Janusz Eluszkiewicz

Anthropogenic emissions of methane in the United States

Significance Successful regulation of greenhouse gas emissions requires knowledge of current methane emission sources. Existing state regulations in California and Massachusetts require ∼15% greenhouse gas emissions reductions from current levels by 2020. However, government estimates for total US methane emissions may be biased by 50%, and estimates of individual source sectors are even more uncertain. This study uses atmospheric methane observations to reduce this level of uncertainty. We find greenhouse gas emissions from agriculture and fossil fuel extraction and processing (i.e., oil and/or natural gas) are likely a factor of two or greater than cited in existing studies. Effective national and state greenhouse gas reduction strategies may be difficult to develop without appropriate estimates of methane emissions from these source sectors. This study quantitatively estimates the spatial distribution of anthropogenic methane sources in the United States by combining comprehensive atmospheric methane observations, extensive spatial datasets, and a high-resolution atmospheric transport model. Results show that current inventories from the US Environmental Protection Agency (EPA) and the Emissions Database for Global Atmospheric Research underestimate methane emissions nationally by a factor of ∼1.5 and ∼1.7, respectively. Our study indicates that emissions due to ruminants and manure are up to twice the magnitude of existing inventories. In addition, the discrepancy in methane source estimates is particularly pronounced in the south-central United States, where we find total emissions are ∼2.7 times greater than in most inventories and account for 24 ± 3% of national emissions. The spatial patterns of our emission fluxes and observed methane–propane correlations indicate that fossil fuel extraction and refining are major contributors (45 ± 13%) in the south-central United States. This result suggests that regional methane emissions due to fossil fuel extraction and processing could be 4.9 ± 2.6 times larger than in EDGAR, the most comprehensive global methane inventory. These results cast doubt on the US EPA’s recent decision to downscale its estimate of national natural gas emissions by 25–30%. Overall, we conclude that methane emissions associated with both the animal husbandry and fossil fuel industries have larger greenhouse gas impacts than indicated by existing inventories.

Assessment of ground-based atmospheric observations for verification of greenhouse gas emissions from an urban region

International agreements to limit greenhouse gas emissions require verification to ensure that they are effective and fair. Verification based on direct observation of atmospheric greenhouse gas concentrations will be necessary to demonstrate that estimated emission reductions have been actualized in the atmosphere. Here we assess the capability of ground-based observations and a high-resolution (1.3 km) mesoscale atmospheric transport model to determine a change in greenhouse gas emissions over time from a metropolitan region. We test the method with observations from a network of CO2 surface monitors in Salt Lake City. Many features of the CO2 data were simulated with excellent fidelity, although data-model mismatches occurred on hourly timescales due to inadequate simulation of shallow circulations and the precise timing of boundary-layer stratification and destratification. Using two optimization procedures, monthly regional fluxes were constrained to sufficient precision to detect an increase or decrease in emissions of approximately 15% at the 95% confidence level. We argue that integrated column measurements of the urban dome of CO2 from the ground and/or space are less sensitive than surface point measurements to the redistribution of emitted CO2 by small-scale processes and thus may allow for more precise trend detection of emissions from urban regions.

Emissions of CH4 and N2O over the United States and Canada based on a receptor-oriented modeling framework and COBRA-NA atmospheric observations

Reference ARVE-ARTICLE-2009-003doi:10.1029/2008GL034031View record in Web of Science Record created on 2009-04-22, modified on 2016-08-08

Atmospheric inverse estimates of methane emissions from Central California

Atmospheric Inverse Estimates of Methane Emissions from Central California Chuanfeng Zhao 1 , Arlyn E. Andrews 2 , Laura Bianco 2,5 , Janusz Eluszkiewicz 3 , Adam Hirsch 2,5 , Clinton MacDonald 4 , Thomas Nehrkorn 3 , Marc L. Fischer 1 Environmental Energy Technology Division, Lawrence Berkeley National Lab, Berkeley, CA, USA Earth System Research Laboratory, NOAA, Boulder, CO, USA Atmospheric and Environmental Research, Inc., Lexington, MA, USA Sonoma Technology, Inc., Petaluma, CA, USA Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO, USA

