scholarly journals Continuous CO<sub>2</sub>/CH<sub>4</sub>/CO measurements (2012-2014) at Beromünster tall tower station in Switzerland

2016 ◽  
Author(s):  
E. Satar ◽  
T. A. Berhanu ◽  
D. Brunner ◽  
S. Henne ◽  
M. Leuenberger
Keyword(s):  
Regional Scale ◽  
Vertical Mixing ◽  
Monitoring Network ◽  
Ground Level ◽  
Diurnal Variations ◽  
Future Climate Change ◽  
Mixing Ratios ◽  
Seasonal And Diurnal Variations ◽  
Flux Measurements ◽  
Storage Flux

Abstract. The understanding of the continental carbon budget is essential to predict future climate change. In order to quantify CO2 and CH4 fluxes at the regional scale, a measurement system was installed at the former radio tower in Beromünster as a part of the Swiss greenhouse gas monitoring network (CarboCount CH). We have been measuring the mixing ratios of CO2, CH4 and CO on this tower with sample inlets at 12.5, 44.6, 71.5, 131.6 and 212.5 m above ground level using a cavity ring down spectroscopy (CRDS) analyzer. The first two-year (December 2012-December 2014) continuous atmospheric record was analyzed for seasonal and diurnal variations and inter-species correlations. In addition, storage fluxes were calculated from the hourly profiles along the tower. The atmospheric growth rates from 2013 to 2014 determined from this two-year dataset were 1.78 ppm yr-1, 9.66 ppb yr-1 and -1.27 ppb yr-1 for CO2, CH4 and CO, respectively. After detrending, clear seasonal cycles were detected for CO2 and CO, whereas CH4 showed a stable baseline suggesting a net balance between sources and sinks over the course of the year. CO and CO2 were strongly correlated (r2 > 0.75) in winter (DJF), but almost uncorrelated in summer. In winter, anthropogenic emissions dominate the biospheric CO2 fluxes and the variations in mixing ratios are large due to reduced vertical mixing. The diurnal variations of all species showed distinct cycles in spring and summer, with the lo west sampling level showing the most pronounced diurnal amplitudes. The storage flux estimates exhibited reasonable diurnal shapes for CO2, but underestimated the strength of the surface sinks during daytime. This seems plausible, keeping in mind that we were only able to calculate the storage fluxes along the profile of the tower but not the flux into or out of this profile, since no Eddy covariance flux measurements were taken at the top of the tower.

scholarly journals Continuous CO<sub>2</sub>/CH<sub>4</sub>/CO measurements (2012–2014) at Beromünster tall tower station in Switzerland

2016 ◽  
Vol 13 (9) ◽  
pp. 2623-2635 ◽  
Author(s):  
Ece Satar ◽  
Tesfaye A. Berhanu ◽  
Dominik Brunner ◽  
Stephan Henne ◽  
Markus Leuenberger
Keyword(s):  
Regional Scale ◽  
Vertical Mixing ◽  
Monitoring Network ◽  
Ground Level ◽  
Diurnal Variations ◽  
Future Climate Change ◽  
Data Set ◽  
Mixing Ratios ◽  
Seasonal And Diurnal Variations ◽  
Storage Flux

