scholarly journals Methane emissions from an oil sands tailings pond: a quantitative comparison of fluxes derived by different methods

2021 ◽  
Vol 14 (3) ◽  
pp. 1879-1892
Author(s):  
Yuan You ◽  
Ralf M. Staebler ◽  
Samar G. Moussa ◽  
James Beck ◽  
Richard L. Mittermeier
Keyword(s):  
Eddy Covariance ◽  
Oil Sands ◽  
Dispersion Model ◽  
Flux Measurement ◽  
Regulatory Compliance ◽  
High Temporal Resolution ◽  
Detailed Knowledge ◽  
Fugitive Emissions ◽  
Inverse Dispersion ◽  
Flux Chambers

Abstract. Tailings ponds in the Alberta oil sands region are significant sources of fugitive emissions of methane to the atmosphere, but detailed knowledge on spatial and temporal variabilities is lacking due to limitations of the methods deployed under current regulatory compliance monitoring programs. To develop more robust and representative methods for quantifying fugitive emissions, three micrometeorological flux methods (eddy covariance, gradient, and inverse dispersion) were applied along with traditional flux chambers to determine fluxes over a 5-week period. Eddy covariance flux measurements provided the benchmark. A method is presented to directly calculate stability-corrected eddy diffusivities that can be applied to vertical gas profiles for gradient flux estimation. Gradient fluxes were shown to agree with eddy covariance within 18 %, while inverse dispersion model flux estimates were 30 % lower. Fluxes were shown to have only a minor diurnal cycle (15 % variability) and were weakly dependent on wind speed, air, and water surface temperatures. Flux chambers underestimated the fluxes by 64 % in this particular campaign. The results show that the larger footprint together with high temporal resolution of micrometeorological flux measurement methods may result in more robust estimates of the pond greenhouse gas emissions.

scholarly journals Methane emissions from an oil sands tailings pond: A quantitative comparison of fluxes derived by different methods

2020 ◽  
Author(s):  
Yuan You ◽  
Ralf M. Staebler ◽  
Samar G. Moussa ◽  
James Beck ◽  
Richard L. Mittermeier
Keyword(s):  
Eddy Covariance ◽  
Oil Sands ◽  
Dispersion Model ◽  
Regulatory Compliance ◽  
Detailed Knowledge ◽  
Inverse Dispersion ◽  
Eddy Diffusivities ◽  
Flux Measurements ◽  
Flux Chambers ◽  
A Minor

Abstract. Tailings ponds in the Alberta Oil Sands Region are significant sources of fugitive emissions of methane to the atmosphere, but detailed knowledge on spatial and temporal variabilities is lacking due to limitations of the methods deployed under current regulatory compliance monitoring programs. To develop more robust and representative methods for quantifying these emissions, three micrometeorological flux methods were applied along with traditional flux chambers to determine fluxes over a 5-week period. Eddy covariance flux measurements provided the benchmark. A method is presented to directly calculate stability-corrected eddy diffusivities that can be applied to vertical gas profiles for gradient flux estimation. Gradient fluxes were shown to agree with eddy covariance within 7 %, and inverse dispersion model fluxes within 11 %, with an overall uncertainty of 28 % for the calculated mean flux. Fluxes were shown to have only a minor diurnal cycle (18 % variability) and to be mostly independent of wind speed, air and water surface temperatures. Flux chambers underestimated the fluxes by a factor of 2 in this particular campaign. These measurements indicate that the larger footprint of micrometeorological measurements results in more robust emission estimates representing the whole pond.

scholarly journals Quantifying fugitive gas emissions from an oil sands tailings pond with open-path Fourier transform infrared measurements

2021 ◽  
Vol 14 (2) ◽  
pp. 945-959
Author(s):  
Yuan You ◽  
Samar G. Moussa ◽  
Lucas Zhang ◽  
Long Fu ◽  
James Beck ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Oil Sands ◽  
Measurement Techniques ◽  
Flux Measurement ◽  
Fourier Transform Infrared ◽  
Inverse Dispersion ◽  
Nh3 Emission ◽  
Open Path ◽  
Infrared Measurements ◽  
Emission Fluxes

