scholarly journals Airborne quantification of net methane and carbon dioxide fluxes from European Arctic wetlands in Summer 2019

2021 ◽  
Vol 380 (2215) ◽  
Author(s):  
Patrick A. Barker ◽  
Grant Allen ◽  
Joseph R. Pitt ◽  
Stéphane J.-B. Bauguitte ◽  
Dominika Pasternak ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Mass Balance ◽  
Land Surface ◽  
Process Models ◽  
Carbon Dioxide Fluxes ◽  
Study Region ◽  
Arctic Wetlands ◽  
Net Uptake ◽  
The Individual ◽  
The Uk

Arctic wetlands and surrounding ecosystems are both a significant source of methane (CH 4 ) and a sink of carbon dioxide (CO 2 ) during summer months. However, precise quantification of this regional CH 4 source and CO 2 sink remains poorly characterized. A research flight using the UK Facility for Airborne Atmospheric Measurement was conducted in July 2019 over an area (approx. 78 000 km 2 ) of mixed peatland and forest in northern Sweden and Finland. Area-averaged fluxes of CH 4 and carbon dioxide were calculated using an aircraft mass balance approach. Net CH 4 fluxes normalized to wetland area ranged between 5.93 ± 1.87 mg m −2  h −1 and 4.44 ± 0.64 mg m −2  h −1 (largest to smallest) over the region with a meridional gradient across three discrete areas enclosed by the flight survey. From largest to smallest, net CO 2 sinks ranged between −513 ± 74 mg m −2  h −1 and −284 ± 89 mg m −2  h −1 and result from net uptake of CO 2 by vegetation and soils in the biosphere. A clear gradient of decreasing bulk and area-averaged CH 4 flux was identified from north to south across the study region, correlated with decreasing peat bog land area from north to south identified from CORINE land cover classifications. While N 2 O mole fraction was measured, no discernible gradient was measured over the flight track, but a minimum flux threshold using this mass balance method was calculated. Bulk (total area) CH 4 fluxes determined via mass balance were compared with area-weighted upscaled chamber fluxes from the same study area and were found to agree well within measurement uncertainty. The mass balance CH 4 fluxes were found to be significantly higher than the CH 4 fluxes reported by many land-surface process models compiled as part of the Global Carbon Project. There was high variability in both flux distribution and magnitude between the individual models. This further supports previous studies that suggest that land-surface models are currently ill-equipped to accurately capture carbon fluxes inthe region. This article is part of a discussion meeting issue 'Rising methane: is warming feeding warming? (part 2)'.

scholarly journals Country-scale greenhouse gas budgets using shipborne measurements: a case study for the UK and Ireland

2019 ◽  
Vol 19 (5) ◽  
pp. 3043-3063 ◽  
Author(s):  
Carole Helfter ◽  
Neil Mullinger ◽  
Massimo Vieno ◽  
Simon O'Doherty ◽  
Michel Ramonet ◽  
...  
Keyword(s):  
United Kingdom ◽  
Mass Balance ◽  
Air Temperature ◽  
Central Region ◽  
Waste Treatment ◽  
Methane Emissions ◽  
The United Kingdom ◽  
Carbon Dioxide Co2 ◽  
The Individual ◽  
The Uk

Abstract. We present a mass balance approach to estimate the seasonal and annual budgets of carbon dioxide (CO2) and methane (CH4) of the United Kingdom (excluding Scotland) and the Republic of Ireland from concentration measurements taken on a ferry along the east coast of the United Kingdom over a 3-year period (2015–2017). We estimate the annual emissions of CH4 to be 2.55±0.48 Tg, which is consistent with the combined 2.29 Tg reported to the United Nations Framework Convention on Climate Change by the individual countries. The net CO2 budget (i.e. including all anthropogenic and biogenic sources and sinks of CO2) is estimated at 881.0±125.8 Tg, with a net biogenic contribution of 458.7 Tg (taken as the difference between the estimated net emissions and the inventory value, which accounts for anthropogenic emissions only). The largest emissions for both gases were observed in a broad latitudinal band (52.5–54∘ N), which coincides with densely populated areas. The emissions of both gases were seasonal (maxima in winter and minima in summer), strongly correlated with natural gas usage and, to a lesser extent, also anti-correlated with mean air temperature. Methane emissions exhibited a statistically significant anti-correlation with air temperature at the seasonal timescale in the central region spanning 52.8–54.2∘ N, which hosts a relatively high density of waste treatment facilities. Methane emissions from landfills have been shown to sometimes increase with decreasing air temperature due to changes in the CH4-oxidising potential of the topsoil, and we speculate that the waste sector contributes significantly to the CH4 budget of this central region. This study brings independent verification of the emission budgets estimated using alternative products (e.g. mass balance budgets by aircraft measurements, inverse modelling, inventorying) and offers an opportunity to investigate the seasonality of these emissions, which is usually not possible.

