Spatial variability of methane: Attributing atmospheric concentrations to emissions

Bamberger, Ines; Stieger, J.; Buchmann, Nina; Eugster, Werner

doi:10.1016/j.envpol.2014.03.028

Cited by 59 publications

(51 citation statements)

References 31 publications

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“…For example, there was a clear diurnal trend with elevated methane each night at the Platteville site. The high time resolution also allows us to observe short-term daytime increases at different sites, which were more sporadic and likely due to local emissions as there is typically more atmospheric mixing in the daytime (Bamberger et al, 2014). In contrast, the Golden site (U-Pod G1) exhibited relatively little variability in methane with differences between this site and the others well above our RMSE, suggesting significant differences in methane concentrations between these sites.…”

Section: Ability To Assess Spatial Variability In the Northern Front mentioning

confidence: 79%

“…While many projects utilize sensors capable of detecting criteria pollutants, advances in the development of metaloxide semiconductor (MOx) sensors have led to sensors ca-pable of detecting methane in settings closer to ambient environmental conditions (Quaranta et al, 1999;Biaggi-Labiosa, 2012). Eugster and Kling (2012) demonstrated the ability of the Figaro TGS 2600 sensor to resolve diurnal methane fluctuations in a remote area of Alaska.…”

Section: Previous Sensor Researchmentioning

confidence: 99%

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Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

et al. 2018

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Abstract. Low-cost sensors have the potential to facilitate the exploration of air quality issues on new temporal and spatial scales. Here we evaluate a low-cost sensor quantification system for methane through its use in two different deployments. The first was a 1-month deployment along the Colorado Front Range and included sites near active oil and gas operations in the Denver-Julesburg basin. The second deployment was in an urban Los Angeles neighborhood, subject to complex mixtures of air pollution sources including oil operations. Given its role as a potent greenhouse gas, new low-cost methods for detecting and monitoring methane may aid in protecting human and environmental health. In this paper, we assess a number of linear calibration models used to convert raw sensor signals into ppm concentration values. We also examine different choices that can be made during calibration and data processing and explore cross sensitivities that impact this sensor type. The results illustrate the accuracy of the Figaro TGS 2600 sensor when methane is quantified from raw signals using the techniques described. The results also demonstrate the value of these tools for examining air quality trends and events on small spatial and temporal scales as well as their ability to characterize an area -highlighting their potential to provide preliminary data that can inform more targeted measurements or supplement existing monitoring networks.

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Section: Ability To Assess Spatial Variability In the Northern Front mentioning

confidence: 79%

Section: Previous Sensor Researchmentioning

confidence: 99%

Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

et al. 2018

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“…The importance of knowing both meteorological conditions and methane (or aerosols, particulate matter, etc.) has been highlighted in previous studies (e.g., Bamberger et al, 2014;Mathieu et al, 2005). Fixedwing systems can cover a vertical and horizontal range of several kilometers and therefore are suitable for investigations throughout the boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous multicopter-based air sampling and sensing of meteorological variables

et al. 2017

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Abstract. The state and composition of the lowest part of the planetary boundary layer (PBL), i.e., the atmospheric surface layer (SL), reflects the interactions of external forcing, land surface, vegetation, human influence and the atmosphere. Vertical profiles of atmospheric variables in the SL at high spatial (meters) and temporal (1 Hz and better) resolution increase our understanding of these interactions but are still challenging to measure appropriately. Traditional ground-based observations include towers that often cover only a few measurement heights at a fixed location. At the same time, most remote sensing techniques and aircraft measurements have limitations to achieve sufficient detail close to the ground (up to 50 m). Vertical and horizontal transects of the PBL can be complemented by unmanned aerial vehicles (UAV). Our aim in this case study is to assess the use of a multicopter-type UAV for the spatial sampling of air and simultaneously the sensing of meteorological variables for the study of the surface exchange processes. To this end, a UAV was equipped with onboard air temperature and humidity sensors, while wind conditions were determined from the UAV's flight control sensors. Further, the UAV was used to systematically change the location of a sample inlet connected to a sample tube, allowing the observation of methane abundance using a ground-based analyzer. Vertical methane gradients of about 0.3 ppm were found during stable atmospheric conditions. Our results showed that both methane and meteorological conditions were in agreement with other observations at the site during the ScaleX-2015 campaign. The multicopter-type UAV was capable of simultaneous in situ sensing of meteorological state variables and sampling of air up to 50 m above the surface, which extended the vertical profile height of existing tower-based infrastructure by a factor of 5.

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“…Advected air parcels can include pollutants from sources lying in the upwind fetch and hence can bias the local CH 4 concentrations, resulting in an overestimation of the NBL budget. In particular, nighttime measurements can include regional information of up to several kilometres upwind (Bamberger et al, 2014). In order to avoid the impact of emissions from upwind sources and to reduce the measurement footprint to an extent, which only includes the barn buildings of the Chamau farmstead, the integration height was set to the height where θ / z ≤ 0 K m −1 (Mathieu et al, 2005;Pattey et al, 2006) with θ being the potential temperature (θ = T (p 0 /p) 1.402 with p 0 = 1000 hPa and p ambient pressure).…”

Section: Budget Flux Calculationmentioning

confidence: 99%

“…In addition, it has been shown that even nighttime observations measured at very low elevations above ground (2 m a.g.l.) carry regional information up to 200 km 2 (Bamberger et al, 2014). An application of the NBL budget approach with F HA ≈ 0, as often done in other studies, will thus result in budgets which represent an enlarged spatial extent not limited to the Chamau farmstead.…”

Section: Using the Nbl Budget Approach In Complex Terrainmentioning

confidence: 99%

Validation of farm-scale methane emissions using nocturnal boundary layer budgets

et al. 2015

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Abstract. This study provides the first experimental validation of Swiss agricultural methane emission estimates at the farm scale. We measured CH 4 concentrations at a Swiss farmstead during two intensive field campaigns in August 2011 and July 2012 to (1) quantify the source strength of livestock methane emissions using a tethered balloon system and (2) to validate inventory emission estimates via nocturnal boundary layer (NBL) budgets. Field measurements were performed at a distance of 150 m from the nearest farm buildings with a tethered balloon system in combination with gradient measurements at eight heights on a 10 m tower to better resolve the near-surface concentrations. Vertical profiles of air temperature, relative humidity, CH 4 concentration, wind speed, and wind direction showed that the NBL was strongly influenced by local transport processes and by the valley wind system. Methane concentrations showed a pronounced time course, with highest concentrations in the second half of the night. NBL budget flux estimates were obtained via a time-space kriging approach. Main uncertainties of NBL budget flux estimates were associated with nonstationary atmospheric conditions and the estimate of the inversion height z i (top of volume integration). The mean NBL budget fluxes of 1.60±0.31 µg CH 4 m −2 s −1 (1.40±0.50 and 1.66 ± 0.20 µg CH 4 m −2 s −1 in 2011 and 2012 respectively) were in good agreement with local inventory estimates based on current livestock number and default emission factors, with 1.29 ± 0.47 and 1.74 ± 0.63 µg CH 4 m −2 s −1 for 2011 and 2012 respectively. This indicates that emission factors used for the national inventory reports are adequate, and we conclude that the NBL budget approach is a useful tool to validate emission inventory estimates.

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Spatial variability of methane: Attributing atmospheric concentrations to emissions

Cited by 59 publications

References 31 publications

Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

Assessing a low-cost methane sensor quantification system for use in complex rural and urban environments

Simultaneous multicopter-based air sampling and sensing of meteorological variables

Validation of farm-scale methane emissions using nocturnal boundary layer budgets

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