[bl-young]

cc:
Related: #1134

Stack: step after #1152 (by-rename-derive).

What changed? Why?

Draft fill-in for source-resolved USA E snapshots: derive_E_usa_emissions_sources / derive_E_usa_es_long consume the hand-written analysis crosswalk (fbs_to_ceda_emissions_source.csv) and a vendored 123-row ceda EmissionsSource catalog, after HFC speciation on the retained-activity Cornerstone GHG FBS. Nested-split shares and GHG method YAML breakouts are intentionally not applied -- lumped soils / NEU / aviation / res-com lines often stay bundled or unmatched and are omitted from E_USA_ES. E_USA_GAS is unchanged. Analysis README points at this draft path; nested-split recipes in analysis/emissions_source_crosswalk/ remain review-only.

Impact

Next generate_snapshots writes non-stub E_USA_ES / E_USA_ES_LONG with incomplete source coverage; do not publish CEDA-bound bags until ceda readers switch off gas-shaped E_USA_ES. Does not close #1134.

Testing

Unit tests for catalog load, crosswalk load, and specificity tagging.

uv run pytest bedrock/transform/allocation/__tests__/test_emissions_source_crosswalk.py -v
uv run black --check .
uv run ruff check .

Review focus

• Draft scope: crosswalk-only; no nested-split CSV / YAML bake-in
• Crosswalk path stays in analysis; transform only reads it
• Must not be treated as CEDA cutover or as closing Export E by emission source on Cornerstone codes #1134

Heads-up

Hold CEDA year-series / product snapshot cuts until coordinated E reader switch.

[bl-young]

@MoLi7 a more complete, but not yet finished, wiring to the E parquets. I will be doing updated ingestion in CEDA for https://github.com/cornerstone-data/ceda/issues/470 and https://github.com/cornerstone-data/ceda/issues/582.

That way when the time series first draft runs for snapshots they will be much closer to the final outcome

[bl-young]

Draft year-series snapshot cut (throwaway; draft E_USA_ES).

Branch tip: 235509a6c9630a147bc4c26249b8f6012429a6d4 (by-export-E)

Year	GCS prefix	GHA
2017	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2017/	https://github.com/cornerstone-data/bedrock/actions/runs/40796457650
2018	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2018/	https://github.com/cornerstone-data/bedrock/actions/runs/40796463103
2019	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2019/	https://github.com/cornerstone-data/bedrock/actions/runs/40796467442
2020	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2020/	https://github.com/cornerstone-data/bedrock/actions/runs/40796472233
2021	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2021/	https://github.com/cornerstone-data/bedrock/actions/runs/40796477659
2022	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2022/	https://github.com/cornerstone-data/bedrock/actions/runs/40796482848
2023	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2023/	https://github.com/cornerstone-data/bedrock/actions/runs/40796487469
2024	gs://cornerstone-default/snapshots/235509a6c9630a147bc4c26249b8f6012429a6d4_2026_usa_cornerstone_v1_0_2024/	https://github.com/cornerstone-data/bedrock/actions/runs/40796492771

Trust the run log Snapshot prefix: line; Slack success prints the bare SHA path.

[MoLi7]

draft LGTM