Three years of semicontinuous greenhouse gas measurements at the Puy de Dôme station (central France)

Abstract. Three years of greenhouse gas measurements, obtained using a gas chromatograph (GC) system located at the Puy de Dôme station at 1465 m a.s.l. in central France, are presented. The GC system was installed in 2010 at Puy de Dôme and was designed for automatic and accurate semicontinuous measurements of atmospheric carbon dioxide, methane, nitrous oxide and sulfur hexafluoride mole fractions. We present in detail the instrumental setup and the calibration strategy, which together allow the GC to reach repeatabilities of 0.1 μmol mol−1, 1.2 nmol mol−1, 0.3 nmol mol−1 and 0.06 pmol mol−1 for CO2, CH4, N2O and SF6, respectively. The analysis of the 3-year atmospheric time series revealed how the planetary boundary layer height drives the mole fractions observed at a mountain site such as Puy de Dôme where air masses alternate between the planetary boundary layer and the free troposphere. Accurate long-lived greenhouse gas measurements collocated with 222Rn measurements as an atmospheric tracer allowed us to determine the CO2, CH4 and N2O emissions in the catchment area of the station. The derived CO2 surface flux revealed a clear seasonal cycle, with net uptake by plant assimilation in the spring and net emission caused by the biosphere and burning of fossil fuel during the remainder of the year. We calculated a mean annual CO2 flux of 1310 ± 680 t CO2 km−2. The derived CH4 and N2O emissions in the station catchment area were 7.0 ± 4.0 t CH4 km−2 yr−1 and 1.8 ± 1.0 t N2O km−2 yr−1, respectively. Our derived annual CH4 flux is in agreement with the national French inventory, whereas our derived N2O flux is 5 times larger than the same inventory.

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A gas chromatograph system for semi-continuous greenhouse gas measurements at Puy de Dôme station, Central France

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-8-3121-2015 ◽

2015 ◽

Vol 8 (3) ◽

pp. 3121-3170 ◽

Cited By ~ 1

Author(s):

M. Lopez ◽

M. Schmidt ◽

M. Ramonet ◽

J.-L. Bonne ◽

A. Colomb ◽

...

Keyword(s):

Boundary Layer ◽

Time Series ◽

Greenhouse Gases ◽

Planetary Boundary Layer ◽

Catchment Area ◽

Sulfur Hexafluoride ◽

Co2 Flux ◽

N2o Emissions ◽

Gas Chromatograph ◽

Ch4 And N2o

Abstract. Three years of greenhouse gases measurements, obtained using a gas chromatograph (GC) system located at the Puy de Dôme station at 1465 m a.s.l. in Central France are presented. The GC system was installed in 2010 at Puy de Dôme and was designed for automatic and accurate semi-continuous measurements of atmospheric carbon dioxide, methane, nitrous oxide and sulfur hexafluoride mole fractions. We present in detail the instrumental set up and the calibration strategy, which together allow the GC to reach repeatabilities of 0.1 μmol mol−1, 1.2, 0.3 nmol mol−1 and 0.06 pmol mol−1 for CO2, CH4, N2O and SF6, respectively. Comparisons of the atmospheric time series with those obtained using other instruments shown that the GC system meets the World Meteorological Organization recommendations. The analysis of the three-year atmospheric time series revealed how the planetary boundary layer height drives the mole fractions observed at a mountain site such as Puy de Dôme where air masses alternate between the planetary boundary layer and the free troposphere. Accurate long-lived greenhouse gases measurements collocated with 222Rn measurements as an atmospheric tracer, allowed us to determine the CO2, CH4 and N2O emissions in the catchment area of the station. The derived CO2 surface flux revealed a clear seasonal cycle with net uptake by plant assimilation in the spring and net emission caused by the biosphere and burning of fossil fuel during the remainder of the year. We calculated a mean annual CO2 flux of 1150 t(CO2) km−2. The derived CH4 and N2O emissions in the station catchment area were 5.6 t(CH4) km−2 yr−1 and 1.5 t(N2O) km−2 yr−1, respectively. Our derived annual CH4 flux is in agreement with the national French inventory, whereas our derived N2O flux is five times larger than the same inventory.

