BER launches Environmental System Science Program. Visit our new website under construction!

U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Improving Global Methane Emission Predictions
Published: September 13, 2016
Posted: November 22, 2016

A multiscale comparison of modeled and observed seasonal methane emissions in northern wetlands.

The Science
Wetlands are the largest global natural methane (CH4) source, yet predictive capability of land models is low. In a recent study, researchers improved the methane module in the Community Land Model (CLM) and Accelerated Climate Modeling for Energy (ACME) Land Model (ALM) and compared predictions with tower and aircraft observations and atmospheric inversions. The findings highlight new observations and model requirements to improve global CH4 predictions.

The Impact
Model changes substantially improved CH4 emission predictions compared to observations. Cold season CH4 emissions estimates remain biased low, motivating more observations during this period. Large CH4 emissions uncertainties also are generated by uncertainties in wetland hydrology.

Summary
The study compared wetland CH4 emission model predictions with site- to regional-scale observations. A comparison of the CH4 fluxes with eddy flux data highlighted needed changes to the model’s estimate of aerenchyma area, which were implemented and tested. The model modifications substantially reduced biases in CH4 emissions when compared with CarbonTracker CH4 predictions. CLM4.5 CH4 emission predictions agree well with Alaskan growing season (May–September) CarbonTracker CH4 predictions and site-level observations. However, the model underestimated CH4 emissions in the cold season (October–April). The monthly atmospheric CH4 mole fraction enhancements due to wetland emissions also were assessed using the Weather Research and Forecasting-Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) model and compared with measurements from the Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) campaign. Both the tower and aircraft analyses confirm the underestimate of cold season CH4 emissions. The greatest uncertainties in predicting the seasonal CH4 cycle are from the wetland extent, cold season CH4 production, and CH4 transport processes. Predicted CH4 emissions remain uncertain, but the study’s findings show that benchmarking against observations across spatial scales can inform model structural and parameter improvements.

Contacts
BER Program Managers
Daniel Stover, Jared DeForest, and Renu Joseph
SC-23.1
Daniel.Stover@science.doe.gov (301-903-0289)
Jared.DeForest@science.doe.gov (301-903-1678)
Renu.joseph@science.doe.gov

Principal Investigator
William J. Riley
Lawrence Berkeley National Laboratory
Berkeley, CA 94720
wjriley@lbl.gov

Funding
Funding for this study was provided by the Regional and Global Climate Model (RGCM) program and Next-Generation Ecosystem Experiments (NGEE)–Arctic project of the Office of Biological and Environmental Research, within the U.S. Department of Energy (DOE) Office of Science, under the under contract # DE-AC02-05CH11231.

Publications
Xu, X., W.J. Riley, C.D. Koven, et al. "A multi-scale comparison of modeled and observed seasonal methane emissions in northern wetlands." Biogeosciences 13, 5043–5056 (2016). [DOI:10.5194/bg-13-5043-2016]

Topic Areas:

  • Research Area: Earth and Environmental Systems Modeling
  • Research Area: Terrestrial Ecosystem Science
  • Research Area: Carbon Cycle, Nutrient Cycling

Division: SC-33.1 Earth and Environmental Sciences Division, BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

Mar 23, 2021
Molecular Connections from Plants to Fungi to Ants
Lipids transfer energy and serve as an inter-kingdom communication tool in leaf-cutter ants&rsqu [more...]

Mar 19, 2021
Microbes Use Ancient Metabolism to Cycle Phosphorus
Microbial cycling of phosphorus through reduction-oxidation reactions is older and more widespre [more...]

Feb 22, 2021
Warming Soil Means Stronger Microbe Networks
Soil warming leads to more complex, larger, and more connected networks of microbes in those soi [more...]

Jan 27, 2021
Labeling the Thale Cress Metabolites
New data pipeline identifies metabolites following heavy isotope labeling.

Analysis [more...]

Aug 31, 2020
Novel Bacterial Clade Reveals Origin of Form I Rubisco
Objectives

  • All plant biomass is sourced from the carbon-fixing enzyme Rub [more...]

List all highlights (possible long download time)