Abstract. The understanding of the continental carbon budget is essential to predict future climate change. In order to quantify CO2 and CH4 fluxes at the regional scale, a measurement system was installed at the former radio tower in Beromünster as part of the Swiss greenhouse gas monitoring network (CarboCount CH). We have been measuring the mixing ratios of CO2, CH4 and CO on this tower with sample inlets at 12.5, 44.6, 71.5, 131.6 and 212.5 m above ground level using a cavity ring down spectroscopy (CRDS) analyzer. The first 2-year (December 2012–December 2014) continuous atmospheric record was analyzed for seasonal and diurnal variations and inter-species correlations. In addition, storage fluxes were calculated from the hourly profiles along the tower. The atmospheric growth rates from 2013 to 2014 determined from this 2-year data set were 1.78 ppm yr−1, 9.66 ppb yr−1 and −1.27 ppb yr−1 for CO2, CH4 and CO, respectively. After detrending, clear seasonal cycles were detected for CO2 and CO, whereas CH4 showed a stable baseline suggesting a net balance between sources and sinks over the course of the year. CO and CO2 were strongly correlated (r2 > 0.75) in winter (DJF), but almost uncorrelated in summer. In winter, anthropogenic emissions dominate the biospheric CO2 fluxes and the variations in mixing ratios are large due to reduced vertical mixing. The diurnal variations of all species showed distinct cycles in spring and summer, with the lowest sampling level showing the most pronounced diurnal amplitudes. The storage flux estimates exhibited reasonable diurnal shapes for CO2, but underestimated the strength of the surface sinks during daytime. This seems plausible, keeping in mind that we were only able to calculate the storage fluxes along the profile of the tower but not the flux into or out of this profile, since no Eddy covariance flux measurements were taken at the top of the tower.

scholarly journals Seasonal and Diurnal Variations of Ozone near the Mesopause from Observations of the 11.072-GHz Line

2009 ◽  
Vol 26 (10) ◽  
pp. 2192-2199 ◽  
Author(s):  
A. E. E. Rogers ◽  
M. Lekberg ◽  
P. Pratap
Keyword(s):  
Seasonal Variation ◽  
Seasonal Variations ◽  
Atomic Hydrogen ◽  
Diurnal Variations ◽  
Mixing Ratio ◽  
Mesopause Region ◽  
Mixing Ratios ◽  
Rates Of Change ◽  
Broadband Emission ◽  
Seasonal And Diurnal Variations

Abstract Ground-based observations of the 11.072-GHz line of ozone were made from January 2008 through January 2009. These observations provide an estimate of the diurnal and seasonal variations of ozone in the mesopause region. The 11-GHz line is more sensitive to the ozone at higher altitudes than ground observations of the 142-GHz line, because of the reduced Doppler line width. The observations show an increase in the volume mixing ratio of ozone above 80 km at night by more than a factor of 10 and a seasonal variation of about a factor of 2, which is consistent with the semiannual variations of atomic hydrogen in the mesopause region. The diurnal amplitude and rates of change of the mixing ratios at sunrise and sunset are compared with ground-based observations of the 142-GHz line and the observations of the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) satellite, as well as with a simplified chemical model of the creation and destruction of ozone in the mesopause region.

scholarly journals Sesquiterpenes identified as key species for atmospheric chemistry in boreal forest by terpenoid and OVOC measurements

2018 ◽  
Author(s):  
Heidi Hellén ◽  
Arnaud P. Praplan ◽  
Toni Tykkä ◽  
Ilona Ylivinkka ◽  
Ville Vakkari ◽  
...  
Keyword(s):  
Organic Acids ◽  
Boreal Forest ◽  
Atmospheric Chemistry ◽  
Vertical Mixing ◽  
Diurnal Variations ◽  
Oxidation Products ◽  
Key Species ◽  
Seasonal And Diurnal Variations ◽  
Volatile Organic ◽  
Volatile Organic Acids

Abstract. Concentrations of terpenoids (isoprene, monoterpenes, sesquiterpenes) and oxygenated volatile organic compounds (OVOCs, i.e. aldehydes, alcohols, acetates and volatile organic acids) were investigated during two years at a boreal forest site in Hyytiälä, Finland, using in situ gas chromatograph-mass spectrometers (GC-MS). Seasonal and diurnal variations of terpenoid and OVOC concentrations as well as their relationship with meteorological factors were studied. Of the studied VOCs, C2-C7 unbranched volatile organic acids (VOAs) were found to have the highest concentrations mainly due to their low reactivity. Of the terpenoids, monoterpenes (MTs) had highest concentrations at the site, but also 7 different highly reactive sesquiterpenes (SQTs) were detected. Monthly and daily mean concentrations of most terpenoids, aldehydes and VOAs were found to be highly dependent on the temperature. Highest exponential correlation with temperature was found for a SQT (β-caryophyllene) in summer. The diurnal variations of the concentrations could be explained by sources, sinks and vertical mixing. Especially the diurnal variations of MT concentrations were strongly affected by vertical mixing. Based on the temperature correlations and mixing layer height simple proxies were developed for estimating MT and SQT concentrations. To estimate the importance of different compound groups and compounds for the local atmospheric chemistry, reactivity with main oxidants (OH, NO3 and O3) and production rates of oxidation products (OxPR) were calculated. MTs dominated OH and NO3 radical chemistry, but SQTs had a major impact on ozone chemistry, even though concentrations of SQT were 30 times lower than MT concentrations. SQTs were the most important also for the production of oxidation products. Since SQTs have high secondary organic aerosol (SOA) yields, results clearly indicate the importance of SQTs for local SOA production.