scholarly journals Methane and carbon dioxide fluxes and their regional scalability for the European Arctic wetlands during the MAMM project in summer 2012

2014 ◽  
Vol 14 (23) ◽  
pp. 13159-13174 ◽  
Author(s):  
S. J. O'Shea ◽  
G. Allen ◽  
M. W. Gallagher ◽  
K. Bower ◽  
S. M. Illingworth ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Land Surface ◽  
Regional Scale ◽  
Local Area ◽  
The Arctic ◽  
Emission Flux ◽  
Carbon Dioxide Fluxes ◽  
Airborne Measurements ◽  
Simple Boundary

Abstract. Airborne and ground-based measurements of methane (CH4), carbon dioxide (CO2) and boundary layer thermodynamics were recorded over the Fennoscandian landscape (67–69.5° N, 20–28° E) in July 2012 as part of the MAMM (Methane and other greenhouse gases in the Arctic: Measurements, process studies and Modelling) field campaign. Employing these airborne measurements and a simple boundary layer box model, net regional-scale (~ 100 km) fluxes were calculated to be 1.2 ± 0.5 mg CH4 h−1 m−2 and −350 ± 143 mg CO2 h−1 m−2. These airborne fluxes were found to be relatively consistent with seasonally averaged surface chamber (1.3 ± 1.0 mg CH4 h−1 m−2) and eddy covariance (1.3 ± 0.3 mg CH4 h−1 m−2 and −309 ± 306 mg CO2 h−1 m−2) flux measurements in the local area. The internal consistency of the aircraft-derived fluxes across a wide swath of Fennoscandia coupled with an excellent statistical comparison with local seasonally averaged ground-based measurements demonstrates the potential scalability of such localised measurements to regional-scale representativeness. Comparisons were also made to longer-term regional CH4 climatologies from the JULES (Joint UK Land Environment Simulator) and HYBRID8 land surface models within the area of the MAMM campaign. The average hourly emission flux output for the summer period (July–August) for the year 2012 was 0.084 mg CH4 h−1 m−2 (minimum 0.0 and maximum 0.21 mg CH4 h−1 m−2) for the JULES model and 0.088 mg CH4 h−1 m−2 (minimum 0.0008 and maximum 1.53 mg CH4 h−1 m−2) for HYBRID8. Based on these observations both models were found to significantly underestimate the CH4 emission flux in this region, which was linked to the under-prediction of the wetland extents generated by the models.

scholarly journals Scaling and balancing carbon dioxide fluxes in a heterogeneous tundra ecosystem of the Lena River Delta

2019 ◽  
Vol 16 (13) ◽  
pp. 2591-2615 ◽  
Author(s):  
Norman Rößger ◽  
Christian Wille ◽  
David Holl ◽  
Mathias Göckede ◽  
Lars Kutzbach
Keyword(s):  
Carbon Dioxide ◽  
Flood Plain ◽  
Heterogeneous Surface ◽  
Sink Strength ◽  
Carbon Dioxide Fluxes ◽  
Lena River ◽  
Net Uptake ◽  
Vegetation Class ◽  
Lena River Delta ◽  
Tundra Ecosystems