Abstract. Fugitive emissions from tailings ponds contribute significantly to facility emissions in the Alberta oil sands, but details on chemical emission profiles and the temporal and spatial variability of emissions to the atmosphere are sparse, since flux measurement techniques applied for compliance monitoring have their limitations. In this study, open-path Fourier transform infrared spectroscopy was evaluated as a potential alternative method for quantifying spatially representative fluxes for various pollutants (methane, ammonia, and alkanes) from a particular pond, using vertical-flux-gradient and inverse-dispersion methods. Gradient fluxes of methane averaged 4.3 g m−2 d−1 but were 44 % lower than nearby eddy covariance measurements, while inverse-dispersion fluxes agreed to within 30 %. With the gradient fluxes method, significant NH3 emission fluxes were observed (0.05 g m−2 d−1, 42 t yr−1), and total alkane fluxes were estimated to be 1.05 g m−2 d−1 (881 t yr−1), representing 9.6 % of the facility emissions.

scholarly journals Quantifying fugitive gas emissions from an oil sands tailings pond with open-path FTIR measurements

2020 ◽  
Author(s):  
Yuan You ◽  
Samar G. Moussa ◽  
Lucas Zhang ◽  
Long Fu ◽  
James Beck ◽  
...  
Keyword(s):  
Oil Sands ◽  
Measurement Techniques ◽  
Flux Measurement ◽  
Inverse Dispersion ◽  
Nh3 Emission ◽  
Open Path ◽  
Temporal And Spatial Variability ◽  
Emission Fluxes ◽  
Eddy Covariance Measurements ◽  
Potential Alternative

Abstract. Fugitive emissions from tailings ponds contribute significantly to facility emissions in the Alberta Oil Sands, but details on chemical emission profiles and the temporal and spatial variability of emissions to the atmosphere are sparse, since flux measurement techniques applied for compliance monitoring have their limitations. In this study, open-path Fourier transform infrared spectroscopy was evaluated as a potential alternative method for quantifying spatially representative fluxes for various pollutants (methane, ammonia, and alkanes) from a particular pond, using vertical flux gradient and inverse dispersion methods. Gradient fluxes of methane averaged 3.7 g m−2 d−1 but were 40 % lower than nearby eddy covariance measurements, while inverse dispersion fluxes agreed to within 11 %. Significant NH3 emission fluxes were observed (0.11 g m−2 d−1 (92 tonnes y−1)), and total alkane fluxes were estimated to be 1.33 g m−2 d−1 (1120 tonnes y−1), representing 12 % of the facility emissions.

Quantification of fugitive emissions from an oil sands tailings pond by eddy covariance

Fuel ◽  
2019 ◽  
Vol 237 ◽  
pp. 457-464 ◽  
Author(s):  
Lucas Zhang ◽  
Sunny Cho ◽  
Zaher Hashisho ◽  
Casandra Brown
Keyword(s):  
Eddy Covariance ◽  
Oil Sands ◽  
Fugitive Emissions ◽  
Tailings Pond ◽  
Oil Sands Tailings

scholarly journals Correction of Eddy Covariance Based Crop ET Considering the Heat Flux Source Area

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 281
Author(s):  
Stuart L. Joy ◽  
José L. Chávez
Keyword(s):  
Heat Flux ◽  
Eddy Covariance ◽  
Agricultural Land ◽  
Flux Measurement ◽  
Source Area ◽  
Mean Bias Error ◽  
Bias Error ◽  
Crop Water ◽  
The Past ◽  
Measurement Results

