A 3‐D model analysis of the slowdown and interannual variability in the methane growth rate from 1988 to 1997

Wang, James S.; Logan, Jennifer A.; Chen, Xinyu; Duncan, B. N.; Megretskaia, I. A.; Yantosca, Robert M.

doi:10.1029/2003gb002180

Cited by 166 publications

(239 citation statements)

References 99 publications

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“…Palmer et al, 2003), methane (e.g. Wang et al, 2004), and carbon dioxide (e.g. Fraser et al, 2014), and have also recently been used in mercury studies.…”

Section: Inverse Modelmentioning

confidence: 99%

“…30 We construct the observation error covariance matrix, , as a diagonal matrix (dimension 268×268) with the elements the square of the measurement error. We take the measurement error to be the sum in quadrature of the instrumental error and the mean station model-mismatch error (Wang et al, 2004). The model-mismatch error attempts to account for model transport error, and sub-grid scale variations in Hg concentrations.…”

Section: Inverse Modelmentioning

confidence: 99%

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How important is biomass burning in Canada to mercury contamination?

Fraser¹,

Dastoor²,

Ryjkov³

2017

Preprint

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Abstract.Wildfire frequency has increased in past four decades in Canada, and is expected to increase in future as a result of climate change (Wotton et. al. 2010). Mercury (Hg) emissions from biomass burning are known to be significant; however, the impact of biomass burning on air concentration and deposition fluxes in Canada has not been previously quantified. We use 10 estimates of burned biomass from FINN (Fire Inventory from NCAR) and vegetation-specific Emission Factors (EFs) of mercury to investigate the spatiotemporal variability of Hg emissions in Canada. We use Environment and Climate Change Canada's GEM-MACH-Hg (Global Environmental Multi-scale, Modelling Air quality and Chemistry model, mercury version) to quantify the impact of biomass burning in Canada on spatiotemporal variability of air concentrations and deposition fluxes of mercury in Canada. We use North American gaseous elemental mercury (GEM) observations (2010)(2011)(2012)(2013)(2014)(2015), 15 and an inversion technique to optimize the emission factors for GEM for five vegetation types represented in North American fires to constrain the biomass burning impacts of mercury. We use three biomass burning Hg emissions scenarios in Canada to conduct three sets of model simulations for 2010-2015: two scenarios where Hg is emitted only as GEM using literature or optimized EFs, and a third scenario where Hg is emitted as GEM using literature EFs and particle bound mercury (PBM) emitted using the average GEM/PBM ratio from lab measurements. The three biomass burning emission scenarios represent the range of 20 possible values for the impacts of Hg emissions from biomass burning in Canada on Hg concentration and deposition.We find total biomass burning Hg emissions to be highly variable from year to year, and estimate average 2010-2015 total atmospheric biomass burning emissions of Hg in Canada to be between 6-14 t during the biomass burning season (i.e., from May to September), which is 3 -7 times the mercury emission from anthropogenic sources in Canada for this period. On average, 65% of the emissions occur in the provinces west of Ontario. We find that while emissions from biomass burning have a small 25 impact on surface air concentrations of GEM averaged over individual provinces/territories, the impact at individual sites can be as high as 95% during burning events. We estimate average annual mercury deposition from biomass burning in Canada to be between 0.3 -2.8 t, compared to 0.14 t of mercury deposition from anthropogenic sources during the biomass burning season in Canada. Compared to the biomass burning emissions, the relative impact of fires on mercury deposition is shifted eastward, with on average 54% percent of the deposition occurring in provinces west of Ontario. While the relative contribution of Canadian 30 biomass burning to the total mercury deposition over each province/territory is no more than 9% between 2010-2015, the local contribution in some locations (including areas downwind of biomass burning) can be as high as...

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“…Palmer et al, 2003), methane (e.g. Wang et al, 2004), and carbon dioxide (e.g. Fraser et al, 2014), and have also recently been used in mercury studies.…”

Section: Inverse Modelmentioning

confidence: 99%

Section: Inverse Modelmentioning

confidence: 99%

How important is biomass burning in Canada to mercury contamination?

