Spatial and temporal variation of 13C-signature of methane emitted by a temperate mire ecosystem

2021 ◽  
Author(s):  
Janne Rinne ◽  
Patryk Łakomiec ◽  
Patrik Vestin ◽  
Per Weslien ◽  
Julia Kelly ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Temporal Variation ◽  
Methane Emission ◽  
Trophic Status ◽  
Emission Rate ◽  
Temporal Behavior ◽  
Emission Rates ◽  
Spatial Differences ◽  
Mire Ecosystem ◽  
Methane Emission Rate

<p>The net methane emission of any mire ecosystem results from a combination of biological and physical processes, including methane production by archaea, methane consumption by bacteria, and transport of methane from peat to the atmosphere. The complexity of spatial and temporal behavior of methane emission is connected to these.</p><p><sup>13</sup>C-signature of emitted methane offers us a further constraint to evaluate our hypothesis on the processes leading to the variation of methane emission rates. For example, assuming the spatial variation in methane emission rate at microtopographic scale is due to variation in trophic status or variation in methane consumption, will lead to differences in the relation of methane emission rate and its <sup>13</sup>C-signature, expressed as δ<sup>13</sup>C.</p><p>We have measured the methane emission rates and δ<sup>13</sup>C of emitted methane by six automated chambers at a poor fen ecosystem over two growing seasons. The measurements were conducted at Mycklemossen mire (58°21'N 12°10'E, 80m a.s.l.), Sweden, during 2019-2020. In addition, we measured atmospheric surface layer methane mixing ratios and δ<sup>13</sup>C to obtain larger scale <sup>13</sup>C-signatures by the nocturnal boundary-layer accumulation (NBL) approach. All δ<sup>13</sup>C-signatures were derived using the Keeling-plot approach.</p><p>The collected data shows spatial differences of up to 10-15 ‰ in 10-day averages of δ<sup>13</sup>C-signatures between different chamber locations. Temporal variations of 10-day average δ<sup>13</sup>C-signatures from most chamber locations reached over 5 ‰, while the temporal variation of NBL derived δ<sup>13</sup>C-signature was slightly lower.</p><p>The observed spatial variation in the δ<sup>13</sup>C-signature was somewhat systematic, indicating, especially in the middle of the summers, the main control of spatial variation of methane emission to be the trophic status. The temporal changes, measured at different locations, indicate spatial differences in the temporal dynamics at the microtopographic scale. The temporal behavior of larger scale NBL δ<sup>13</sup>C-signature does not fully correspond to the behavior of the chamber derived average δ<sup>13</sup>C-signature.</p>

Relationship between Methane Emission and Strata Behavior at Island Coal Face

2012 ◽  
Vol 524-527 ◽  
pp. 662-667
Author(s):  
Xin Xian Zhai ◽  
Fu Lin Wang
Keyword(s):  
Coal Mine ◽  
Methane Emission ◽  
Emission Rate ◽  
Main Roof ◽  
Control Measures ◽  
Emission Rates ◽  
Coal Face ◽  
Coal Wall ◽  
Strata Behavior ◽  
Methane Emission Rate

According to the practical conditions of the island coal face in No.2 Coal Mine of Pingdingshan Coal Company Ltd., China, the strata behaviors and methane emission were monitored and their two relationships were analyzed. The results indicate that strata behavior at coal face affects its methane emission rates at coal wall and goaf，which the quantity of methane emission rate at coal face is largely increasing after main roof weighting. So through the monitor of periodic roof weighting time, larger methane emission rate at coal face can be predicted. Then the related methane control measures can be taken timely.

scholarly journals Comparing facility-level methane emission rate estimates at natural gas gathering and boosting stations

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Timothy L. Vaughn ◽  
Clay S. Bell ◽  
Tara I. Yacovitch ◽  
Joseph R. Roscioli ◽  
Scott C. Herndon ◽  
...  
Keyword(s):  
Natural Gas ◽  
Confidence Intervals ◽  
Methane Emission ◽  
Emission Rate ◽  
National Study ◽  
Aircraft Measurements ◽  
Component Level ◽  
Facility Level ◽  
Unburned Fuel ◽  
Methane Emission Rate

