Xclim

--------------------
Contributors to this version: Juliette Lavoie (:user:`juliettelavoie`).

Bug fixes
^^^^^^^^^
* Add ``measure`` to YAML validation schema (for building sdba properties) and allow skipping the YAML validation when building modules. (:pull:`1664`).

--------------------
Contributors to this version: Trevor James Smith (:user:`Zeitsperre`).

Bug fixes
^^^^^^^^^
* Fixed an issue with missing `conda` dependencies in the `xclim` documentation. (:pull:`1657`).
* Adjusted the Mastodon publishing workflow. (:pull:`1657`).
* Pinned `nbconvert` to address regressions when building the documentation. (:pull:`1658`).

--------------------
Contributors to this version: Juliette Lavoie (:user:`juliettelavoie`), Pascal Bourgault (:user:`aulemahal`), Trevor James Smith (:user:`Zeitsperre`), David Huard (:user:`huard`), Éric Dupuis (:user:`coxipi`), Dante Castro (:user:`profesorpaiche`), Gabriel Rondeau-Genesse (:user:`RondeauG`).

Announcements
^^^^^^^^^^^^^
* `xclim` no longer supports Python3.8. (:issue:`1268`, :pull:`1565`).
* `xclim` now officially supports Python3.12 (requires `numba>=0.59.0`). (:pull:`1613`).
* `xclim` now adheres to the `Semantic Versioning 2.0.0 <https://semver.org/>`_ specification. (:issue:`1556`, :pull:`1569`).
* The `xclim` repository now uses `GitHub Discussions <https://github.com/Ouranosinc/xclim/discussions>`_ to offer help for users, coordinate translation efforts, and support general Q&A for the `xclim` community. The `xclim` `Gitter` room has been deprecated in favour of GitHub Discussions. (:issue:`1571`, :pull:`1572`).
* For secure correspondence, `xclim` now offers a PGP key for users to encrypt sensitive communications. For more information, see the ``SECURITY.md``. (:issue:`1181`, :pull:`1604`).

New features and enhancements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* Added uncertainty partitioning method `lafferty_sriver` from Lafferty and Sriver (2023), which can partition uncertainty related to the downscaling method. (:issue:`1497`, :pull:`1529`).
* Validate YAML indicators description before trying to build module. (:issue:`1523`, :issue:`1595`, :pull:`1560`, :pull:`1596`, :pull:`1600`).
* Support ``indexer`` keyword in YAML indicator description. (:issue:`1522`, :pull:`1561`).
* New ``xclim.core.calendar.stack_periods`` and ``unstack_periods`` for performing ``rolling(time=...).construct(..., stride=...)`` but with non-uniform temporal periods like years or months. They replace ``xclim.sdba.processing.construct_moving_yearly_window`` and ``unpack_moving_yearly_window`` which are deprecated and will be removed in a future release.
* New ``as_dataset`` options for ``xclim.set_options``. When True, indicators will output Datasets instead of DataArrays. (:issue:`1257`, :pull:`1625`).
* Added new option for ``universal_thermal_climate_index`` calculation (``wind_cap_min: bool``) to cap low wind velocities to a minimum of 0.5 m/s following Bröde (2012) guidelines. (:issue:`1634`, :pull:`1635`).
* Added option ``never_reached`` to ``degree_days_exceedance_date`` to assign a custom value when the sum threshold is never reached. (:issue:`1459`, :pull:`1647`).
* Added option ``min_members`` to ensemble statistics to mask elements when the number of valid members is under a threshold. (:issue:`1459`, :pull:`1647`).
* Distribution instances can now be passed to the ``dist`` argument of most statistical indices. (:pull:`1644`).
* Added a new ``xclim.indices.generic.select_rolling_resample_op`` function to allow for computing rolling statistics. (:issue:`1480`, :pull:`1643`).
* Add the possibility to use a group with a window in ``xc.sdba.processing.reordering``. (:pull:`1566`).

