ArWen companion data distribution (Python package "gpuwm-data")
Copyright 2026 ArWen contributors

Licensed under the Apache License, Version 2.0. The third-party datasets
and tables packaged here retain their own licenses and notices. Per-asset
provenance -- sources, generation recipes, SHA-256 pins -- is recorded in
the PROVENANCE.md file beside each asset directory.

This distribution is DATA. It contains no Python except one eleven-line
__init__.py and a VERSION file, no compiled code, and no vendored
dependency tree. Its NOTICE is therefore shorter than the gpuwm NOTICE and
covers a different set of things; where a paragraph here has a fuller
counterpart there, it says so.

Where a licence requires its text to be reproduced rather than merely
named, it is reproduced. The texts are in the licenses/ directory, which
ships in both the wheel and the source distribution through the
license-files declaration in pyproject.toml and lands in an installed
wheel at gpuwm_data-<version>.dist-info/licenses/licenses/. Some also sit
beside the data they belong to, which is where a reader looking at one
directory rather than at the whole distribution will find them first.

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WRF / NCAR / UCAR

ArWen is an independent implementation. It is not affiliated with or
endorsed by the National Center for Atmospheric Research (NCAR) or the
University Corporation for Atmospheric Research (UCAR). The Weather
Research and Forecasting (WRF) model, developed at NCAR, is the
transcription and verification authority for ArWen's WRF-derived
mechanisms (WRF v4.6.1, https://github.com/wrf-model/WRF).

WRF is not released under an open-source licence: UCAR places it in the
public domain and requests a notice. That request is honoured here by
reproduction rather than paraphrase. WRF v4.6.1 LICENSE.txt is at
licenses/LICENSE-WRF-public-domain.txt and beside the packaged tables at
gpuwm_data/data/thompson/LICENSE-WRF.txt, byte-identical to WRF's own
(md5 ea0d72123846bafa972b29ca41f89b1a) and carrying the "WRF(R) is a
registered trademark" line as UCAR writes it.

An earlier version of this file said WRF was "released by UCAR as open
source per its own notice". That was wrong in both halves -- WRF is not
open source and UCAR's notice does not say it is -- and it is withdrawn.

What this distribution packages from WRF: the Thompson microphysics
lookup tables under gpuwm_data/data/thompson/tables/, generated with WRF's
own table generator and SHA-256-pinned by
gpuwm/core/thompson_contract.py in the companion package.

UCAR's declaration disclaims UCAR's own claims. It cannot dispose of
anyone else's, and one other claim reaches these tables; see "Numerical
Recipes Software" below.

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Numerical Recipes Software

The Thompson tables here are the OUTPUT of WRF's table generator, and that
generator computes gamma functions with WRF's REAL FUNCTION GAMMLN, which
phys/module_mp_thompson.F brackets with "(C) Copr. 1986-92 Numerical
Recipes Software 2.02" immediately above and below.

No Numerical Recipes code is in this distribution -- these are binary
tables of numbers, not source -- so what is reproduced here is the notice
and ArWen's position on it, not a licence over the bytes. Both are at
licenses/NOTICE-Numerical-Recipes.txt, unchanged from the copy in the
gpuwm distribution, where the transcription those tables came from lives.
It is reproduced here because a table's provenance does not stop at the
program that wrote it, and because a reader who finds the notice in one
distribution should not have to guess whether it was meant to apply to the
other.

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RTE+RRTMGP

The k-distribution and cloud-optics files under gpuwm_data/data/rrtmgp/
come from the earth-system-radiation rrtmgp-data repository and are BSD
3-Clause, "Copyright (c) 2015-2018, Atmospheric and Environmental Research
and Regents of the University of Colorado". That text ships beside the
data at gpuwm_data/data/rrtmgp/LICENSE and again at
licenses/LICENSE-RTE-RRTMGP-BSD-3-Clause.txt. Per-file upstream URLs, tag,
commit and SHA-256 are in gpuwm_data/data/rrtmgp/PROVENANCE.md.

The software that reads them -- about 5,700 lines under gpuwm/core/ -- is
a different work with a different copyright line and is covered by the
gpuwm distribution's NOTICE, not by this one.

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Reference results under non-commercial terms

The RFMIP clear-sky reference results
(rfmip-clear-sky-reference-{lw,sw}-{up,down}.nc) are CC-BY-NC-SA-4.0:
NonCommercial and ShareAlike, which is incompatible with Apache-2.0. They
are excluded from BOTH built artifacts -- from the wheel by
exclude-package-data and from the source distribution by the same entry,
which setuptools applies to both -- so a `pip install gpuwm-data` never
receives them. They remain in the public git repository as a verification
fixture; the Apache-2.0 grant in the LICENSE file does not extend to them
and is not offered over them. Their licence text ships at
gpuwm_data/data/rrtmgp/LICENSE-CC-BY-NC-SA-4.0 so that PROVENANCE.md
resolves.

The related rfmip-clear-sky-inputs.nc carries an internal attribute naming
CC-BY-4.0 and a link to CC-BY-SA-4.0. The ambiguity is recorded in
PROVENANCE.md and both texts ship beside the file rather than one being
chosen for the reader.

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Two entries this file used to carry, and why they are gone

  * RRTMG (AER). This distribution said "RRTMG was developed by
    Atmospheric and Environmental Research, Inc. (AER); its code and data
    carry AER's copyright and license notices, which are retained with the
    assets." Two things were wrong. RRTMG_LW_DATA and RRTMG_SW_DATA are
    unformatted Fortran binaries that carry no notice, so nothing was
    being retained; and they are not in this distribution at all -- they
    ship in the gpuwm wheel under gpuwm/data/wrf_radiation/, where AER's
    notice and BSD-3-Clause grant are now reproduced beside them.
  * Vendored Rust crates, wrf-rust, and the data-services paragraph. This
    distribution vendors no crates, links no Rust, downloads nothing and
    renders nothing. Those paragraphs were copied from the gpuwm NOTICE
    and described that distribution, not this one.