Coordinated dual-tracer, aircraft-based, and direct component-level measurements were made at midstream natural gas gathering and boosting stations in the Fayetteville shale (Arkansas, USA). On-site component-level measurements were combined with engineering estimates to generate comprehensive facility-level methane emission rate estimates (“study on-site estimates (SOE)”) comparable to tracer and aircraft measurements. Combustion slip (unburned fuel entrained in compressor engine exhaust), which was calculated based on 111 recent measurements of representative compressor engines, accounts for an estimated 75% of cumulative SOEs at gathering stations included in comparisons. Measured methane emissions from regenerator vents on glycol dehydrator units were substantially larger than predicted by modelling software; the contribution of dehydrator regenerator vents to the cumulative SOE would increase from 1% to 10% if based on direct measurements. Concurrent measurements at 14 normally-operating facilities show relative agreement between tracer and SOE, but indicate that tracer measurements estimate lower emissions (regression of tracer to SOE = 0.91 (95% CI = 0.83–0.99), R2 = 0.89). Tracer and SOE 95% confidence intervals overlap at 11/14 facilities. Contemporaneous measurements at six facilities suggest that aircraft measurements estimate higher emissions than SOE. Aircraft and study on-site estimate 95% confidence intervals overlap at 3/6 facilities. The average facility level emission rate (FLER) estimated by tracer measurements in this study is 17–73% higher than a prior national study by Marchese et al.

scholarly journals METHANE EMISSION FROM PADDY SOIL IN RELATION TO SOIL TEMPERATURE IN TROPICAL REGION

2016 ◽  
Vol 78 (1-2) ◽  
Author(s):  
Fazli P. ◽  
Hasfalina C. M. ◽  
Mohamed Azwan M. Z. ◽  
Umi Kalsom M. S. ◽  
Nor Aini A. R. ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Methane Emission ◽  
Paddy Soil ◽  
Emission Rate ◽  
Paddy Fields ◽  
Tropical Region ◽  
Emission Pattern ◽  
Short Period ◽  
Methane Emission Rate

Methane (CH4) is 21 times more powerful as a greenhouse gas than carbon dioxide. Wetlands including flooded paddy fields are one of the major sources for this gas. Paddy fields are responsible for producing 25 to 54 Tg of CH4 annually. Methane emission rate could be affected by several factors such as irrigation pattern, fertilizer type, soil organic matter and soil temperature. Among them, soil temperature is a determining factor which deserves to be investigated. This study performed with the aim of understanding the effect of soil temperature on the methane emission rate from paddy soil in a short period of time (hourly) and long term (during rice growing season). The results of this study suggest that soil temperature could control the amount of methane emission and there is a positive and strong correlation in both soil temperature and methane emission pattern in short period of time. However, in case of long term trend, other factors such as water management and plant age decreased this correlation from 0.768 to 0.528.

scholarly journals Global annual methane emission rate derived from its current atmospheric mixing ratio and estimated lifetime

2014 ◽  
Vol 32 (3) ◽  
pp. 277-283 ◽  
Author(s):  
G. R. Sonnemann ◽  
M. Grygalashvyly
Keyword(s):  
Methane Emission ◽  
Reasonable Agreement ◽  
Reaction Rate ◽  
Emission Rate ◽  
Annual Growth Rate ◽  
Mixing Ratio ◽  
Atmospheric Lifetime ◽  
Lower Limits ◽  
Methane Emission Rate

Abstract. We use the estimated lifetime of methane (CH4), the current methane concentration, and its annual growth rate to calculate the global methane emission rate. The upper and lower limits of the annual global methane emission rate, depending on loss of CH4 into the stratosphere and methane consuming bacteria, amounts to 648.0 Mt a−1 and 608.0 Mt a−1. These values are in reasonable agreement with satellite and with much more accurate in situ measurements of methane. We estimate a mean tropospheric and mass-weighted temperature related to the reaction rate and employ a mean OH-concentration to calculate a mean methane lifetime. The estimated atmospheric lifetime of methane amounts to 8.28 years and 8.84 years, respectively. In order to improve the analysis a realistic 3D-calculations should be performed.

scholarly journals OpenFOAM solver of the methane behaviour near the coal mine tunnelling face and its application

2021 ◽  
Vol 18 (3) ◽  
pp. 418-427
Author(s):  
Chengwu Li ◽  
Yuechao Zhao ◽  
Yonghang He
Keyword(s):  
Effective Stress ◽  
Methane Emission ◽  
Emission Rate ◽  
Friction Angle ◽  
Adsorption Parameters ◽  
Fractured Zone ◽  
Methane Seepage ◽  
Production Safety ◽  
Coal Damage ◽  
Methane Emission Rate