Breaking changes
^^^^^^^^^^^^^^^^
* `xclim` base Python version has been raised to Python3.9. Python3.9+ coding conventions are now supported. (:issue:`1268`, :pull:`1565`).
* `xclim` base dependencies have been raised to `pandas>=2.2.0` and `xarray>=2023.11.0` to reflect changes to time frequency codes introduced in `pandas==2.2.0`. (:issue:`1534`, :pull:`1565`; see also: `pydata/xarray GH/8394 <https://github.com/pydata/xarray/issues/8394>`_ and ). Many default frequency string outputs have been modified (:
* 'Y' (year) -> 'YE' (year end). (see: `pandas PR/55792 <https://github.com/pandas-dev/pandas/pull/55792>`_).
* 'M' (month) -> 'ME' (month end). (see: `pandas PR/52064 <https://github.com/pandas-dev/pandas/pull/52064>`_).
* 'Q' (quarter) -> 'QE' (quarter end). (see: `pandas PR/55553 <https://github.com/pandas-dev/pandas/pull/55553>`_)
* 'A' and 'AS' have been removed (use 'YE' and 'YS' instead). (see: `pandas PR/55252 <https://github.com/pandas-dev/pandas/pull/55252>`_). ('YE' is only supported for cftime data in `xarray >= 2024.1.1`).
* 'T' (minute), 'L' (millisecond), 'U' (microsecond), and 'N' (nanosecond) -> 'min', 'ms', 'us', and 'ns'. (see: `pandas PR/54061 <https://github.com/pandas-dev/pandas/pull/54061>`_).
* `bump2version` has been replaced with `bump-my-version` to bump the version number using configurations set in the ``pyproject.toml`` file. (:issue:`1557`, :pull:`1569`).
* `xclim`'s units registry and units formatting are now extended from `cf-xarray`. The exponent sign "^" is now never added in the ``units`` attribute. For example, square meters are given as "m2" instead of "m^2" by `xclim`. Both signs are still accepted as inputs. (:issue:`1010`, :pull:`1590`).
* `yamale` is now listed as a core dependency (was previously listed in the `dev` installation recipe). (:issue:`1595`, :pull:`1596`).
* Due to a licensing limitation, the calculation of empirical orthogonal function based on `eofs` (``xclim.sdba.properties.first_eof``) has been removed from `xclim`. (:issue:`1620`, :pull:`1621`).
* `black` formatting style has been updated to the 2024 stable conventions. `isort` has been added to the `dev` installation recipe. (:pull:`1626`).
* The indice and indicator for ``winter_storm`` has been removed (deprecated since `xclim>=0.46.0` in favour of ``snd_storm_days``). (:pull:`1565`).
* `xclim` has dropped support for `scipy` versions below v1.9.0 and `numpy` versions below v1.20.0. (:pull:`1565`).
* For generic function ``select_resample_op`` and ``core.units.to_agg_units``, operation "sum" will now return the same units as the input, and not implicitly be translated to an "integral". (:issue:`1645`, :pull:`1649`).
* `lmoments3` was removed as a dependency of `xclim` due to incompatible licensing (GPLv3 vs `xclim`'s Apache 2.0). Depending on the outcome of efforts to modify the licensing of `lmoments3`, this change may eventually be reverted. See `Ouranosinc/lmoments312 <https://github.com/Ouranosinc/lmoments3/issues/12>`_. See also the "frequency analysis" notebook for an example on how to continue using the probability weighted moments method for fitting distributions. (:issue:`1620`, :pull:`1644`).

Bug fixes
^^^^^^^^^
* Fixed passing ``missing=0`` to ``xclim.core.calendar.convert_calendar``. (:issue:`1562`, :pull:`1563`).
* Fixed wrong `window` attributes in ``xclim.indices.standardized_precipitation_index``, ``xclim.indices.standardized_precipitation_evapotranspiration_index``. (:issue:`1552` :pull:`1554`).
* Fixed the daily case ``freq='D'`` for ``xclim.stats.preprocess_standardized_index`` (:issue:`1602` :pull:`1607`).
* Several spelling mistakes have been corrected within the documentation and codebase. (:pull:`1576`).
* Added missing ``xclim.ensembles.robustness_fractions`` and ``xclim.ensembles.robustness_categories`` in API doc section. (:pull:`1630`).
* Fixed an issue that can occur when fetching the testing data and running tests on Windows systems. Adapted a few existing tests for Windows support. (:pull:`1648`).

