Derived 1800_1899-kg.png, 1800_1899-t.png, 1800_1899-p.png and their numeric caches: CC BY-SA 4.0.
https://creativecommons.org/licenses/by-sa/4.0/
Attribution: Dirk Nikolaus Karger, Michael P. Nobis, Signe Normand, Catherine H. Graham, Niklaus E. Zimmermann (2023), CHELSA-TraCE21k, Climate of the Past 19, 439–456. DOI:10.5194/cp-19-439-2023. Data DOI:10.16904/envidat.211.
Original verified resource: https://zhc-c.s3.cloud.switch.ch/chelsav1/chelsa_trace/
Changes: timeID19 (1800–1899), area averaging from 30 arcsec to 0.5 degrees; mean tas=(tasmin+tasmax)/2; 30-code Koppen classification derived from monthly arrays; current land mask; north of 84N outside source coverage remains missing. This is a model reconstruction, not a measured year 1850.
Licensing provenance: current WSL catalogue lists CC0; EnviDat notes list CC BY 2.0; EnviDat structured metadata link to CC BY-SA 4.0. These derived files are distributed under the stricter CC BY-SA 4.0. Only the new derived climate data and caches are covered; other TerraChronia components retain their licences.
Reproducible processing and source SHA-256 digests: tools/prepare_preindustrial_150.py and tools/data/preindustrial150/*.json in the source package.