---
license: cc-by-4.0
pretty_name: jax-gcm boundary conditions and emissions
tags:
  - climate
  - atmospheric-science
  - emissions
  - boundary-conditions
---

# jax-gcm boundary conditions and emissions

Input data for [jax-gcm](https://github.com/climate-analytics-lab/jax-gcm)
(`jcm`), a fully differentiable atmospheric GCM in JAX. Two tiers:

## `products/` — grid-independent source products

| store | contents | source |
|---|---|---|
| `ceds_anthro.zarr` | anthropogenic SO2/BC/OC/NH3 flux, sector-summed, 0.5°, monthly 1850–2023 + PI (1850–59) / PD (2005–14) climatologies | CEDS-CMIP-2025-04-18 (input4MIPs CMIP7) |
| `bb4cmip7.zarr` | open-burning SO2/BC/OC/NH3 flux, 0.25°, monthly 1850–2023 + PI/PD climatologies | DRES-CMIP-BB4CMIP7-2-0 |
| `era5_land_climo_2005-2014_0p25.nc` | skin/soil temperature, 3-layer soil water, snow depth, albedo, land-sea mask, 0.25° | ERA5 (NCAR RDA d633001) |
| `sso/sso_gmted2010_*.nc` | Lott & Miller (1997) subgrid-orography statistics from the 30″ GMTED2010 DEM | USGS GMTED2010 |

All fluxes are kg m⁻² s⁻¹. Regridding always starts from these — never
from an already-regridded bundle.

## `bundles/` — per-grid, ready for the model

For each grid (`t63` 96×192, `t106` 160×320 Gaussian; `ne30pg3`
native columns), the files `jcm.Model` reads directly:

- `terrain.nc` — orography + land-sea mask + six SSO fields
  (jcm-canonical layout)
- `forcing_{pi,pd}.nc` — 12-month SST/sea-ice (PCMDI-AMIP-1-1-10) +
  ERA5 land-surface climatology. **PI SST/ice is the 1870–1879 mean**,
  the earliest observed decade — no observational 1850 SST exists.
- `emissions_{pi,pd}.nc` — per-super-sector surface flux
  (`surface_combustion`, `biomass_burning`) × (SO2, BC, OC)
- `dms.nc`, `dust.nc` — Lana et al. (2011) seawater DMS; CAM dust
  erodibility
- `<grid>_l{47,95}/ozone_{pi,pd}.nc` — FZJ-CMIP-ozone-1-0 pre-interpolated
  to the ECHAM hybrid levels
- `<grid>_l{47,95}/oxidants_{1850,2014}.nc` — CAM OH/NO3/O3/H2O2
  (L26 source, clamped above the CAM lid)

## Usage

```python
from jcm.data.remote import bundle_file
terrain = bundle_file("t63", "terrain.nc")
ozone = bundle_file("t63_l47", "ozone_pd.nc")
```

`registry.json` lists every file with size and sha256.

## Licences and provenance

Emissions, ozone and SST/sea-ice derive from CMIP7 input4MIPs products
(CC-BY-4.0). ERA5 derivatives are provided under the Copernicus licence
terms. GMTED2010 is a public-domain USGS product. See each file's
attributes for the exact source path and processing history.