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Estimating greenhouse gas fluxes from an agriculture-dominated landscape using multiple planetary boundary layer methods

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-14-3231-2014 ◽

2014 ◽

Vol 14 (3) ◽

pp. 3231-3267 ◽

Cited By ~ 2

Author(s):

X. Zhang ◽

X. Lee ◽

T. J. Griffis ◽

J. M. Baker ◽

W. Xiao

Keyword(s):

Greenhouse Gas ◽

Eddy Covariance ◽

Co2 Flux ◽

N2o Emissions ◽

Top Down ◽

Equilibrium Method ◽

Flux Aggregation ◽

Ch4 And N2o ◽

Ghg Fluxes ◽

Tall Tower

Abstract. Quantification of regional greenhouse gas (GHG) fluxes is essential for establishing mitigation strategies and evaluating their effectiveness. Here, we used multiple top-down approaches and multiple trace gas observations at a tall tower to estimate GHG regional fluxes and evaluate the GHG fluxes derived from bottom-up approaches. We first applied the eddy covariance, equilibrium, inverse modeling (CarbonTracker), and flux aggregation methods using three years of carbon dioxide (CO2) measurements on a 244 m tall tower in the Upper Midwest, USA. We then applied the equilibrium method for estimating methane (CH4) and nitrous oxide (N2O) fluxes with one-month high-frequency CH4 and N2O gradient measurements on the tall tower and one-year concentration measurements on a nearby tall tower, and evaluated the uncertainties of this application. The results indicate that: (1) the flux aggregation, eddy covariance, the equilibrium method, and the CarbonTracker product all gave similar seasonal patterns of the regional CO2 flux (105–106 km2), but that the equilibrium method underestimated the July CO2 flux by 52–69%. (2) The annual budget varied among these methods from 74 to −131 g C-CO2 m−2 yr−1, indicating a large uncertainty in the annual CO2 flux estimation. (3) The regional CH4 and N2O emissions according to a top-down method were at least six and two times higher than the emissions from a bottom-up inventory (Emission Database for Global Atmospheric Research), respectively. (4) The global warming potentials of the CH4 and N2O emissions were equal in magnitude to the cooling benefit of the regional CO2 uptake. The regional GHG budget, including both biological and anthropogenic origins, is estimated at 7 ± 160 g CO2 eq m−2 yr−1.

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Greenhouse Gas Emissions from the Tibetan Alpine Grassland: Effects of Nitrogen and Phosphorus Addition

Sustainability ◽

10.3390/su10124454 ◽

2018 ◽

Vol 10 (12) ◽

pp. 4454

Author(s):

Guangshuai Wang ◽

Yueping Liang ◽

Fei Ren ◽

Xiaoxia Yang ◽

Zhaorong Mi ◽

...

Keyword(s):

Tibetan Plateau ◽

Greenhouse Gas ◽

Interactive Effect ◽

Co2 Flux ◽

Growing Season ◽

N2o Emissions ◽

The Tibetan Plateau ◽

Nitrogen And Phosphorus ◽

Annual Budget ◽

Ch4 And N2o

The cycle of key nutrient elements nitrogen (N) and phosphorus (P) has been massively altered by anthropogenic activities. Little is known about the impacts on greenhouse gas (GHG) emission of the large nutrient additions occurring in the alpine grasslands of the Tibetan Plateau. We investigated soil surface emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) under control, N, P and combined nitrogen and phosphorus (NP) additions from July 2011 to September 2012. Compared to the control, CO2 flux significantly increased by 14.6% and 27.4% following P and NP addition, respectively. The interaction of NP addition had a significant influence on CO2 flux during the non-growing season and the spring thaw period. Compared to the control, CH4 flux decreased by 9.9%, 23.2% and 26.7% following N, P and NP additions, respectively, and no interactive effect of NP addition was found in any period. Soil N2O flux was significantly increased 2.6 fold and 3.3 fold, following N and NP addition treatments, respectively, and there was no interaction effect of NP addition together. The contribution of cumulative CO2 emission during the non-growing season was less than 20% of the annual budget, but cumulative CH4 and N2O emissions during the same period can account for 37.3–48.9% and 44.7–59.5% of the annual budget, respectively. Methane and N2O emissions did not increase greatly during the spring thawing period, with contributions of only 0.4–3.6% and 10.3–12.3% of the annual budget, respectively. Our results suggest that N and P addition could increase CO2 and N2O emissions and reduce CH4 emission. Furthermore, although the non-growing season is very cold and long, cumulative CH4 and N2O emissions are considerable during this period and cannot be neglected by future studies evaluating the greenhouse gas emission budget in the Tibetan plateau.