Abstract. The current assessments of the carbon turnover in the Arctic tundra are subject to large uncertainties. This problem can (inter alia) be ascribed to both the general shortage of flux data from the vast and sparsely inhabited Arctic region, as well as the typically high spatiotemporal variability of carbon fluxes in tundra ecosystems. Addressing these challenges, carbon dioxide fluxes on an active flood plain situated in the Siberian Lena River Delta were studied during two growing seasons with the eddy covariance method. The footprint exhibited a heterogeneous surface, which generated mixed flux signals that could be partitioned in such a way that both respiratory loss and photosynthetic gain were obtained for each of two vegetation classes. This downscaling of the observed fluxes revealed a differing seasonality in the net uptake of bushes (−0.89 µmol m−2 s−1) and sedges (−0.38 µmol m−2 s−1) in 2014. That discrepancy, which was concealed in the net signal, resulted from a comparatively warm spring in conjunction with an early snowmelt and a varying canopy structure. Thus, the representativeness of footprints may adversely be affected in response to prolonged unusual weather conditions. In 2015, when air temperatures on average corresponded to climatological means, both vegetation-class-specific flux rates were of similar magnitude (−0.69 µmol m−2 s−1). A comprehensive set of measures (e.g. phenocam) corroborated the reliability of the partitioned fluxes and hence confirmed the utility of flux decomposition for enhanced flux data analysis. This scrutiny encompassed insights into both the phenological dynamic of individual vegetation classes and their respective functional flux to flux driver relationships with the aid of ecophysiologically interpretable parameters. For comparison with other sites, the decomposed fluxes were employed in a vegetation class area-weighted upscaling that was based on a classified high-resolution orthomosaic of the flood plain. In this way, robust budgets that take the heterogeneous surface characteristics into account were estimated. In relation to the average sink strength of various Arctic flux sites, the flood plain constitutes a distinctly stronger carbon dioxide sink. Roughly 42 % of this net uptake, however, was on average offset by methane emissions lowering the sink strength for greenhouse gases. With growing concern about rising greenhouse gas emissions in high-latitude regions, providing robust carbon budgets from tundra ecosystems is critical in view of accelerating permafrost thaw, which can impact the global climate for centuries.

scholarly journals Methane and carbon dioxide fluxes and their regional scalability for the European Arctic wetlands during the MAMM project in summer 2012

2014 ◽  
Vol 14 (6) ◽  
pp. 8455-8494 ◽  
Author(s):  
S. J. O'Shea ◽  
G. Allen ◽  
M. W. Gallagher ◽  
K. Bower ◽  
S. M. Illingworth ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Boundary Layer ◽  
Land Surface ◽  
Regional Scale ◽  
Local Area ◽  
The Arctic ◽  
Emission Flux ◽  
Carbon Dioxide Fluxes ◽  
Airborne Measurements ◽  
Simple Boundary

Abstract. Airborne and ground-based measurements of methane (CH4), carbon dioxide (CO2) and boundary layer thermodynamics were recorded over the Fennoscandian wetlands in July 2012 as part of the MAMM (Methane and other greenhouse gases in the Arctic – Measurements, process studies and Modelling) field campaign. Employing these airborne measurements and a~simple boundary layer box model, net regional scale (~100 km) fluxes were calculated to be 1.2 ± 0.5 mg CH4 h−1 m−2 and −350 ± 143 mg CO2 h−1 m−2. These airborne fluxes were found to be relatively consistent with seasonally-averaged surface chamber (1.3 ± 1.0 mg CH4 h−1 m−2) and eddy covariance (1.3 ± 0.3 mg CH4 h−1 m−2 and −309 ± 306 mg CO2 h−1 m−2) flux measurements in the local area. The internal consistency of the aircraft-derived fluxes across a wide swath of Fennoscandia coupled with an excellent statistical comparison with local seasonally-averaged ground-based measurements demonstrates the potential scalability of such localised measurements to regional scale representivity. Comparisons were also made to longer term regional CH4 climatologies from the JULES (Joint UK Land Environment Simulator) and Hybrid8 land surface models within the area of the MAMM campaign. The average hourly emission flux output for the summer period (July–August) across the years 1980 to 2010 was 0.054 mg CH4 h−1 m−2 (minimum 0.0 and maximum 0.38 mg CH4 h−1 m−2) for the JULES model and 0.073 mg CH4 h−1 m−2 (minimum −0.0018 and maximum 4.62 mg CH4 h−1 m−2) for Hybrid8. Based on these observations both models were found to significantly underestimate the CH4 emission flux in this region, which was linked to the under prediction of the wetland extents generated by the models.