Eddy covariance (EC) systems are being used to measure sensible heat (H) and latent heat (LE) fluxes in order to determine crop water use or evapotranspiration (ET). The reliability of EC measurements depends on meeting certain meteorological assumptions; the most important of such are horizontal homogeneity, stationarity, and non-advective conditions. Over heterogeneous surfaces, the spatial context of the measurement must be known in order to properly interpret the magnitude of the heat flux measurement results. Over the past decades, there has been a proliferation of ‘heat flux source area’ (i.e., footprint) modeling studies, but only a few have explored the accuracy of the models over heterogeneous agricultural land. A composite ET estimate was created by using the estimated footprint weights for an EC system in the upwind corner of four fields and separate ET estimates from each of these fields. Three analytical footprint models were evaluated by comparing the composite ET to the measured ET. All three models performed consistently well, with an average mean bias error (MBE) of about −0.03 mm h−1 (−4.4%) and root mean square error (RMSE) of 0.09 mm h−1 (10.9%). The same three footprint models were then used to adjust the EC-measured ET to account for the fraction of the footprint that extended beyond the field of interest. The effectiveness of the footprint adjustment was determined by comparing the adjusted ET estimates with the lysimetric ET measurements from within the same field. This correction decreased the absolute hourly ET MBE by 8%, and the RMSE by 1%.

scholarly journals A new Lagrangian in-time particle simulation module (Itpas v1) for atmospheric particle dispersion

2021 ◽  
Vol 14 (4) ◽  
pp. 2205-2220
Author(s):  
Matthias Faust ◽  
Ralf Wolke ◽  
Steffen Münch ◽  
Roger Funk ◽  
Kerstin Schepanski
Keyword(s):  
Boundary Layer ◽  
Particle Transport ◽  
Dispersion Model ◽  
Weather Forecast ◽  
Forecast Model ◽  
Particle Dispersion ◽  
Particle Simulation ◽  
High Temporal Resolution ◽  
Atmospheric Particle ◽  
Trajectory Models

Abstract. Trajectory models are intuitive tools for airflow studies. But in general, they are limited to non-turbulent, i.e. laminar flow, conditions. Therefore, trajectory models are not particularly suitable for investigating airflow within the turbulent atmospheric boundary layer. To overcome this, a common approach is handling the turbulent uncertainty as a random deviation from a mean path in order to create a statistic of possible solutions which envelops the mean path. This is well known as the Lagrangian particle dispersion model (LPDM). However, the decisive factor is the representation of turbulence in the model, for which widely used models such as FLEXPART and HYSPLIT use an approximation. A conceivable improvement could be the use of a turbulence parameterisation approach based on the turbulent kinetic energy (TKE) at high temporal resolution. Here, we elaborated this approach and developed the LPDM Itpas, which is coupled online to the German Weather Service's mesoscale weather forecast model COSMO. It benefits from the prognostically calculated TKE as well as from the high-frequency wind information. We demonstrate the model's applicability for a case study on agricultural particle emission in eastern Germany. The results obtained are discussed with regard to the model's ability to describe particle transport within a turbulent boundary layer. Ultimately, the simulations performed suggest that the newly introduced method based on prognostic TKE sufficiently represents the particle transport.

scholarly journals Eddy-covariance flux measurements with a weight-shift microlight aircraft

2012 ◽  
Vol 5 (7) ◽  
pp. 1699-1717 ◽  
Author(s):  
S. Metzger ◽  
W. Junkermann ◽  
M. Mauder ◽  
F. Beyrich ◽  
K. Butterbach-Bahl ◽  
...  
Keyword(s):  
Heat Flux ◽  
Eddy Covariance ◽  
Low Cost ◽  
Sensible Heat Flux ◽  
Flux Measurement ◽  
Wind Measurement ◽  
Airborne Measurements ◽  
Weight Shift ◽  
Flux Measurements

Abstract. The objective of this study is to assess the feasibility and quality of eddy-covariance flux measurements from a weight-shift microlight aircraft (WSMA). Firstly, we investigate the precision of the wind measurement (σu,v ≤ 0.09 m s−1, σw = 0.04 m s−1), the lynchpin of flux calculations from aircraft. From here, the smallest resolvable changes in friction velocity (0.02 m s−1), and sensible- (5 W m−2) and latent (3 W m−2) heat flux are estimated. Secondly, a seven-day flight campaign was performed near Lindenberg (Germany). Here we compare measurements of wind, temperature, humidity and respective fluxes between a tall tower and the WSMA. The maximum likelihood functional relationship (MLFR) between tower and WSMA measurements considers the random error in the data, and shows very good agreement of the scalar averages. The MLFRs for standard deviations (SDs, 2–34%) and fluxes (17–21%) indicate higher estimates of the airborne measurements compared to the tower. Considering the 99.5% confidence intervals, the observed differences are not significant, with exception of the temperature SD. The comparison with a large-aperture scintillometer reveals lower sensible heat flux estimates at both tower (−40 to −25%) and WSMA (−25–0%). We relate the observed differences to (i) inconsistencies in the temperature and wind measurement at the tower and (ii) the measurement platforms' differing abilities to capture contributions from non-propagating eddies. These findings encourage the use of WSMA as a low cost and highly versatile flux measurement platform.

