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

2014 ◽  
Vol 14 (19) ◽  
pp. 10705-10719 ◽  
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.

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

2014 ◽  
Vol 14 (3) ◽  
pp. 3231-3267 ◽  
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.

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

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.

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

2015 ◽  
Vol 8 (9) ◽  
pp. 3941-3958 ◽  
Author(s):  
M. Lopez ◽  
M. Schmidt ◽  
M. Ramonet ◽  
J.-L. Bonne ◽  
A. Colomb ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Greenhouse Gas ◽  
Planetary Boundary Layer ◽  
Catchment Area ◽  
Sulfur Hexafluoride ◽  
Co2 Flux ◽  
Surface Flux ◽  
N2o Emissions ◽  
Gas Measurements ◽  
Ch4 And N2o

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.

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

2016 ◽  
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.

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

Atmosphere ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 504 ◽  
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.

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

Agriculture ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 29 ◽  
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.

Comparison of top-down and bottom-up estimates of sectoral and regional greenhouse gas emission reduction potentials

Energy Policy ◽  
2009 ◽  
Vol 37 (12) ◽  
pp. 5125-5139 ◽  
Author(s):  
Detlef P. van Vuuren ◽  
Monique Hoogwijk ◽  
Terry Barker ◽  
Keywan Riahi ◽  
Stefan Boeters ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Emission Reduction ◽  
Greenhouse Gas Emission ◽  
Top Down ◽  
Gas Emission ◽  
Bottom Up ◽  
Reduction Potentials ◽  
Greenhouse Gas Emission Reduction

scholarly journals Top-down estimates of European CH<sub>4</sub> and N<sub>2</sub>O emissions based on four different inverse models

2015 ◽  
Vol 15 (2) ◽  
pp. 715-736 ◽  
Author(s):  
P. Bergamaschi ◽  
M. Corazza ◽  
U. Karstens ◽  
M. Athanassiadou ◽  
R. L. Thompson ◽  
...  
Keyword(s):  
Eastern Europe ◽  
Inverse Modelling ◽  
N2o Emissions ◽  
Emission Inventories ◽  
Bottom Up ◽  
Uncertainty Range ◽  
Ch4 Emissions ◽  
Inverse Models ◽  
Ch4 And N2o ◽  
North Western

Abstract. European CH4 and N2O emissions are estimated for 2006 and 2007 using four inverse modelling systems, based on different global and regional Eulerian and Lagrangian transport models. This ensemble approach is designed to provide more realistic estimates of the overall uncertainties in the derived emissions, which is particularly important for verifying bottom-up emission inventories. We use continuous observations from 10 European stations (including 5 tall towers) for CH4 and 9 continuous stations for N2O, complemented by additional European and global discrete air sampling sites. The available observations mainly constrain CH4 and N2O emissions from north-western and eastern Europe. The inversions are strongly driven by the observations and the derived total emissions of larger countries show little dependence on the emission inventories used a priori. Three inverse models yield 26–56% higher total CH4 emissions from north-western and eastern Europe compared to bottom-up emissions reported to the UNFCCC, while one model is close to the UNFCCC values. In contrast, the inverse modelling estimates of European N2O emissions are in general close to the UNFCCC values, with the overall range from all models being much smaller than the UNFCCC uncertainty range for most countries. Our analysis suggests that the reported uncertainties for CH4 emissions might be underestimated, while those for N2O emissions are likely overestimated.

scholarly journals North American terrestrial CO2 uptake largely offset by CH4 and N2O emissions: toward a full accounting of the greenhouse gas budget

2014 ◽  
Vol 129 (3-4) ◽  
pp. 413-426 ◽  
Author(s):  
Hanqin Tian ◽  
Guangsheng Chen ◽  
Chaoqun Lu ◽  
Xiaofeng Xu ◽  
Daniel J. Hayes ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
North American ◽  
N2o Emissions ◽  
Co2 Uptake ◽  
Greenhouse Gas Budget ◽  
Ch4 And N2o

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

2017 ◽  
Vol 14 (8) ◽  
pp. 2069-2088 ◽  
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 ◽  
Enteric Fermentation ◽  
Total N ◽  
Intensively Managed ◽  
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 and occasionally cut and fertilised 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 stocks over time. The N budget was dominated by import from inorganic and organic fertilisers (21.9 g N m−2 a−1) and losses from leaching (5.3 g N m−2 a−1), N2 emissions (2.9 g N m−2 a−1), and NOx and NH3 volatilisation (3.9 g N m−2 a−1), while N2O emission was only 0.6 g N m−2 a−1. The efficiency of N use by animal products (meat and wool) averaged 9.9 % of total N input over only-grazed years (2004–2010). On average over 9 years (2002–2010), the balance of N fluxes suggested that 6.0 ± 5.9 g N m−2 a−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 a−1 over the 9 years. This sink strength was offset by carbon export from the field mainly as grass offtake for silage (48.9 g C m−2 a−1) and leaching (16.4 g C m−2 a−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 a−1. By contrast, 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 a−1 and lost C at a rate of 29.08 ± 38.19 g C m−2 a−1. Potential reasons for the discrepancy between these estimates are probably an underestimation of C 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 yr−1 and was strongly affected by CH4 and N2O emissions. The GHG sink strength of the NEE was reduced by 54 % by CH4 and N2O emissions. Estimated enteric fermentation from 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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