scholarly journals Comparative Analysis on the Estimation of Diurnal Solar-Induced Chlorophyll Fluorescence Dynamics for a Subtropical Evergreen Coniferous Forest

2021 ◽  
Vol 13 (16) ◽  
pp. 3143
Author(s):  
Jinghua Chen ◽  
Shaoqiang Wang ◽  
Bin Chen ◽  
Yue Li ◽  
Muhammad Amir ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Temporal Dynamics ◽  
Gross Primary Production ◽  
Stomatal Closure ◽  
Chlorophyll Concentration ◽  
Coniferous Forest ◽  
Diurnal Variations ◽  
Future Climate Change ◽  
Ecosystem Carbon ◽  
Seasonal And Diurnal Variations

Solar-induced chlorophyll fluorescence (SIF) is considered as a prospective indicator of vegetation photosynthetic activity and the ecosystem carbon cycle. The current coarse spatial-temporal resolutions of SIF data from satellite missions and ground measurements still cannot satisfy the corroboration of its correlation with photosynthesis and carbon flux. Practical approaches are needed to be explored for the supplementation of the SIF measurements. In our study, we clarified the diurnal variations of leaf and canopy chlorophyll fluorescence for a subtropical evergreen coniferous forest and evaluated the performance of the canopy chlorophyll concentration (CCC) approach and the backward approach from gross primary production (GPP) for estimating the diurnal variations of canopy SIF by comparing with the Soil Canopy Observation Photosynthesis Energy (SCOPE) model. The results showed that the canopy SIF had similar seasonal and diurnal variations with the incident photosynthetically active radiation (PAR) above the canopy, while the leaf steady-state fluorescence remained stable during the daytime. Neither the CCC nor the raw backward approach from GPP could capture the short temporal dynamics of canopy SIF. However, after improving the backward approach with a correction factor of normalized PAR incident on leaves, the variation of the estimated canopy SIF accounted for more than half of the diurnal variations in the canopy SIF (SIF687: R2 = 0.53, p < 0.001; SIF760: R2 = 0.72, p < 0.001) for the subtropical evergreen coniferous forest without water stress. Drought interfered with the utilization of the improved backward approach because of the decoupling of SIF and GPP due to stomatal closure. This new approach offers new insight into the estimation of diurnal canopy SIF and can help understand the photosynthesis of vegetation for future climate change studies.

scholarly journals Measurements of greenhouse gases and related tracers at Bialystok tall tower station in Poland

2010 ◽  
Vol 3 (2) ◽  
pp. 407-427 ◽  
Author(s):  
M. E. Popa ◽  
M. Gloor ◽  
A. C. Manning ◽  
A. Jordan ◽  
U. Schultz ◽  
...  
Keyword(s):  
Average Rate ◽  
Vertical Mixing ◽  
Warm Season ◽  
In Situ Measurements ◽  
Diurnal Variations ◽  
Max Planck ◽  
Seasonal And Diurnal Variations ◽  
Significant Difference ◽  
Tall Tower