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Estimating regional greenhouse gas fluxes: an uncertainty analysis of planetary boundary layer techniques and bottom-up inventories

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-10705-2014 ◽

2014 ◽

Vol 14 (19) ◽

pp. 10705-10719 ◽

Cited By ~ 14

Author(s):

X. Zhang ◽

X. Lee ◽

T. J. Griffis ◽

J. M. Baker ◽

W. Xiao

Keyword(s):

Greenhouse Gas ◽

Co2 Flux ◽

N2o Emissions ◽

Top Down ◽

Bottom Up ◽

Equilibrium Method ◽

Flux Aggregation ◽

Ch4 And N2o ◽

Ghg Fluxes ◽

Tall Tower

Abstract. Quantification of regional greenhouse gas (GHG) fluxes is essential for establishing mitigation strategies and evaluating their effectiveness. Here, we used multiple top-down approaches and multiple trace gas observations at a tall tower to estimate regional-scale GHG fluxes and evaluate the GHG fluxes derived from bottom-up approaches. We first applied the eddy covariance, equilibrium, inverse modeling (CarbonTracker), and flux aggregation methods using 3 years of carbon dioxide (CO2) measurements on a 244 m tall tower in the upper Midwest, USA. We then applied the equilibrium method for estimating CH4 and N2O fluxes with 1-month high-frequency CH4 and N2O gradient measurements on the tall tower and 1-year concentration measurements on a nearby tall tower, and evaluated the uncertainties of this application. The results indicate that (1) the flux aggregation, eddy covariance, the equilibrium method, and the CarbonTracker product all gave similar seasonal patterns of the regional CO2 flux (105−106 km2, but that the equilibrium method underestimated the July CO2 flux by 52–69%. (2) The annual budget varied among these methods from −54 to −131 g C–CO2 m−2 yr−1, indicating a large uncertainty in the annual CO2 flux estimation. (3) The regional CH4 and N2O emissions according to a top-down method were at least 6 and 2 times higher than the emissions from a bottom-up inventory (Emission Database for Global Atmospheric Research), respectively. (4) The global warming potentials of the CH4 and N2O emissions were equal in magnitude to the cooling benefit of the regional CO2 uptake. The regional GHG budget, including both biological and anthropogenic origins, is estimated at 7 ± 160 g CO2 equivalent m−2 yr−1.

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The nitrogen, carbon and greenhouse gas budget of a grazed, cut and fertilised temperate grassland

10.5194/bg-2016-221 ◽

2016 ◽

Cited By ~ 1

Author(s):

Stephanie K. Jones ◽

Carole Helfter ◽

Margaret Anderson ◽

Mhairi Coyle ◽

Claire Campbell ◽

...

Keyword(s):

Greenhouse Gas ◽

Soil Layer ◽

The Body ◽

Sink Strength ◽

N2o Emissions ◽

N Budget ◽

N Losses ◽

Enteric Fermentation ◽

C And N ◽

Ch4 And N2o

Abstract. Intensively managed grazed grasslands in temperate climates are globally important environments for the exchange of the greenhouse gases (GHGs) carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4). We assessed the N and C budget of a mostly grazed, occasionally cut, and fertilized grassland in SE Scotland by measuring or modelling all relevant imports and exports to the field as well as changes in soil C and N pools over time. The N budget was dominated by import from inorganic and organic fertilisers (21.9 g N m2 yr−1) and losses from leaching (5.3 g N m2 yr−1), N2 emissions and NOx and NH3 volatilisation (6.4 g N m2 yr−1). The efficiency of N use by animal products (meat and wool) averaged 11 %. On average over nine years (2002–2010) the balance of N fluxes suggested that 7.2 ± 4.6 g N m−2 y−1 (mean ± confidence interval at p > 0.95) were stored in the soil. The largest component of the C budget was the net ecosystem exchange of CO2 (NEE), at an average uptake rate of 218 ± 155 g C m−2 y−1 over the nine years. This sink strength was offset by carbon export from the field mainly as harvest (48.9 g C m2 yr−1) and leaching (16.4 g C m2 yr−1). The other export terms, CH4 emissions from the soil, manure applications and enteric fermentation were negligible and only contributed to 0.02–4.2 % of the total C losses. Only a small fraction of C was incorporated into the body of the grazing animals. Inclusion of these C losses in the budget resulted in a C sink strength of 163 ± 140 g C m−2 y−1. On the contrary, soil stock measurements taken in May 2004 and May 2011 indicated that the grassland sequestered N in the 0–60 cm soil layer at 4.51 ± 2.64 g N m−2 y−1 and lost C at a rate of 29.08 ± 38.19 g C m−2 y-1, respectively. Potential reasons for the discrepancy between these estimates are probably an underestimation of C and N losses, especially from leaching fluxes as well as from animal respiration. The average greenhouse gas (GHG) balance of the grassland was −366 ± 601 g CO2 eq m−2 y−1 and strongly affected by CH4 and N2O emissions. The GHG sink strength of the NEE was reduced by 54 % by CH4 and N2O emissions. Enteric fermentation from the ruminating sheep proved to be an important CH4 source, exceeding the contribution of N2O to the GHG budget in some years.

