11151-11173
Author(s):  
B. Yao ◽  
M. K. Vollmer ◽  
L. X. Zhou ◽  
S. Henne ◽  
S. Reimann ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Ratio Method ◽  
High Concentration ◽  
Urban Sector ◽  
Mixing Ratios ◽  
Regional Background ◽  
Hfc 134A ◽  
The Mean ◽  
Measurement Period

Abstract. In-situ measurements of atmospheric hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) have been conducted at the Shangdianzi (SDZ) Global Atmosphere Watch (GAW) regional background station, China, from May 2010 to May 2011. The time series for 5 HFCs and 4 PFCs periodically showed high concentration events while background conditions occurred for 36% (HFC-32) to 83% (PFC-218) of all measurements. The mean mixing ratios during background conditions for HFC-23, HFC-32, HFC-125, HFC-134a, HFC-152, CF4, PFC-116, PFC-218 and PFC-318 were 24.5, 5.86, 9.97, 66.0, 9.77, 79.1, 4.22, 0.56, 1.28 ppt (parts per trillion, 10−12, molar), respectively. The background mixing ratios for the compounds at SDZ are consistent with those obtained at mid to high latitude sites in the Northern Hemisphere, except for HFC-32 and PFC-318 for which background mixing ratios were not reported in recent years. All HFCs and PFCs show positive trends at rates of 0.7, 1.4, 1.6, 4.1, 1.1, 0.43, 0.05, 0.01, 0.04 ppt yr−1 for HFC-23, HFC-32, HFC-125, HFC-134a, HFC-152, CF4, PFC-116, PFC-218 and PFC-318, respectively. North-easterly winds were connected with small contributions to atmospheric HFCs and PFCs loadings, whereas south-westerly advection (urban sector) showed increased loadings. Chinese emissions were estimated by a tracer ratio method using CO as tracer with rather well known emissions. The emissions, as derived from our measurement period, were 4.4 ± 0.7, 6.9 ± 0.9, 2.5 ± 0.3, 9.0 ± 1.3, 2.2 ± 0.4, 2.1 ± 0.3, 0.24 ± 0.06, 0.07 ± 0.04, 0.45 ± 0.09 kt yr−1 for HFC-23, HFC-32, HFC-125, HFC-134a, HFC-152, CF4, PFC-116, PFC-218, and PFC-318, respectively. The lower HFC-23 emissions compared to earlier studies may be a result of the HFC-23 abatement measures taken as part of the Clean Development Mechanism (CDM) project that started in 2005.

scholarly journals Maïdo observatory: a new high-altitude station facility at Reunion Island (21° S, 55° E) for long-term atmospheric remote sensing and in situ measurements

2013 ◽  
Vol 6 (10) ◽  
pp. 2865-2877 ◽  
Author(s):  
J.-L. Baray ◽  
Y. Courcoux ◽  
P. Keckhut ◽  
T. Portafaix ◽  
P. Tulet ◽  
...  
Keyword(s):  
High Altitude ◽  
Southern Hemisphere ◽  
Marine Boundary Layer ◽  
In Situ Measurements ◽  
Atmospheric Composition ◽  
Reunion Island ◽  
Atmospheric Measurements ◽  
Atmospheric Remote Sensing ◽  
Réunion Island

Abstract. Since the nineties, atmospheric measurement systems have been deployed at Reunion Island, mainly for monitoring the atmospheric composition in the framework of NDSC/NDACC (Network for the Detection of Stratospheric Change/Network for the Detection of Atmospheric Composition Change). The location of Reunion Island presents a great interest because there are very few multi-instrumented stations in the tropics and particularly in the southern hemisphere. In 2012, a new observatory was commissioned in Maïdo at 2200 m above sea level: it hosts various instruments for atmospheric measurements, including lidar systems, spectro-radiometers and in situ gas and aerosol measurements. This new high-altitude Maïdo station provides an opportunity: 1. to improve the performance of the optical instruments above the marine boundary layer, and to open new perspectives on upper troposphere and lower stratosphere studies; 2. to develop in situ measurements of the atmospheric composition for climate change surveys, in a reference site in the tropical/subtropical region of the southern hemisphere; 3. to offer trans-national access to host experiments or measurement campaigns for focused process studies.

scholarly journals Evaluation of the Lidar–Radar Cloud Ice Water Content Retrievals Using Collocated in Situ Measurements

