slv.inversion.priors.load_epa_prior#

slv.inversion.priors.load_epa_prior(out_grid, flux_times, flux_freq=None, bbox=None, extent=None, units=None, express=False, return_regridder=False)[source]#

EPA gridded CH4 inventory (v2) regridded to out_grid and aligned to flux_times.

Both options use EPA’s express product (27 sectors including post-meter, 2012-2020), so they hold the same annual emissions and differ only in seasonal timing. Sectors are summed and regridded conservatively (needs xesmf). With express=False it is scaled by month: sectors with monthly scale factors vary by month, the rest hold their annual rate. express=True keeps the annual rates (paper 1). A flux time after the inventory ends takes its last year (EPA 2020 for 2021-2023), see align_to_flux_times().

Parameters:

  • out_grid (xr.DataArray) – Target lon/lat grid.

  • flux_times (pd.DatetimeIndex) – Start of each flux interval.

  • flux_freq (str, optional) – Flux interval; the inventory is averaged to it when coarser than the inventory.

  • bbox (tuple, optional) – Clip the inventory before regridding.

  • extent (tuple, optional) – Clip the inventory before regridding.

  • units (str, optional) – Convert to these units (e.g. "umol/m2/s").

  • express (bool) – Keep the annual rates (True, paper 1) instead of scaling by month (False).

  • return_regridder (bool) – Also return the xesmf.Regridder.

Returns:

The prior flux named "flux".

Return type:

pd.Series or (pd.Series, xesmf.Regridder)