Sensitivity of Age-of-Air Calculations to the Choice of Advection Scheme

The age of air has recently emerged as a diagnostic of atmospheric transport unaffected by chemical parameterizations, and the features in the age distributions computed in models have been interpreted in terms of the models’ large-scale circulation field. This study shows, however, that in addition to the simulated large-scale circulation, three-dimensional age calculations can also be affected by the choice of advection scheme employed in solving the tracer continuity equation. Specifically, using the 3.08 latitude 3 3.68 longitude and 40 vertical level version of the Geophysical Fluid Dynamics Laboratory SKYHI GCM and six online transport schemes ranging from Eulerian through semi-Lagrangian to fully Lagrangian, it will be demonstrated that the oldest ages are obtained using the nondiffusive centered-difference schemes while the youngest ages are computed with a semi-Lagrangian transport (SLT) scheme. The centered-difference schemes are capable of producing ages older than 10 years in the mesosphere, thus eliminating the ‘‘young bias’’ found in previous age-of-air calculations. At this stage, only limited intuitive explanations can be advanced for this sensitivity of age-of-air calculations to the choice of advection scheme. In particular, age distributions computed online with the National Center for Atmospheric Research Community Climate Model (MACCM3) using different varieties of the SLT scheme are substantially older than the SKYHI SLT distribution. The different varieties, including a noninterpolating-in-thevertical version (which is essentially centered-difference in the vertical), also produce a narrower range of age distributions than the suite of advection schemes employed in the SKYHI model. While additional MACCM3 experiments with a wider range of schemes would be necessary to provide more definitive insights, the older and less variable MACCM3 age distributions can plausibly be interpreted as being due to the semi-implicit semiLagrangian dynamics employed in the MACCM3. This type of dynamical core (employed with a 60-min time step) is likely to reduce SLT’s interpolation errors that are compounded by the short-term variability characteristic of the explicit centered-difference dynamics employed in the SKYHI model (time step of 3 min). In the extreme case of a very slowly varying circulation, the choice of advection scheme has no effect on two-dimensional (latitude‐ height) age-of-air calculations, owing to the smooth nature of the transport circulation in 2D models. These results suggest that nondiffusive schemes may be the preferred choice for multiyear simulations of tracers not overly sensitive to the requirement of monotonicity (this category includes many greenhouse gases). At the same time, age-of-air calculations offer a simple quantitative diagnostic of a scheme’s long-term diffusive properties and may help in the evaluation of dynamical cores in multiyear integrations. On the other hand, the sensitivity of the computed ages to the model numerics calls for caution in using age of air as a diagnostic of a GCM’s large-scale circulation field.

Evaluation of Lagrangian Particle Dispersion Models with Measurements from Controlled Tracer Releases

AbstractThree widely used Lagrangian particle dispersion models (LPDMs)—the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), Stochastic Time-Inverted Lagrangian Transport (STILT), and Flexible Particle (FLEXPART) models—are evaluated with measurements from the controlled tracer-release experiments Cross-Appalachian Tracer Experiment (CAPTEX) and Across North America Tracer Experiment (ANATEX). The LPDMs are run forward in time driven by identical meteorological inputs from the North American Regional Reanalysis (NARR) and several configurations of the Weather Research and Forecasting (WRF) model, and the simulations of tracer concentrations are evaluated against the measurements with a ranking procedure derived from the combination of four statistical parameters. The statistical evaluation reveals that all three LPDMs have comparable skill in simulating the tracer plumes when driven by the same meteorological inputs, indicating that the differences in their formulations play a secondary ...

