A global ocean methane cycle model was developed using the transport matrix method approach in the MATLAB programming language. In the model, the dissolved methane concentration distribution is controlled by the following processes: (i) equilibration with time-varying atmospheric methane partial pressure; (ii) loss due to first-order oxidation; (iii) in situ production in surface waters, linked to a prescribed phosphate distribution; (iv) transport and mixing by the large-scale circulation, as represented by the Ocean Circulation Inverse Model version 2. The model is first solved for a preindustrial (year 1700) steady-state methane distribution using Newton's method, and then time-stepped forwards to the year 2014.
For a full model description, including the data input and contraints, as well as the key parameterizations, see Wang et al., 2026 (DOI: 10.1073/pnas.2521235123) methods section. The model code is publicly available from the Zenodo archive (DOI: 10.5281/zenodo.15875413.).
The output NetCDF data file accompanies Wang et al., 2026. It contains the global open-ocean distribution of methane as a function of time, predicted by a model in which methane equilibrates with atmosphere, oxidizes in the water column, and is produced in the surface ocean due to degradation of the organic compound methylphosphonate (modeled as a function of PO4 scarcity). Also included are the contributions of pre-industrial methane, anthropogenic methane, and biologically-produced methane to the distribution.
Grid structure
Grid information for the Ocean Circulation Inverse Model used in our simulations of the Methane Production Models. Contains the fields:
- x: Longitude of grid cell centers in degrees East of Prime meridian
- y: Latitude of grid cell centers in degrees North of Equator
- z: Depth of the grid cell center (m)
- M3d: Land/ocean masks (1 = ocean, 0 = land)
- VOL: Volume of each grid cell (m3)
- Year: Years from 1700 to 2014 at which the model results are recorded.
Model output
- CH4: Four-dimensional global ocean methane distribution in nM units (latitude x longitude x depth x time)
- CH4_production: Three-dimensional rate of aerobic methane production, modeled as a function of phosphate scarcity, in μmol m-3 yr-1 units (latitude x longitude x depth)
- PO4_corrected: The global distribution of phosphate (mmol m-3 units) that CH4 production is linked to – this is from World Ocean Atlas 2018 (WOA18) but adjusted using high precision data, to correct for the tendency of WOA18 to overestimate PO4 at low conentrations.
- CH4_pre: Three-dimensional distribution of CH4 (latitude x longitude x depth x time; nM units) that originated from equilibration with the pre-industrial atmosphere.
- CH4_anthro: Three-dimensional distribution of CH4 (latitude x longitude x depth x time; nM units) that accumulated in the ocean (as of 2014) due to equilibration with increasing atmospheric pCH4 (from anthropogenic sources).
- CH4_bio: Three-dimensional distribution of CH4 (latitude x longitude x depth x time; nM units) that originated from biological production in the oxic surface ocean.