Internal changes
^^^^^^^^^^^^^^^^
* The `flake8` configuration has been migrated from ``setup.cfg`` to ``.flake8``; ``setup.cfg`` has been removed. (:pull:`1569`)
* The ``bump-version.yml`` workflow has been adjusted to bump the `patch` version when the last version is determined to have been a `release` version; otherwise, the `build` version is bumped. (:issue:`1557`, :pull:`1569`).
* The GitHub Workflows now use the `step-security/harden-runner` action to monitor source code, actions, and dependency safety. All workflows now employ more constrained permissions rule sets to prevent security issues. (:pull:`1577`, :pull:`1578`, :pull:`1597`).
* Updated the ``CONTRIBUTING.rst`` directions to showcase the new versioning system. (:issue:`1557`, :pull:`1573`).
* The `codespell` library is now a development dependency for the `dev` installation recipe with configurations found within ``pyproject.toml``. This is also now a linting step and integrated as a `pre-commit` hook. For more information, see the `codespell documentation <https://github.com/codespell-project/codespell>`_ (:pull:`1576`).
* Climate indicators search page now prioritizes the "official" indicators (atmos, land, seaIce and generic), virtual submodules can be added to search through checkbox option. (:issue:`1559`, :pull:`1593`).
* The OpenSSF StepSecurity bot has contributed some changes to the workflows and pre-commit. (:issue:`1181`, :pull:`1606`):
* Dependabot has been configured to monitor the `xclim` repository for dependency updates. The ``actions-version-updater.yml`` workflow has been deprecated.
* GitHub Actions are now pinned to their commit hashes to prevent unexpected changes in the future.
* A new GitHub Workflow (``workflow-warning.yml``) has been added to warn maintainers when a forked repository has been used to open a Pull Request that modifies GitHub Workflows.
* `pylint` has been configured to provide some overhead checks of the `xclim` codebase as well as run as part of `xclim`'s `pre-commit` hooks.
* Some small adjustments to code organization to address `pylint` errors.
* `dev` formatting tools (`black`, `blackdoc`, `isort`) are now pinned to their `pre-commit` hook version equivalents in both ``pyproject.toml`` and ``tox.ini``. (:pull:`1626`).
* `black`, `isort`, and `pyupgrade` code formatters no longer target Python3.8 coding style conventions. (:pull:`1565`).
* The GitHub Workflows now include builds to run tests against both Windows and MacOS. (:pull:`1648`).
* `prefetch` is now available as a `tox` environment modifier in order to download the testing data before launching `pytest` (e.g. `py3x-prefetch`). This is required for running tests the first time on Windows if the testing data has not already been installed. (:pull:`1648`).
* Removed `step-security/harden-runner` from the `finish` job as it does not work on container images lacking `sudo` access. (:pull:`1655`).

--------------------
Contributors to this version: Juliette Lavoie (:user:`juliettelavoie`), Pascal Bourgault (:user:`aulemahal`), Trevor James Smith (:user:`Zeitsperre`), David Huard (:user:`huard`), Éric Dupuis (:user:`coxipi`).

Announcements
^^^^^^^^^^^^^
* To circumvent issues stemming from changes to the frequency code convention in `pandas` v2.2, we have pinned `xarray` (< 2023.11.0) and `pandas` (< 2.2) for this release. This change will be reverted in `xclim` v0.48.0 to support the newer versions. (`xarray>= 2023.11.0` and `pandas>= 2.2`).
* `xclim` v0.47.0 will be the last release supporting Python3.8.

New features and enhancements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* New functions ``xclim.ensembles.robustness_fractions`` and ``xclim.ensembles.robustness_categories``. The former will replace ``xclim.ensembles.change_significance`` which is now deprecated and will be removed in `xclim` v0.49.0. (:pull:`1514`).
* Added indicator ID to searched terms in the indicator search documentation page. (:issue:`1525`, :pull:`1528`).