Abstract The methane near a tunnelling face seriously affects production safety in coal mines. A model considering methane seepage, adsorption, desorption and coal damage processes was established in this research. The open field operation and manipulation (OpenFOAM) solver was compiled to numerically solve the established model. The model is validated against data published in a previous theoretical study. The solver was used to investigate the effect of different parameters on methane emission regularity. This solver demonstrates that the effects of the original stress, coal cohesion and coal internal friction angle on the methane emission rate are limited, but their effects on the width of the fractured zone and effective stress are great. The effects of the initial methane pressure and coal adsorption parameters on the methane emission rate are also notable, but their effects on the width of the fractured zone and effective stress are limited.

scholarly journals Spatiotemporal Variations of Radon Concentration in the Atmosphere of Zhijindong Cave (China)

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 967
Author(s):  
Xu Weng ◽  
Weijun Luo ◽  
Yanwei Wang ◽  
Guangneng Zeng ◽  
Shijie Wang
Keyword(s):  
Air Quality ◽  
Spatial Variation ◽  
Temporal Variation ◽  
Effective Dose ◽  
Radon Concentration ◽  
Cold Season ◽  
Spatiotemporal Variations ◽  
Tour Guides ◽  
Spatial Differences ◽  
Hot Season

Ensuring high air quality in the atmosphere of Zhijindong Cave is essential, for it is one of the most scenic in Asia and has received millions of tourists each year. Radon, as the most important radioactive carcinogen, is a priority and has been measured since just after its opening. However, an artificial exit was opened in 2002, and it is still unclear what the influence of that has been on the radon concentration in the cave atmosphere. In this study, we use RAD7 to monitor the spatiotemporal variations of radon concentration in the atmosphere of Zhijindong Cave for a whole year. The results show that radon concentration is generally higher in the hot season and lower in the cold season, and both with a distinct spatial differences. The highest measured radon concentration is 1691 Bq/m3, which is lower compared with the previous study. The reduced radon concentration could be caused by the strengthened cave ventilation due to the artificial exit. The temporal variation of radon concentration is related to the outside temperature change, while the spatial variation is mostly related to the different cave layers. The effective dose is negligible for tourists, but can be as high as 9.7 mSv for tour guides and 22.6 mSv for photographers.

scholarly journals Is there a relationship between genetic merit and enteric methane emission rate of lactating Holstein-Friesian dairy cows?

animal ◽  
2015 ◽  
Vol 9 (11) ◽  
pp. 1807-1812 ◽  
Author(s):  
L.F. Dong ◽  
T. Yan ◽  
C.P. Ferris ◽  
D.A. McDowell ◽  
A. Gordon
Keyword(s):  
Dairy Cows ◽  
Methane Emission ◽  
Emission Rate ◽  
Genetic Merit ◽  
Holstein Friesian ◽  
Enteric Methane ◽  
Methane Emission Rate

scholarly journals Two Independent Light Dilution Corrections for the SO2 Camera Retrieve Comparable Emission Rates at Masaya Volcano, Nicaragua

2021 ◽  
Vol 13 (5) ◽  
pp. 935
Author(s):  
Matthew Varnam ◽  
Mike Burton ◽  
Ben Esse ◽  
Giuseppe Salerno ◽  
Ryunosuke Kazahaya ◽  
...  
Keyword(s):  
Light Scattering ◽  
Optical Depth ◽  
Camera Calibration ◽  
Wind Direction ◽  
Emission Rate ◽  
Emission Rates ◽  
Depth Images ◽  
Masaya Volcano ◽  
Rapid Changes ◽  
Volcanic Emission

SO2 cameras are able to measure rapid changes in volcanic emission rate but require accurate calibrations and corrections to convert optical depth images into slant column densities. We conducted a test at Masaya volcano of two SO2 camera calibration approaches, calibration cells and co-located spectrometer, and corrected both calibrations for light dilution, a process caused by light scattering between the plume and camera. We demonstrate an advancement on the image-based correction that allows the retrieval of the scattering efficiency across a 2D area of an SO2 camera image. When appropriately corrected for the dilution, we show that our two calibration approaches produce final calculated emission rates that agree with simultaneously measured traverse flux data and each other but highlight that the observed distribution of gas within the image is different. We demonstrate that traverses and SO2 camera techniques, when used together, generate better plume speed estimates for traverses and improved knowledge of wind direction for the camera, producing more reliable emission rates. We suggest combining traverses and the SO2 camera should be adopted where possible.

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