Methane emissions from Alaska in 2012 from CARVE airborne observations

Significance Alaska emitted 2.1 ± 0.5 Tg CH4 during the 2012 growing season, an unexceptional amount despite widespread permafrost thaw and other evidence of climate change in the region. Our results are based on more than 30 airborne measurement flights conducted by CARVE from May to September 2012 over Alaska. Methane emissions peaked in summer and remained high in to the fall. Emissions from boreal regions were notably larger than from North Slope tundra. To our knowledge, this is the first regional study of methane emissions from Arctic and boreal regions over a growing season. Our estimates reinforce and refine global models, and they provide an important baseline against which to measure future changes associated with climate change. We determined methane (CH4) emissions from Alaska using airborne measurements from the Carbon Arctic Reservoirs Vulnerability Experiment (CARVE). Atmospheric sampling was conducted between May and September 2012 and analyzed using a customized version of the polar weather research and forecast model linked to a Lagrangian particle dispersion model (stochastic time-inverted Lagrangian transport model). We estimated growing season CH4 fluxes of 8 ± 2 mg CH4⋅m−2⋅d−1 averaged over all of Alaska, corresponding to fluxes from wetlands of 56−13+22 mg CH4⋅m−2⋅d−1 if we assumed that wetlands are the only source from the land surface (all uncertainties are 95% confidence intervals from a bootstrapping analysis). Fluxes roughly doubled from May to July, then decreased gradually in August and September. Integrated emissions totaled 2.1 ± 0.5 Tg CH4 for Alaska from May to September 2012, close to the average (2.3; a range of 0.7 to 6 Tg CH4) predicted by various land surface models and inversion analyses for the growing season. Methane emissions from boreal Alaska were larger than from the North Slope; the monthly regional flux estimates showed no evidence of enhanced emissions during early spring or late fall, although these bursts may be more localized in time and space than can be detected by our analysis. These results provide an important baseline to which future studies can be compared.

Regional sources of nitrous oxide over the United States: Seasonal variation and spatial distribution

This paper presents top-down constraints on the magnitude, spatial distribution, and seasonality of nitrous oxide (N{sub 2}O) emissions over the central United States. We analyze data from tall towers in 2004 and 2008 using a high resolution Lagrangian particle dispersion model paired with both geostatistical and Bayesian inversions. Our results indicate peak N{sub 2}O emissions in June with a strong seasonal cycle. The spatial distribution of sources closely mirrors data on fertilizer application with particularly large N{sub 2}O sources over the US Cornbelt. Existing inventories for N{sub 2}O predict emissions that differ substantially from the inverse model results in both seasonal cycle and magnitude. We estimate a total annual N{sub 2}O budget over the central US of 0.9-1.2 TgN/yr and an extrapolated budget for the entire US and Canada of 2.1-2.6 TgN/yr. By this estimate, the US and Canada account for 12-15% of the total global N{sub 2}O source or 32-39% of the global anthropogenic source as reported by the Intergovernmental Panel on Climate Change in 2007.

Compaction and internal structure of mimas

Abstract The coupled thermal and porosity evolution of Mimas is investigated on the basis of the two-phase flow approach developed for partially molten rock. The constitutive relations necessary to solve the resulting set of equations are taken from the work on hot isostatic pressing and sintering of porous materials under the assumption that the fluid-dynamical behavior of ice-rock mixtures is dominated by rheology of pure ice. The calculations show that for an initial porosity distribution determined by plastic yielding porosity explains the value γ = 0.883 ± 0.033 of the dimensionless moment of inertia for Mimas if the ambient temperature of formation T e is lower than 120°K and surface porosity ψ 0 is greater than 25%. For the nominal value T e = 80 K the value of γ can be explained only if ψ 0 falls within the range 30–40%. This is an interesting result as such porosities are indeed expected for uncompressed granular mixtures. The model also suggests higher internal temperatures (∼ 140°K at the center for ψ 0 = 0.36) than previously obtained in “cold accretion” models and the presence of a regolith several tens of kilometers thick.

WRF Simulations of the Urban Circulation in the Salt Lake City Area for CO2 Modeling

AbstractA recent National Research Council report highlighted the potential utility of atmospheric observations and models for detecting trends in concentrated emissions from localized regions, such as urban areas. The Salt Lake City (SLC), Utah, area was chosen for a pilot study to determine the feasibility of using ground-based sensors to identify trends in anthropogenic urban emissions over a range of time scales (from days to years). The Weather Research and Forecasting model (WRF) was combined with a Lagrangian particle dispersion model and an emission inventory to model carbon dioxide (CO2) concentrations that can be compared with in situ measurements. An accurate representation of atmospheric transport requires a faithful modeling of the meteorological conditions. This study examines in detail the ability of different configurations of WRF to reproduce the observed local and mesoscale circulations, and the diurnal evolution of the planetary boundary layer (PBL) in the SLC area. Observations from th...