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Effects of Forage Rice Cultivation on Carbon and Greenhouse Gas Balances in a Rice Paddy Field

Atmosphere ◽

10.3390/atmos9120504 ◽

2018 ◽

Vol 9 (12) ◽

pp. 504 ◽

Cited By ~ 2

Author(s):

Fumiaki Takakai ◽

Masahiro Kobayashi ◽

Takashi Sato ◽

Kentaro Yasuda ◽

Yoshihiro Kaneta

Keyword(s):

Greenhouse Gas ◽

Paddy Field ◽

Net Primary Production ◽

Ghg Emissions ◽

Co2 Flux ◽

Rice Paddy ◽

Bare Soil ◽

Rice Cultivation ◽

Forage Rice ◽

Ch4 And N2o

The effects of conversion from staple rice to forage rice on carbon and greenhouse gas (GHG) balances in a paddy field were evaluated. A staple rice plot without the application of livestock manure compost (LMC, S − M plot) and forage rice plots with and without the application of LMC, derived mainly from cattle (2 kg−FW m−2, F + M and F − M plots, respectively), were established. CH4 and N2O fluxes and CO2 flux from a bare soil plot for organic matter decomposition (OMD) were measured. The carbon budget was calculated by subtracting the OMD, CH4 emission, and harvested grain and straw (forage rice only) from the net primary production and LMC. The net GHG balance was calculated by integrating them as CO2 equivalents. There were no significant differences in GHG flux among the plots. Compared to the carbon loss in the S − M plot, the loss increased by harvesting straw and was mitigated by LMC application. The net GHG emission in the F + M plot was significantly lower than that in other plots (1.78 and 2.63−2.77 kg CO2-eq m−2 year−1, respectively). There is a possibility that GHG emissions could be suppressed by forage rice cultivation with the application of LMC.

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Effects of Green Manure Application and Prolonging Mid-Season Drainage on Greenhouse Gas Emission from Paddy Fields in Ehime, Southwestern Japan

Agriculture ◽

10.3390/agriculture9020029 ◽

2019 ◽

Vol 9 (2) ◽

pp. 29 ◽

Cited By ~ 4

Author(s):

Yo Toma ◽

Nukhak Nufita Sari ◽

Koh Akamatsu ◽

Shingo Oomori ◽

Osamu Nagata ◽

...

Keyword(s):

Greenhouse Gas ◽

Green Manure ◽

Greenhouse Gas Emission ◽

Rice Paddy ◽

Paddy Fields ◽

N2o Emissions ◽

Gas Emission ◽

Manure Application ◽

Ch4 And N2o ◽

Rice Paddy Fields

Green manure application helps maintain soil fertility, reduce chemical fertilizer use, and carbon sequestration in the soil. Nevertheless, the application of organic matter in paddy fields induces CH4 and N2O emissions. Prolonging mid-season drainage reduces CH4 emissions in paddy fields. Therefore, the combined effects of green manure application and mid-season drainage prolongation on net greenhouse gas emission (NGHGE) were investigated. Four experimental treatments were set up over a 2-year period: conventional mid-season drainage with (CMG) and without (CM) green manure and prolonged (4 or 7 days) mid-season drainage with (PMG) and without (PM) green manure. Astragalus sinicus L. seeds were sown in autumn and incorporated before rice cultivation. No significant difference in annual CH4 and N2O emissions, heterotrophic respiration, and NGHGE between treatments were observed, indicating that green manure application and mid-season drainage prolongation did not influence NGHGE. CH4 flux decreased drastically in PM and PMG during mid-season drainage under the hot and dry weather conditions. However, increasing applied carbon increases NGHGE because of increased CH4 and Rh. Consequently, combination practice of mid-season drainage prolongation and green manure utilization can be acceptable without changing NGHGE while maintaining grain yield in rice paddy fields under organically managed rice paddy fields.