Abstract. Quasi-continuous, in-situ measurements of atmospheric CO2, O2/N2, CH4, CO, N2O, and SF6 have been performed since August 2005 at the tall tower station near Bialystok, in Eastern Poland, from five heights up to 300 m. Besides the in-situ measurements, flask samples are filled approximately weekly and measured at Max-Planck Institute for Biogeochemistry for the same species and, in addition, for H2, Ar/N2 and the stable isotopes 13C and 18O in CO2. The in-situ measurement system was built based on commercially available analysers: a LiCor 7000 for CO2, a Sable Systems "Oxzilla" FC-2 for O2, and an Agilent 6890 gas chromatograph for CH4, CO, N2O and SF6. The system was optimized to run continuously with very little maintenance and to fulfill the precision requirements of the CHIOTTO project. The O2/N2 measurements in particular required special attention in terms of technical setup and quality assurance. The evaluation of the performance after more than three years of operation gave overall satisfactory results, proving that this setup is suitable for long term remote operation with little maintenance. The precision achieved for all species is within or close to the project requirements. The comparison between the in-situ and flask sample results, used to verify the accuracy of the in-situ measurements, showed no significant difference for CO2, O2/N2, CH4 and N2O, and a very small difference for SF6. The same comparison however revealed a statistically significant difference for CO, of about 6.5 ppb, for which the cause could not be fully explained. From more than three years of data, the main features at Bialystok have been characterized in terms of variability, trends, and seasonal and diurnal variations. CO2 and O2/N2 show large short term variability, and large diurnal signals during the warm seasons, which attenuate with the increase of sampling height. The trends calculated from this dataset, over the period August 2005 to December 2008, are 2.02±0.46 ppm/year for CO2 and −23.2±2.5 per meg/year for O2/N2. CH4, CO and N2O show also higher variability at the lower sampling levels, which in the case of CO is strongly seasonal. Diurnal variations in CH4, CO and N2O mole fractions can be observed during the warm season, due to the periodicity of vertical mixing combined with the diurnal cycle of anthropogenic emissions. We calculated increase rates of 10.1±4.4 ppb/year for CH4, (−8.3)±5.3 ppb/year for CO and 0.67±0.08 ppb/year for N2O. SF6 shows only few events, and generally no vertical gradients, which suggests that there are no significant local sources. A weak SF6 seasonal cycle has been detected, which most probably is due to the seasonality of atmospheric circulation. SF6 increased during the time of our measurement at an average rate of 0.29±0.01 ppt/year.

scholarly journals Measurements of greenhouse gases and related tracers at Bialystok tall tower station in Poland

2009 ◽  
Vol 2 (5) ◽  
pp. 2587-2637 ◽  
Author(s):  
M. E. Popa ◽  
M. Gloor ◽  
A. C. Manning ◽  
A. Jordan ◽  
U. Schultz ◽  
...  
Keyword(s):  
Average Rate ◽  
Vertical Mixing ◽  
Warm Season ◽  
In Situ Measurements ◽  
Diurnal Variations ◽  
Max Planck ◽  
Seasonal And Diurnal Variations ◽  
Significant Difference ◽  
Tall Tower

