A new version of this database is now available at https://doi.org/10.15138/qn55-e011

Global Inventory of Gas Geochemistry Data from Fossil Fuel, Microbial and Biomass Burning Sources, Version 2017

Authors

• Sherwood, O.A., University of Colorado/INSTAAR *
• Schwietzke, S., University of Colorado/CIRES, NOAA/ESRL/GMD
• Arling, V.A., University of Colorado/CIRES, NOAA/ESRL/GMD
• Etiope, G., Istituto Nazionale di Geofisica e Vulcanologia

* corresponding author. Email: owen.sherwood@colorado.edu

https://www.earth-syst-sci-data.net/9/639/2017/

Abstract (from accompanying Earth Systems Science Data journal article):

The concentration of atmospheric methane (CH₄) has more than doubled over the industrial era. To help constrain global and regional CH₄ budgets, inverse (top-down) models incorporate data on the concentration and stable carbon (δ¹³C) and hydrogen (δ²H) isotopic ratios of atmospheric CH₄. These models depend on accurate δ¹³C and δ²H end-member source signatures for each the main emissions categories. Compared with meticulous measurement and calibration of isotopic CH₄ in the atmosphere, there has been relatively little effort to characterize globally representative isotopic source signatures, particularly for fossil fuel sources, since the 1980s. Most global CH₄ budget models have so far relied on outdated source signature values derived from globally non-representative data. To correct this deficiency, we present a comprehensive, globally representative end-member database of the δ¹³C and δ²H of CH₄ from fossil fuel (conventional natural gas, shale gas and coal), modern microbial (wetlands, rice paddies, ruminants, termites, and landfills/waste) and biomass burning sources. Alkane and permanent gas molecular chemistry for fossil fuel categories are also included with the database. The database comprises 10,706 samples (8,732 fossil fuel, 1972 non-fossil) from 190 published references. Mean (unweighted) δ¹³C signatures for fossil fuel CH₄ are significantly lighter than values commonly used in CH₄ budget models, thus highlighting potential under-estimation of fossil fuel CH₄ emissions in previous CH₄ budget models. This living database will be updated every 2-3 years to provide the atmospheric modeling community with the most complete CH₄ source signature data possible.

Version Information:

This 2017 version of the gas geochemistry database supersedes an earlier version (Sherwood, O. A., Schwietzke, S. S., Arling, V. A., and Etiope, G.: Global Inventory of Fossil and Non-fossil Methane δ¹³C Source Signature Measurements for Improved Atmospheric Modeling. Available at: https://doi.org/10.15138/G37P4D, 2016).
The following updates have been made to the 2017 version:

• Fossil Fuel Data: Concentrations of permanent gases and C₁ to C₆ alkanes added
• Fossil Fuel Data: δ¹³C of C₂+ alkanes added to fossil fuel data
• Fossil Fuel Data: δ²H of CH₄ and C2+ alkanes added to fossil fuel data
• Non-Fossil Data: Corrected sample counts and uncertainty type for Cerling et al. (1997)
• Non-Fossil Data: Corrected sample counts for Chanton and Martens (1988)
• Non-Fossil Data: Corrected sample location (Illinois, USA) for Rust (1981)
• Non-Fossil Data: From Whalen et al. (1987), deleted data for termites as abstract does not distriguish between termites and cattle. Added data for rice fields.
• Non-Fossil Data: Added data on δ²H from termites from Whalen et al. (1989)

Fair Use Statement

This database is made freely available to the scientific community and is intended to stimulate and support global methane cycle and other modeling studies. We rely on the ethics and integrity of the user to assure that the authors receive fair credit for their work. Fair credit will depend on the nature of the work and the requirements of the institutions involved. Your use of this database implies an agreement to contact the database co-authors to discuss the nature of the work and the appropriate level of acknowledgement. If the database is essential to the work, or if an important result or conclusion depends on the database, co-authorship may be appropriate. This should be discussed with the co-authors at an early stage in the work. Contacting the co-authors is not optional; if you use the database, you must contact the co-authors. A co-author email distribution list is provided during the database download process, which generates an automated e-mail to the user containing all relevant information.

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