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Challenges in Linking Atmospheric CO2 Concentrations to Fluxes at Local and Regional Scales

Australian Journal of Botany ◽

10.1071/bt9920697 ◽

1992 ◽

Vol 40 (5) ◽

pp. 697 ◽

Cited By ~ 71

Author(s):

MR Raupach ◽

OT Denmead ◽

FX Dunin

Keyword(s):

Boundary Layer ◽

Planetary Boundary Layer ◽

Co2 Flux ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Wheat Crop ◽

Turbulent Transfer ◽

Near Surface ◽

Scalar Dispersion ◽

Source Sink

We describe relationships between atmospheric CO2 concentration variations and CO2 source-sink distributions, at two important scales between the single plant and the whole earth: the vegetation canopy and the atmospheric planetary boundary layer. For both these scales, it is shown how knowledge of turbulence and scalar dispersion can be applied to infer CO2 source-sink distributions or fluxes from concentration measurements. At the canopy scale, the turbulent transfer of CO2 and other scalars is non-diffusive close to any point source or sink in the canopy, but diffusive at greater distances. This distinction leads to a physically tenable description of turbulent transfer, and thence to an 'inverse method' for finding the vertical profiles of sources and sinks in the canopy from measured concentration profiles. The method is tested with data from a wheat crop. At the scale of the planetary boundary layer, we consider the daily CO2 concentration drawdown (the depression of the near-surface CO2 concentration below the free-atmosphere value) of typically 20-40 ppm. This is determined by both the regionally averaged CO2 uptake at the surface and the growth of the daytime convective boundary layer (CBL). It is shown that, for a column of air which fills the CBL and is moved across the landscape by the mean wind, the net cumulative surface CO2 flux (in mol m-2) is given to a good approximation by h(t)[Cm(t) - C+]/V, where h(t) is CBL depth, Cm(t) the CO2 concentration in the CBL column in mol mol-1, C+ the concentration above the CBL, V the molar volume and time t is measured from the time at which Cm = C+ in the morning, typically about 0800 hours local time. The resulting CO2 flux estimates are regionally averaged over the trajectory followed by the column. This 'CBL budget method' for inferring surface fluxes is compared with direct measurements of CO2 fluxes, with satisfactory results. The technique has application to scalars other than CO2.

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Simulations of the Urban Planetary Boundary Layer in an Arid Metropolitan Area

Journal of Applied Meteorology and Climatology ◽

10.1175/2007jamc1647.1 ◽

2008 ◽

Vol 47 (3) ◽

pp. 752-768 ◽

Cited By ~ 21

Author(s):

Susanne Grossman-Clarke ◽

Yubao Liu ◽

Joseph A. Zehnder ◽

Jerome D. Fast

Keyword(s):

Boundary Layer ◽

Land Use ◽

Planetary Boundary Layer ◽

Mesoscale Model ◽

Potential Temperature ◽

Surface Flux ◽

Metropolitan Region ◽

Radiosonde Data ◽

Near Surface ◽

Better Than

Abstract A modified version of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) was applied to the arid Phoenix, Arizona, metropolitan region. The ability of the model to simulate characteristics of the summertime urban planetary boundary layer (PBL) was tested by comparing model results with observations from two field campaigns conducted in May/June 1998 and June 2001. The modified MM5 included a refined land use/cover classification and updated land use data for Phoenix and bulk approaches of characteristics of the urban surface energy balance. PBL processes were simulated by a version of MM5’s Medium-Range Forecast Model (MRF) scheme that was enhanced by new surface flux and nonlocal mixing approaches. Simulated potential temperature profiles were tested against radiosonde data, indicating that the modified MRF scheme was able to simulate vertical mixing and the evolution and height of the PBL with good accuracy and better than the original MRF scheme except in the late afternoon. During both simulation periods, it is demonstrated that the modified MM5 simulated near-surface air temperatures and wind speeds in the urban area consistently and considerably better than the standard MM5 and that wind direction simulations were improved slightly.

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