2015 ◽  
Vol 54 (10) ◽  
pp. 2087-2097 ◽  
Author(s):  
Sujan Khanal ◽  
Zhien Wang
Keyword(s):  
Remote Sensing ◽  
Water Content ◽  
Cloud Microphysics ◽  
In Situ Measurements ◽  
Ice Water Content ◽  
Flight Level ◽  
The Mean ◽  
Cloud Ice ◽  
Ice Water

AbstractRemote sensing and in situ measurements made during the Colorado Airborne Multiphase Cloud Study, 2010–2011 (CAMPS) with instruments aboard the University of Wyoming King Air aircraft are used to evaluate lidar–radar-retrieved cloud ice water content (IWC). The collocated remote sensing and in situ measurements provide a unique dataset for evaluation studies. Near-flight-level IWC retrieval is compared with an in situ probe: the Colorado closed-path tunable diode laser hygrometer (CLH). Statistical analysis showed that the mean radar–lidar IWC is within 26% of the mean in situ measurements for pure ice clouds and within 9% for liquid-topped mixed-phase clouds. Considering their different measurement techniques and different sample volumes, the comparison shows a statistically good agreement and is close to the measurement uncertainty of the CLH, which is around 20%. It is shown that ice cloud microphysics including ice crystal shape and orientation has a significant impact on IWC retrievals. These results indicate that the vertical profile of the retrieved lidar–radar IWC can be reliably combined with the flight-level measurements made by the in situ probes to provide a more complete picture of the cloud microphysics.

scholarly journals More evidence for very short-lived substance contribution to stratospheric chlorine inferred from HCl balloon-borne in situ measurements in the tropics

2010 ◽  
Vol 10 (2) ◽  
pp. 397-409 ◽  
Author(s):  
Y. Mébarki ◽  
V. Catoire ◽  
N. Huret ◽  
G. Berthet ◽  
C. Robert ◽  
...  
Keyword(s):  
In Situ Measurements ◽  
Tunable Diode Laser ◽  
Vertical Profiles ◽  
Tropical Tropopause Layer ◽  
Laser Absorption ◽  
Tropical Tropopause ◽  
Product Gas ◽  
Gas Measurements ◽  
The Tropics

Abstract. Volume mixing ratio (vmr) vertical profiles of hydrogen chloride (HCl) are retrieved from in situ measurements performed by a balloon-borne infrared tunable diode laser absorption spectrometer (SPIRALE) during two balloon flights in the tropics (Teresina, Brazil, 5.1° S–42.9° W) in June 2005 and June 2008. HCl vertical profiles obtained from 15 to 31 km are presented and analysed to estimate the contribution of very short-lived substances (VSLS) to total stratospheric chlorine. Both retrieved vertical profiles of HCl from these flights agree very well with each other, with estimated overall uncertainties of 6% on vmr between 23 and 31 km. Upper limits of HCl vmr as low as 20 pptv in June 2008 and 30 pptv in June 2005 are inferred in the upper part of the tropical tropopause layer (TTL). Backward trajectory calculations and such low amounts suggest that the air masses sampled correspond to typical background conditions, i.e. neither influenced by recent tropospheric nor stratospheric air. Taking into account the recently reported VSL source gas measurements obtained in similar conditions (Laube et al., 2008) and the main intermediate degradation product gas COCl2 (Fu et al., 2007), a total VSLS contribution of 85±40 pptv to stratospheric chlorine is inferred. This refines the WMO (2007) estimation of 50 to 100 pptv, which was not taking into account any HCl contribution. In addition, comparisons of HCl measurements between SPIRALE and the Aura MLS satellite instrument in the tropical lower and middle stratosphere lead to a very good agreement. The previous agreement between MLS-deduced upper stratospheric total chlorine content and modelled values including 100 pptv of VSLS (Froidevaux et al., 2006) is thus supported by our present result about the VSLS contribution.

scholarly journals In situ measurements of molecular iodine in the marine boundary layer: the link to macroalgae and the implications for O<sub>3</sub>, IO, OIO and NO<sub>x</sub>

2010 ◽  
Vol 10 (10) ◽  
pp. 4823-4833 ◽  
Author(s):  
R.-J. Huang ◽  
K. Seitz ◽  
J. Buxmann ◽  
D. Pöhler ◽  
K. E. Hornsby ◽  
...  
Keyword(s):  
Marine Boundary Layer ◽  
Algal Species ◽  
Molecular Iodine ◽  
In Situ Measurements ◽  
Gas Chromatography Mass Spectrometry ◽  
Optical Absorption Spectroscopy ◽  
Atmospheric Measurements ◽  
Mixing Ratios ◽  
Inorganic Iodine