Abstract. Quasi-continuous, in-situ measurements of atmospheric CO2, O2/N2, CH4, CO, N2O, and SF6 have been performed since August 2005 at the tall tower station near Bialystok, in Eastern Poland, from five heights up to 300 m. Besides the in-situ measurements, flask samples are filled approximately weekly and measured at Max-Planck Institute for Biogeochemistry for the same species and, in addition, for H2, Ar/N2 and the stable isotopes 13C and 18O in CO2. The in-situ measurement system was build based on commercially available analysers: a LiCor 7000 for CO2, a Sable Systems "Oxzilla" FC-2 for O2, and an Agilent 6890 gas chromatograph for CH4, CO, N2O and SF6. The system was optimized to run continuously with very little maintenance and to fulfill the precision requirements of the CHIOTTO project. The O2 measurements in particular required special attention in terms of technical setup and quality assurance. The evaluation of the performance after more than three years of operation gave overall satisfactory results, proving that this setup is suitable for long term remote operation with little maintenance. The precision achieved for all species is within or close to the project requirements. The comparison between the in-situ and flask sample results, used to verify the accuracy of the in-situ measurements, showed no significant difference for CO2, O2/N2, CH4 and N2O, and a very small difference for SF6. The same comparison however revealed a statistically significant difference for CO, of about 6.5 ppb, for which the cause could not be fully explained at the moment. From more than three years of data, the main features at Bialystok have been characterized in terms of variability, trends, and seasonal and diurnal variations. CO2 and O2/N2 show large short term variability, and large diurnal signals during the warm seasons, which attenuate with the increase of sampling height. The trends calculated from this dataset, over the period August 2005 to December 2008, are 2.02±0.46 ppm/year for CO2 and −23.2±2.5 per meg/year for O2/N2. CH4, CO and N2O show also higher variability at the lower sampling levels, which in the case of CO is strongly seasonal. Diurnal variations in CH4, CO and N2O mole fractions can be observed during the warm season, due to the periodicity of vertical mixing combined with the diurnal cycle of anthropogenic emissions. We calculated increase rates of 10.1±4.4 ppb/year for CH4, (−8.3)±5.3 ppb/year for CO and 0.67±0.08 ppb/year for N2O. SF6 shows only few events, and generally no vertical gradients, which suggests that there are no significant local sources. A weak SF6 seasonal cycle has been detected, which most probably is due to the seasonality of atmospheric circulation. SF6 increased during the time of our measurement at an average rate of 0.29±0.01 ppt/year.

scholarly journals Measurements of diurnal variations and Eddy Covariance (EC) fluxes of glyoxal in the tropical marine boundary layer: description of the Fast LED-CE-DOAS instrument

2014 ◽  
Vol 7 (6) ◽  
pp. 6245-6285 ◽  
Author(s):  
S. Coburn ◽  
I. Ortega ◽  
R. Thalman ◽  
B. Blomquist ◽  
C. W. Fairall ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Marine Boundary Layer ◽  
Light Emitting Diode ◽  
Chemical Properties ◽  
Diurnal Variations ◽  
Optical Absorption Spectroscopy ◽  
Tropical Ocean ◽  
Mixing Ratios ◽  
Flux Measurements ◽  
Fast Light

Abstract. Here we present first Eddy Covariance (EC) measurements of fluxes of glyoxal, the smallest α-dicarbonyl product of hydrocarbon oxidation, and a precursor for secondary organic aerosol (SOA). The unique physical and chemical properties of glyoxal, i.e., high solubility in water (Henry's Law constant, KH = 4.2 × 105 M atm−1) and short atmospheric lifetime (~2 h at solar noon) make it a unique indicator species for organic carbon oxidation in the marine atmosphere. Previous reports of elevated glyoxal over oceans remain unexplained by atmospheric models. Here we describe a Fast Light Emitting Diode Cavity Enhanced Differential Optical Absorption Spectroscopy (Fast LED-CE-DOAS) instrument to measure diurnal variations and EC fluxes of glyoxal, and inform about its unknown sources. The fast in situ sensor is described, and first results are presented from a cruise deployment over the Eastern tropical Pacific Ocean (20° N to 10° S; 133° W to 85° W) as part of the Tropical Ocean Troposphere Exchange of Reactive Halogens and OVOC (TORERO) field experiment (January to March 2012). The Fast LED-CE-DOAS is a multispectral sensor that selectively and simultaneously measures glyoxal (CHOCHO), nitrogen dioxide (NO2), oxygen dimers (O4) and water vapor (H2O) with ~2 Hz time resolution, and a precision of ~40 pptv Hz−0.5 for glyoxal. The instrument is demonstrated to be a "white-noise" sensor suitable for EC flux measurements; further, highly sensitive and inherently calibrated glyoxal measurements are obtained from temporal averaging of data (~2 pptv detection limit over 1 h). The campaign averaged mixing ratio in the Southern Hemisphere (SH) is found to be 43 ± 9 pptv glyoxal, and is higher than in the Northern Hemisphere (NH: 32 ± 6 pptv; error reflects variability over multiple days). The diurnal variation of glyoxal in the MBL is measured for the first time, and mixing ratios vary by ~8 ppt (NH) and ~12 pptv (SH) over the course of 24 h. Consistently, maxima are observed at sunrise (NH: 35 ± 5 pptv; SH: 47 ± 7 pptv) and minima at dusk (NH: 27 ± 5 pptv; SH: 35 ± 8 pptv). Ours are the first EC flux measurements of glyoxal. In both hemispheres, the daytime flux was directed from the atmosphere into the ocean, indicating that the ocean is a net sink for glyoxal during the day. After sunset the ocean was a source for glyoxal to the atmosphere (positive flux) in the SH; this primary ocean source was operative throughout the night. In the NH, the nighttime flux was positive only shortly after sunset, and negative during most of the night. Positive EC fluxes of soluble glyoxal over oceans indicate the presence of an ocean surface organic microlayer (SML), and locate a glyoxal source within the SML. The origin of atmospheric glyoxal, and possibly other oxygenated hydrocarbons over tropical oceans warrants further investigation.