Bug fixes
^^^^^^^^^
* Fixed a bug with ``n_escore=-1`` in ``xclim.sdba.adjustment.NpdfTransform``. (:issue:`1515`, :pull:`1516`).
* In the documentation, fixed the tooltips in the indicator search results. (:issue:`1524`, :pull:`1527`).
* If chunked inputs are passed to indicators ``mean_radiant_temperature`` and ``potential_evapotranspiration``, sub-calculations of the solar angle will also use the same chunks, instead of a single one of the same size as the data. (:issue:`1536`, :pull:`1542`).
* Fix wrong attributes in ``xclim.indices.standardized_precipitation_index``, ``xclim.indices.standardized_precipitation_evapotranspiration_index``. (:issue:`1537`, :pull:`1538`).

Internal changes
^^^^^^^^^^^^^^^^
* Pinned `cf-xarray` below v0.8.5 in Python3.8 installation to further extend legacy support. (:pull:`1519`).
* `pip check` in conda builds in GitHub workflows have been temporarily set to always pass. (:pull:`1531`).
* Configure RtD search rankings to emphasize notebooks and indicators over indices and raw source code. (:pull:`1526`).
* Addressed around 100 very basic `mypy` typing errors and call signature errors. (:pull:`1532`).
* Use the intermediate step ``_cumsum_reset_on_zero`` instead of ``rle`` which is sufficient in ``_boundary_run``. (:issue:`1405`, :pull:`1530`).

--------------------
Contributors to this version: David Huard (:user:`huard`), Trevor James Smith (:user:`Zeitsperre`), Pascal Bourgault (:user:`aulemahal`), Éric Dupuis (:user:`coxipi`).

Announcements
^^^^^^^^^^^^^
* The default mechanism for computing the Mean Radiant Temperature, a part of the Universal Thermal Climate Index (UTCI) was broken in xclim v0.44.0 and v0.45.0. This has now been fixed by changing the default settings.

New indicators
^^^^^^^^^^^^^^
* ``xclim.indices.snw_storm_days`` computes the number of days with snowfall amount accumulation above a given threshold (default: `10 Kg m-2`). (:pull:`1505`).
* Added ``xclim.indices.wind_power_potential`` to estimate the potential for wind power production given wind speed at the turbine hub height and turbine specifications, along with ``xclim.indices.wind_profile`` to estimate the wind speed at different heights based on wind speed at a reference height. (:issue:`1458`, :pull:`1471`).

New features and enhancements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* `xclim` now has a dedicated console command for prefetching testing data from `xclim-testdata` with branch options (e.g.: `$ xclim prefetch_testing_data --branch some_development_branch`). This command can be used to download the testing data to a local cache, which can then be used to run the testing suite without internet access or in "offline" mode. For more information, see the contributing documentation section for `Updating Testing Data`. (:issue:`1468`, :pull:`1473`).
* The testing suite now offers a means of running tests in "offline" mode (using `pytest-socket <https://github.com/miketheman/pytest-socket>`_ to block external connections). This requires a local copy of `xclim-testdata` to be present in the user's home cache directory and for certain `pytest` options and markers to be set when invoked. For more information, see the contributing documentation section for `Running Tests in Offline Mode`. (:issue:`1468`, :pull:`1473`).
* The `SKIP_NOTEBOOKS` flag to speed up docs builds is now documented. See the contributing documentation section `Get Started!` for details. (:issue:`1470`, :pull:`1476`).
* Refactored the indicators page with the addition of a search bar (:issue:`1433`, :pull:`1454`).
* Indicator ``xclim.indices.generic.stats`` now accepts any frequency (previously only `daily`). (:pull:`1498`).
* Added argument `"out_units"` to ``select_resample_op`` to bypass limitations of ``to_agg_units`` in custom indicators. Also, added ``var`` to supported operations in ``to_agg_units``. (:pull:`1498`).
* `adapt_freq_thresh` argument was added `to `sdba`` training functions, to facilitate performing frequency adaptation appropriately in each map block. (:pull:`1407`).
* Standardized indices (``xclim.indices.standardized_precipitation_index`` and ``xclim.indices.standardized_precipitation_evapotranspiration_index``) (:issue:`1270`, :issue:`1416`, :issue:`1474`, :pull:`1311`) were changed:
* Optimized and noticeably faster calculation.
* Can be computed in two steps: first compute fit parameters with ``xclim.indices.stats.standardized_index_fit_params``, then use the output in the standardized indices functions.
* The standardized index values are now clipped to ±8.21. This reflects the ``float64`` precision of the computation when cumulative distributed function values are inverted to a normal distribution and avoids returning infinite values.
* An offset parameter is now available to account for negative water balance values``xclim.indices.standardized_precipitation_evapotranspiration_index``.