Fraser¹,

Dastoor²,

Ryjkov³

2017

Preprint

View full text Add to dashboard Cite

show abstract

“…although with significant uncertainties still remaining about the exact magnitude of each identified source and sink (Ehhalt et al 2001;Wang et al 2004;Frankenberg et al 2005;do Carmo et al 2006). Keppler et al (2006) recently reported that CH 4 was emitted from dead and living plant material under aerobic conditions.…”

Section: Introductionmentioning

confidence: 99%

A comment on the quantitative significance of aerobic methane release by plants

Kirschbaum

Bruhn

Etheridge

et al. 2006

Functional Plant Biol.

107

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Abstract. A recent study by Keppler et al. (2006; Nature 439, 187-191) demonstrated CH 4 emission from living and dead plant tissues under aerobic conditions. This work included some calculations to extrapolate the findings from the laboratory to the global scale and led various commentators to question the value of planting trees as a greenhouse mitigation option. The experimental work of Keppler et al. (2006) appears to be largely sound, although some concerns remain about the quantification of emission rates. However, whilst accepting their basic findings, we are critical of the method used for extrapolating results to a global scale. Using the same basic information, we present alternative calculations to estimate global aerobic plant CH 4 emissions as 10-60 Mt CH 4 year −1 . This estimate is much smaller than the 62-236 Mt CH 4 year −1 reported in the original study and can be more readily reconciled within the uncertainties in the established sources and sinks in the global CH 4 budget. We also assessed their findings in terms of their possible relevance for planting trees as a greenhouse mitigation option. We conclude that consideration of aerobic CH 4 emissions from plants would reduce the benefit of planting trees by between 0 and 4.4%. Hence, any offset from CH 4 emission is small in comparison to the significant benefit from carbon sequestration. However, much critical information is still lacking about aerobic CH 4 emission from plants. For example, we do not yet know the underlying mechanism for aerobic CH 4 emission, how CH 4 emissions change with light, temperature and the physiological state of leaves, whether emissions change over time under constant conditions, whether they are related to photosynthesis and how they relate to the chemical composition of biomass. Therefore, the present calculations must be seen as a preliminary attempt to assess the global significance from a basis of limited information and are likely to be revised as further information becomes available.

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“…Upper and lower panels show data on 1000-year and 50-year time axes, respectively. Fletcher et al 2004a;Mikaloff Fletcher et al 2004bWang et al 2004Wang et al et al 2004 (W2004); Prinn 2005 (CP2005). A 4-level greyscale is used to distinguish studies, cycling 3 times through the 12 available studies.…”

Section: Acknowledgmentsmentioning

confidence: 99%

Observing a Vulnerable Carbon Cycle

Raupach

Canadell

2008

Ecological Studies

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Abstract:This chapter sketches an analysis of the implications of carbon-climate vulnerability for carbon observation. Carbon-climate vulnerability is defined as a positive or disturbanceamplifying feedback between an aspect of the carbon cycle (a pool or flux) and physical climate, including atmosphere, oceans and the hydrological cycle. Focussing on processes influencing the atmospheric concentrations of CO 2 and CH 4 , we survey the vulnerabilities of the terrestrial part of the global carbon cycle to perturbation under climate change. Important processes include respiration, fire, land use changes, peatlands, permafrost, and the effects of nutrient limitations.Together, these processes create a significant potential climate change impact (expressed as an estimated positive feedback between changes in temperature and atmospheric CO 2 and CH 4 concentrations) which is not negligible in comparison with projected direct consequences of anthropogenic emissions. An important requirement for a global carbon observation system is to track and quantify these vulnerabilities.

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A 3‐D model analysis of the slowdown and interannual variability in the methane growth rate from 1988 to 1997

Cited by 166 publications

References 99 publications

How important is biomass burning in Canada to mercury contamination?

How important is biomass burning in Canada to mercury contamination?

A comment on the quantitative significance of aerobic methane release by plants

Observing a Vulnerable Carbon Cycle

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