scholarly journals The Global Methane Budget: 2000–2012

2016 ◽  
Author(s):  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Ben Poulter ◽  
Anna Peregon ◽  
Philippe Ciais ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Chemistry ◽  
Land Surface ◽  
Data Driven ◽  
Anthropogenic Emissions ◽  
Methane Cycle ◽  
Modelling Framework ◽  
Methane Budget ◽  
The Individual ◽  
Global Emissions

Abstract. The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due to a shorter atmospheric lifetime and a stronger warming potential than carbon dioxide, is challenged by the still unexplained changes of atmospheric CH4 over the past decade. Emissions and concentrations of CH4 are continuing to increase making CH4 the second most important human-induced greenhouse gas after carbon dioxide. Two major difficulties in reducing uncertainties come from the large variety of diffusive CH4 sources that overlap geographically, and from the destruction of CH4 by the very short-lived hydroxyl radical (OH). To address these difficulties, we have established a consortium of multi-disciplinary scientists under the umbrella of the Global Carbon Project to synthesize and stimulate research on the methane cycle, and producing regular (~biennial) updates of the global methane budget. This consortium includes atmospheric physicists and chemists, biogeochemists of surface and marine emissions, and socio-economists who study anthropogenic emissions. Following Kirschke et al. (2013), we propose here the first version of a living review paper that integrates results of top-down studies (T-D, exploiting atmospheric observations within an atmospheric inverse-modelling framework) and bottom-up models, inventories, and data-driven approaches (B-U, including process-based models for estimating land surface emissions and atmospheric chemistry, and inventories for anthropogenic emissions, data-driven extrapolations). For the 2003–2012 decade, global methane emissions are estimated by T-D inversions at 558 Tg CH4 yr−1 (range [540–568]). About 60 % of global emissions are anthropogenic (range [50–65 %]). B-U approaches suggest larger global emissions (736 Tg CH4 yr−1 [596–884]) mostly because of larger natural emissions from individual sources such as inland waters, natural wetlands and geological sources. Considering the atmospheric constraints on the T-D budget, it is likely that some of the individual emissions reported by the B-U approaches are overestimated, leading to too large global emissions. Latitudinal data from T-D emissions indicate a predominance of tropical emissions (~64 % of the global budget,

Sisterhood and After

2019 ◽  
Author(s):  
Margaretta Jolly
Keyword(s):  
Oral History ◽  
Women's Liberation ◽  
Equal Rights ◽  
Collective Memories ◽  
Women’S Liberation ◽  
Two Generations ◽  
Personal Accounts ◽  
The Individual ◽  
The Uk ◽  
Cultural Taste

This ground-breaking history of the UK Women’s Liberation Movement explores the individual and collective memories of women at its heart. Spanning at least two generations and four nations, and moving through the tumultuous decades from the 1970s to the present, the narrative is powered by feminist oral history, notably the British Library’s Sisterhood and After: The Women’s Liberation Oral History Project. The book mines these precious archives to bring fresh insight into the lives of activists and the campaigns and ideas they mobilised. It navigates still-contested questions of class, race, violence, and upbringing—as well as the intimacies, sexualities and passions that helped fire women’s liberation—and shows why many feminists still regard notions of ‘equality’ or even ‘equal rights’ as insufficient. It casts new light on iconic campaigns and actions in what is sometimes simplified as feminism’s ‘second wave’, and enlivens a narrative too easily framed by ideological abstraction with candid, insightful, sometimes painful personal accounts of national and less well-known women activists. They describe lives shaped not only by structures of race, class, gender, sexuality and physical ability, but by education, age, love and cultural taste. At the same time, they offer extraordinary insights into feminist lifestyles and domestic pleasures, and the crossovers and conflicts between feminists. The work draws on oral history’s strength as creative method, as seen with its conclusion, where readers are urged to enter the archives of feminist memory and use what they find there to shape their own political futures.