Bug fixes
^^^^^^^^^
* Fixed an error in the `pytest` configuration that prevented copying of testing data to thread-safe caches of workers under certain conditions (this should always occur). (:pull:`1473`).
* Coincidentally, this also fixes an error that caused `pytest` to error-out when invoked without an active internet connection. Running `pytest` without network access is now supported (requires cached testing data). (:issue:`1468`).
* Calling a ``sdba.map_blocks``-wrapped function with data chunked along the reduced dimensions will raise an error. This forbids chunking the trained dataset along the distribution dimensions, for example. (:issue:`1481`, :pull:`1482`).
* Optimization of indicators ``huglin_index`` and ``biologically_effective_degree_days`` when used with `dask` and `flox`. As a side effect, the indice functions (i.e. under ``xclim.indices``) no longer mask incomplete periods. The indicators' output is unchanged under the default `"check_missing"` setting (:issue:`1494`, :pull:`1495`).
* Fixed ``xclim.indices.run_length.lazy_indexing`` which would sometimes trigger the loading of auxiliary coordinates. (:issue:`1483`, :pull:`1484`).
* Indicators ``snd_season_length`` and ``snw_season_length`` will return `0` instead of `NaN` if all inputs have a (non-`NaN`) zero snow depth (or water-equivalent thickness). (:pull:`1492`, :issue:`1491`)
* Fixed a bug in the `pytest` configuration that could prevent testing data caching from occurring in systems where the platform-dependent cache directory is not found in the user's home. (:issue:`1468`, :pull:`1473`).
* Fix ``xclim.core.dataflags.data_flags`` variable name generation (:pull:`1507`).
* Remove nonsensical `stat='average'` option for ``mean_radiant_temperature``. (:issue:`1496`, :pull:`1501`).

Breaking changes
^^^^^^^^^^^^^^^^
* `pytest-socket` is now a required development dependency for running `"offline"` tests or the `"offline"` configuration of the `tox` testing suite. This has been added to the `dev` installation recipe. (:issue:`1468`, :pull:`1473`).
* For better transparency and control in development, the `tox` configuration has been adapted to allow passing of markers directly to the `pytest` call. Positional arguments must be passed to tox after the `--` separator to select/deselect tests (e.g. ``'tox -e py38 -- -m "not slow"'``). (:pull:`1473`).
* For better accuracy, the `tox -e black` recipe has been renamed to `tox -e lint`, as this configuration already included several other linting checks. (:pull:`1473`).
* ``xclim.indices.winter_storm`` renamed to ``xclim.indices.snd_storm_days``. (:pull:`1505`).
* Default threshold in ``xclim.indices.snw_season_{start|length|end}`` changed form `20 kg m-2` to `4 kg m-2`. (:pull:`1505`).
* `xclim` development dependencies now include `ruff`. `pycodestyle` and `pydocstyle` have been replaced by `ruff` and removed from the `dev` installation recipe. (:pull:`1504`).
* The `mf_file` call signature found in ``xclim.ensembles.create_ensemble`` (and ``xclim.ensembles._ens_align_dataset``) has been removed (deprecated since `xclim` v0.43.0). (:pull:`1506`).
* ``xclim.indices.standardized_precipitation_index`` and ``xclim.indices.standardized_precipitation_evapotranspiration_index`` will no longer accept two datasets (data and calibration data). Instead, a single dataset covering both the calibration and evaluation periods is expected. (:issue:`1270`, :pull:`1311`).