scholarly journals Towards a standardized processing of Net Ecosystem Exchange measured with eddy covariance technique: algorithms and uncertainty estimation

2006 ◽  
Vol 3 (4) ◽  
pp. 571-583 ◽  
Author(s):  
D. Papale ◽  
M. Reichstein ◽  
M. Aubinet ◽  
E. Canfora ◽  
C. Bernhofer ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Net Ecosystem Exchange ◽  
Terrestrial Ecosystem ◽  
Climatic Conditions ◽  
High Temporal Resolution ◽  
Eddy Covariance Technique ◽  
Forest Sites ◽  
European Database

Abstract. Eddy covariance technique to measure CO2, water and energy fluxes between biosphere and atmosphere is widely spread and used in various regional networks. Currently more than 250 eddy covariance sites are active around the world measuring carbon exchange at high temporal resolution for different biomes and climatic conditions. In this paper a new standardized set of corrections is introduced and the uncertainties associated with these corrections are assessed for eight different forest sites in Europe with a total of 12 yearly datasets. The uncertainties introduced on the two components GPP (Gross Primary Production) and TER (Terrestrial Ecosystem Respiration) are also discussed and a quantitative analysis presented. Through a factorial analysis we find that generally, uncertainties by different corrections are additive without interactions and that the heuristic u*-correction introduces the largest uncertainty. The results show that a standardized data processing is needed for an effective comparison across biomes and for underpinning inter-annual variability. The methodology presented in this paper has also been integrated in the European database of the eddy covariance measurements.

scholarly journals Air-Sea Fluxes of CO<sub>2</sub> and CH<sub>4</sub> from the Penlee Point Atmospheric Observatory on the South West Coast of the UK

2016 ◽  
Author(s):  
M. Yang ◽  
T. G. Bell ◽  
F. E. Hopkins ◽  
V. Kitidis ◽  
P. W. Cazenave ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
West Coast ◽  
Phytoplankton Bloom ◽  
Flux Measurement ◽  
Sensible Heat ◽  
The South ◽  
Eddy Covariance Method ◽  
Spring Phytoplankton Bloom ◽  
South West ◽  
South West Coast

Abstract. We present air-sea fluxes of carbon dioxide (CO2), methane (CH4), momentum, and sensible heat measured by the eddy covariance method from the recently established Penlee Point Atmospheric Observatory (PPAO) on the South West coast of the United Kingdom. Measurements from the southwest direction (background marine air) at three different sampling heights (approximately 15, 18, 27 m above mean sea level, AMSL) in three different periods during 2014–2015 are shown. At sampling heights ≥ 18 m AMSL, measured fluxes of momentum and sensible heat demonstrate reasonable agreement with their expected transfer rates over the open ocean. This confirms the suitability of PPAO for air-sea exchange measurements. We observed reductions in the air-to-sea fluxes of CO2 from spring to summer in both years, which coincided with the breakdown of the spring phytoplankton bloom. At all sampling heights, mean CH4 fluxes were positive, suggesting marine emissions. Higher CH4 fluxes were observed during rising tides (20&amp;pm;3; 29&amp;pm;6; 38&amp;pm;3 μmole m−2 d−1 at 15, 27, 18 m AMSL) than during falling tides (14&amp;pm;2; 21&amp;pm;5; 22&amp;pm;2 μmole m−2 d−1, respectively), consistent with an elevated CH4 source from an estuarine outflow driven by local tidal circulation. Based on observations at PPAO, we also estimate the detection limit of the eddy covariance CH4 flux measurement to be ~20 μmole m−2 d−1 over hourly timescales (~4 μmole m−2 d−1 over 24 hours).

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