Punk as Folk: Continuities and Tensions in the UK and Beyond

2020 ◽  
Author(s):  
Pete Dale
Keyword(s):  
Folk Music ◽  
Music Making ◽  
Collective Creativity ◽  
Living Tradition ◽  
Wide Range ◽  
The Us ◽  
The Common ◽  
The Individual ◽  
The Uk

Numerous claims have been made by a wide range of commentators that punk is somehow “a folk music” of some kind. Doubtless there are several continuities. Indeed, both tend to encourage amateur music-making, both often have affiliations with the Left, and both emerge at least partly from a collective/anti-competitive approach to music-making. However, there are also significant tensions between punk and folk as ideas/ideals and as applied in practice. Most obviously, punk makes claims to a “year zero” creativity (despite inevitably offering re-presentation of at least some existing elements in every instance), whereas folk music is supposed to carry forward a tradition (which, thankfully, is more recognized in recent decades as a subject-to-change “living tradition” than was the case in folk’s more purist periods). Politically, meanwhile, postwar folk has tended more toward a socialist and/or Marxist orientation, both in the US and UK, whereas punk has at least rhetorically claimed to be in favor of “anarchy” (in the UK, in particular). Collective creativity and competitive tendencies also differ between the two (perceived) genre areas. Although the folk scene’s “floor singer” tradition offers a dispersal of expressive opportunity comparable in some ways to the “anyone can do it” idea that gets associated with punk, the creative expectation of the individual within the group differs between the two. Punk has some similarities to folk, then, but there are tensions, too, and these are well worth examining if one is serious about testing out the common claim, in both folk and punk, that “anyone can do it.”

Ecosystem modeling of methane and carbon dioxide fluxes for boreal forest sites

2001 ◽  
Vol 31 (2) ◽  
pp. 208-223 ◽  
Author(s):  
Christopher Potter ◽  
Jill Bubier ◽  
Patrick Crill ◽  
Peter Lafleur
Keyword(s):  
Carbon Dioxide ◽  
Boreal Forest ◽  
Land Surface ◽  
Net Primary Production ◽  
Ground Cover ◽  
Methane Flux ◽  
Growing Season ◽  
Ecosystem Model ◽  
Heat Fluxes ◽  
Water Levels

Predicted daily fluxes from an ecosystem model for water, carbon dioxide, and methane were compared with 1994 and 1996 Boreal Ecosystem–Atmosphere Study (BOREAS) field measurements at sites dominated by old black spruce (Picea mariana (Mill.) BSP) (OBS) and boreal fen vegetation near Thompson, Man. Model settings for simulating daily changes in water table depth (WTD) for both sites were designed to match observed water levels, including predictions for two microtopographic positions (hollow and hummock) within the fen study area. Water run-on to the soil profile from neighboring microtopographic units was calibrated on the basis of daily snowmelt and rainfall inputs to reproduce BOREAS site measurements for timing and magnitude of maximum daily WTD for the growing season. Model predictions for daily evapotranspiration rates closely track measured fluxes for stand water loss in patterns consistent with strong controls over latent heat fluxes by soil temperature during nongrowing season months and by variability in relative humidity and air temperature during the growing season. Predicted annual net primary production (NPP) for the OBS site was 158 g C·m–2 during 1994 and 135 g C·m–2 during 1996, with contributions of 75% from overstory canopy production and 25% from ground cover production. Annual NPP for the wetter fen site was 250 g C·m–2 during 1994 and 270 g C·m–2 during 1996. Predicted seasonal patterns for soil CO2 fluxes and net ecosystem production of carbon both match daily average estimates at the two sites. Model results for methane flux, which also closely match average measured flux levels of –0.5 mg CH4·m–2·day–1 for OBS and 2.8 mg CH4·m–2·day–1 for fen sites, suggest that spruce areas are net annual sinks of about –0.12 g CH4·m–2, whereas fen areas generate net annual emissions on the order of 0.3–0.85 g CH4·m–2, depending mainly on seasonal WTD and microtopographic position. Fen hollow areas are predicted to emit almost three times more methane during a given year than fen hummock areas. The validated model is structured for extrapolation to regional simulations of interannual trace gas fluxes over the entire North America boreal forest, with integration of satellite data to characterize properties of the land surface.

Sign in / Sign up

Export Citation Format

Share Document