scholarly journals Long-term measurements of volatile organic compounds highlight the importance of sesquiterpenes for the atmospheric chemistry of a boreal forest

2018 ◽  
Vol 18 (19) ◽  
pp. 13839-13863 ◽  
Author(s):  
Heidi Hellén ◽  
Arnaud P. Praplan ◽  
Toni Tykkä ◽  
Ilona Ylivinkka ◽  
Ville Vakkari ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Boreal Forest ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Vertical Mixing ◽  
Diurnal Variations ◽  
Oxidation Products ◽  
Forest Site ◽  
Seasonal And Diurnal Variations ◽  
Volatile Organic

Abstract. The concentrations of terpenoids (isoprene; monoterpenes, MTs; and sesquiterpenes, SQTs) and oxygenated volatile organic compounds (OVOCs; i.e. aldehydes, alcohols, acetates and volatile organic acids, VOAs) were investigated during 2 years at a boreal forest site in Hyytiälä, Finland, using in situ gas chromatograph mass spectrometers (GC-MSs). Seasonal and diurnal variations of terpenoid and OVOC concentrations as well as their relationship with meteorological factors were studied. Of the VOCs examined, C2–C7 unbranched VOAs showed the highest concentrations, mainly due to their low reactivity. Of the terpenoids, MTs showed the highest concentrations at the site, but seven different highly reactive SQTs were also detected. The monthly and daily mean concentrations of most terpenoids, aldehydes and VOAs were highly dependent on the temperature. The highest exponential correlation with temperature was found for a SQT (β-caryophyllene) in summer. The diurnal variations in the concentrations could be explained by sources, sinks and vertical mixing. The diurnal variations in MT concentrations were strongly affected by vertical mixing. Based on the temperature correlations and mixing layer height (MLH), simple proxies were developed for estimating the MT and SQT concentrations. To estimate the importance of different compound groups and compounds in local atmospheric chemistry, reactivity with main oxidants (hydroxyl radical, OH; nitrate radical, NO3; and ozone, O3) and production rates of oxidation products (OxPRs) were calculated. The MTs dominated OH and NO3 radical chemistry, but the SQTs greatly impacted O3 chemistry, even though the concentrations of SQT were 30 times lower than the MT concentrations. SQTs were also the most important for the production of oxidation products. Since the SQTs show high secondary organic aerosol (SOA) yields, the results clearly indicate the importance of SQTs for local SOA production.

scholarly journals Seasonal and diurnal variations of black carbon and organic carbon aerosols in Bangkok

2011 ◽  
Vol 116 (D15) ◽  
Author(s):  
L. K. Sahu ◽  
Y. Kondo ◽  
Y. Miyazaki ◽  
Prapat Pongkiatkul ◽  
N. T. Kim Oanh
Keyword(s):  
Organic Carbon ◽  
Black Carbon ◽  
Diurnal Variations ◽  
Seasonal And Diurnal Variations ◽  
Carbon Aerosols
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