Internal changes
^^^^^^^^^^^^^^^^
* Changed "degK" to "K" (used to designate Kelvin units). (:pull:`1475`).
* Added a `pytest` marker (``pytest.mark.requires_internet``) to allow for skipping of tests that depend on remote network calls to function properly. (:pull:`1473`).
* Added handling for `pytest-socket`'s ``SocketBlockedError`` in ``xclim.testing.open_dataset`` when attempting to fetch md5 validation files for cached testing data while explicitly disabling internet sockets. (:issue:`1468`, :pull:`1473`).
* Updated the testing data used in the `analogs.ipynb` notebook to use the testing data now found in `Ouranosinc/xclim-testdata`'s main branch. (`xclim-testdata PR/26 <https://github.com/Ouranosinc/xclim-testdata/pull/26>`_, :pull:`1473`).
* Fixed an issue with automatic labelling that occurs when a Pull Request is made from a forked repository. (:pull:`1479`).
* Changes to the ``.zenodo.json`` file no longer are marked as CI-related changes. (:pull:`1479`).
* GitHub deployment workflows now employs use of deployment environments for workflow security and uses the `Trusted Publisher <https://docs.pypi.org/trusted-publishers/using-a-publisher/>`_ feature to sign and publish the `xclim` wheel and source distributions. (:pull:`1469`).
* Mastodon publishing now uses `chuhlomin/render-template <https://github.com/chuhlomin/render-template>`_ and a standard formatting markdown document to format Mastodon toots. (:pull:`1469`).
* GitHub testing workflows now use `Concurrency` instead of the styfle/cancel-workflow-action to cancel redundant workflows. (:pull:`1487`).
* The `pkg_resources` library has been replaced for the `packaging` library when version comparisons have been performed, and a few warning messages have been silenced in the testing suite. (:issue:`1489`, :pull:`1490`).
* New ``xclim.testing.helpers.assert_lazy`` context manager to assert the laziness of code blocks. (:pull:`1484`).
* Added a fix for the deprecation warnings that `importlib.resources` throws, made backwards-compatible for Python3.8 with `importlib_resources` backport. (:pull:`1485`).
* Added basic keywords on most indicators for easier searching in the docs. Extracted climate indicators API to its own page for faster loading. (:pull:`1502`, :issue:`1433`).
* `nbstripout` now removes 'metadata.kernelspec' in notebook cells. (:pull:`1407`).
* Deprecation wrapper ``xclim.core.utils.deprecated`` are added to help with deprecation warnings. (:pull:`1505`).
* `xclim` now uses `ruff` to format the codebase with `make lint` and `pre-commit`. `flake8` is still used for the time being, solely to enforce docstring linting (with `flake8-rst-docstrings`) and alphabetical `__all__` entries (with `flake8-alphabetize`). (:pull:`1504`).

--------------------
Contributors to this version: David Huard (:user:`huard`), Trevor James Smith (:user:`Zeitsperre`), Pascal Bourgault (:user:`aulemahal`), Juliette Lavoie (:user:`juliettelavoie`), Gabriel Rondeau-Genesse (:user:`RondeauG`), Marco Braun (:user:`vindelico`), Éric Dupuis (:user:`coxipi`).

Announcements
^^^^^^^^^^^^^
* `xclim` now uses `platformdirs` to write `xclim-testdata` to the user's cache directory. Dynamic paths are now used to cache data dependent on the user's operating system. Developers can now safely delete the ``.xclim-testdata`` folder in their home directory without affecting the functionality of `xclim`. (:pull:`1460`).

New indicators
^^^^^^^^^^^^^^
* Variations of already existing indices: ``xclim.indices.snd_max`` and ``xclim.indices.frost_free_spell_max_length``. (:pull:`1443`, :issue:`1386`).

New features and enhancements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
* Added ``ensembles.hawkins_sutton`` method to partition the uncertainty sources in a climate projection ensemble. (:issue:`771`, :pull:`1262`), along with a notebook example. (:pull:`1466`).
* New function ``xclim.core.calendar.convert_doy`` to transform day-of-year data between calendars. Also accessible from ``convert_calendar`` with ``doy=True``. (:issue:`1283`, :pull:`1406`).
* New ``xclim.units.declare_relative_units`` to enable relative unit checks. This was applied to most "generic" indices. (:pull:`1414`).
* Added new function ``xclim.sdba.properties.std`` to calculate the standard deviation of a variable over all years at a given time resolution. (:pull:`1445`).
* Amended the documentation of ``xclim.sdba.properties.trend`` to document already existing functionality of calculating the return values of ``scipy.stats.linregress``. (:pull:`1445`).
* Add support for setting optional variables through the ``ds`` argument. (:issue:`1432`, :pull:`1435`).
* New ``xclim.core.calendar.is_offset_divisor`` to test if a given freq divides another one evenly (:pull:`1446`).
* Missing value objects now support input timeseries of quarterly and yearly frequencies (:pull:`1446`).
* Missing value checks enabled for all "generic" indicators (``return_level``, ``fit`` and ``stats``) (:pull:`1446`).