Abstract. Discrete in situ atmospheric measurements of molecular iodine (I2) were carried out at Mace Head and Mweenish Bay on the west coast of Ireland using diffusion denuders in combination with a gas chromatography-mass spectrometry (GC-MS) method. I2, IO and OIO were also measured by long-path differential optical absorption spectroscopy (LP-DOAS). The simultaneous denuder and LP-DOAS I2 measurements were well correlated (R2=0.80) but the denuder method recorded much higher concentrations. This can be attributed to the fact that the in situ measurements were made near to macroalgal sources of I2 in the intertidal zone, whereas the LP-DOAS technique provides distance-averaged mixing ratios of an inhomogeneous distribution along the light-path. The observed mixing ratios of I2 at Mweenish Bay were significantly higher than that at Mace Head, which is consistent with differences in local algal biomass density and algal species composition. Above algal beds, levels of I2 were found to correlate inversely with tidal height and positively with the concentrations of O3 in the surrounding air, indicating a role for O3 in the production of I2 from macroalgae, as has been previously suggested from laboratory studies. However, measurements made ~150 m away from the algal beds showed a negative correlation between O3 and I2 during both day and night. We interpret these results to indicate that the released I2 can also lead to O3 destruction via the reaction of O3 with I atoms that are formed by the photolysis of I2 during the day and via the reaction of I2 with NO3 radicals at night. The results show that the concentrations of daytime IO are correlated with the mixing ratios of I2, and suggest that the local algae sources dominate the inorganic iodine chemistry at Mace Head and Mweenish Bay.

scholarly journals A statistical approach to quantify uncertainty in carbon monoxide measurements at the Izaña global GAW station: 2008–2011

2013 ◽  
Vol 6 (3) ◽  
pp. 787-799 ◽  
Author(s):  
A. J. Gomez-Pelaez ◽  
R. Ramos ◽  
V. Gomez-Trueba ◽  
P. C. Novelli ◽  
R. Campo-Hernandez
Keyword(s):  
Carbon Monoxide ◽  
Response Function ◽  
Measurement System ◽  
Minimum Variance ◽  
Standard Uncertainty ◽  
In Situ Measurements ◽  
Temporal Consistency ◽  
The Mean ◽  
Mean Differences

Abstract. Atmospheric CO in situ measurements are carried out at the Izaña (Tenerife) global GAW (Global Atmosphere Watch Programme of the World Meteorological Organization – WMO) mountain station using a Reduction Gas Analyser (RGA). In situ measurements at Izaña are representative of the subtropical Northeast Atlantic free troposphere, especially during nighttime. We present the measurement system configuration, the response function, the calibration scheme, the data processing, the Izaña 2008–2011 CO nocturnal time series, and the mean diurnal cycle by months. We have developed a rigorous uncertainty analysis for carbon monoxide measurements carried out at the Izaña station, which could be applied to other GAW stations. We determine the combined standard measurement uncertainty taking into consideration four contributing components: uncertainty of the WMO standard gases interpolated over the range of measurement, the uncertainty that takes into account the agreement between the standard gases and the response function used, the uncertainty due to the repeatability of the injections, and the propagated uncertainty related to the temporal consistency of the response function parameters (which also takes into account the covariance between the parameters). The mean value of the combined standard uncertainty decreased significantly after March 2009, from 2.37 nmol mol−1 to 1.66 nmol mol−1, due to improvements in the measurement system. A fifth type of uncertainty we call representation uncertainty is considered when some of the data necessary to compute the temporal mean are absent. Any computed mean has also a propagated uncertainty arising from the uncertainties of the data used to compute the mean. The law of propagation depends on the type of uncertainty component (random or systematic). In situ hourly means are compared with simultaneous and collocated NOAA flask samples. The uncertainty of the differences is computed and used to determine whether the differences are significant. For 2009–2011, only 24.5% of the differences are significant, and 68% of the differences are between −2.39 and 2.5 nmol mol−1. Total and annual mean differences are computed using conventional expressions but also expressions with weights based on the minimum variance method. The annual mean differences for 2009–2011 are well within the &amp;pm;2 nmol mol−1 compatibility goal of GAW.

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