Bug fixes
^^^^^^^^^
* Fix ``kldiv`` docstring so the math formula renders to HTML. (:issue:`1408`, :pull:`1409`).
* Fix the registry entries of "generic" indicators. (:issue:`1423`, :pull:`1424`).
* Fix ``jetstream_metric_woollings`` so it uses the ``vertical`` coordinate identified by `cf-xarray`, instead of ``pressure`` (:issue:`1421`, :pull:`1422`).
* Add logic to handle coordinates in decreasing order, or for longitudes defined from 0-360 instead of -180 to 180. (:issue:`1429`, :pull:`1430`).
* Fix virtual indicator attribute assignment causing individual indicator's realm to be ignored. (:issue:`1425`, :pull:`1426`).
* Fixes the ``raise_flags`` argument of ``xclim.core.dataflags.data_flags`` so that an `Exception` is only raised when some checkups fail. (:issue:`1456`, :pull:`1457`).
* Fix ``xclim.indices.generic.get_zones`` so that `bins` can be given as input without error. (:pull:`1455`).

Internal changes
^^^^^^^^^^^^^^^^
* Tolerance thresholds for error in ``test_stats::test_fit`` have been relaxed to allow for more variation in the results. Previously untested ``*_moving_yearly_window`` functions are now tested. (:issue:`1400`, :pull:`1402`).
* Increased the guess of number of quantiles needed in `ExtremeValues`. (:pull:`1413`).
* Tolerance thresholds for error in ``test_processing::test_adapt_freq`` have been relaxed to allow for more variation in the results. (:issue:`1417`, :pull:`1418`).
* Added ``"streamflow"`` to the list of known variables. (:pull:`1431`).
* Refactoring of index backend calculations. (:pull:`1443`, :issue:`1386`):
* Use ``xclim.indices.generic.select_resample_op`` for ``{tg|tn|tx}_{max|mean|min}`` , ``max_1day_precipitation_amount``, ``{snw|snd}_max``
* Directly use ``{cold|hot}_spell_max_length`` in ``maximum_consecutive_{frost|tx}_days``
* ``xclim.indices.generic.select_resample_op`` now gives an output with the correct units (``xclim.core.units.to_agg_units`` is used internally).
* Shuffle autogenerated documentation files into distinct folders that can be easily cleaned using Makefile. (:pull:`1449`).
* Some docstring adjustments to existing classes. (:pull:`1449`).
* The `pre-commit` dependency `identify` now associates Jupyter Notebooks as JSON files. `pre-commit` is now set to ignore JSON-formatting of notebooks. (:pull:`1449`).
* Added a helper module ``_finder`` in the notebooks folder so that the working directory can always be found, with redundancies in place to prevent scripts from failing if the helper file is not found. (:pull:`1449`).
* Added a manual cache-cleaning workflow (based on `GitHub cache-cleaning example <https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows#managing-caches>`_), triggered when a branch has been merged. (:pull:`1462`).
* Added a workflow for posting updates to the xclim Mastodon account (using `cbrgm/mastodon-github-action <https://github.com/cbrgm/mastodon-github-action>`_, triggered when a new version is published. (:pull:`1462`).
* Refactor base indicator classes and fix misleading inheritance of ``return_level``. (:issue:`1263`, :pull:`1446`).

Breaking changes
^^^^^^^^^^^^^^^^
* Fix and adapt ``percentile_doy`` for an error raised by xarray > 2023.7.0. (:issue:`1417`, :pull:`1450`).
* `integral` replaces `prod` and `delta_prod` as possible input in ``xclim.core.units.to_agg_units`` (:pull:`1443`, :issue:`1386`).