v0.24.0

New indicators

• days_over_precip_thresh, fraction_over_precip_thresh, liquid_precip_ratio, warm_spell_duration_index, all from eponymous indices.
• maximum_consecutive_warm_days from indice maximum_consecutive_tx_days.

Breaking changes

• Numerous changes to xclim.core.calendar.percentile_doy:

  • per now accepts a sequence as well as a scalar and as such the output has a percentiles axis.
  • per argument is now expected to between 0-100 (not 0-1).
  • input data must have a daily (or coarser) time frequency.

• Change in unit handling paradigm for indices, which as a result will lead to some indices returning values with different units. Note that related Indicator objects remain unchanged and will return units consistent with CF Convention. If you are concerned with code stability, please use Indicator objects. The change was necessary to resolve inconsistencies with xarray's keep_attrs=True context.

  • Indice functions now return output units that preserve consistency with input units. That is, feeding inputs in Celsius will yield outputs in Celsius instead of casting to Kelvin. In all cases the dimensionality is preserved.
  • Indice functions now accept non-daily data, but daily frequency is assumed by default if the frequency cannot be inferred.

• Removed the explicitly-installed netCDF4 python library from the base installation, as this is never explicitly used (now only installed in the docs recipe for sdba documented example).

• Removed xclim.core.checks, which was deprecated since v0.18.

New features and enhancements

• Indicator now have docstrings generated from their metadata.
• Units and fixed choices set are parsed from indice docstrings into Indicator.parameters.
• Units of indices using the declare_units decorator are stored in indice.in_units and indice.out_units.
• Changes to Indicator.format and Indicator.json to ensure the resulting json really is serializable.

Internal changes

• Leave missing_options undefined in land.fit indicator to allow control via set_options.
• Modified xclim.core.calendar.percentile_doy to improve performance.
• New xclim.core.calendar.compare_offsets for comparing offset strings.
• New xclim.indices.generic.get_op to retrieve a function from a string representation of that operator.
• The CI pipeline has been migrated from Travis CI to GitHub Actions. All stages are still built using tox.
• Indice functions must always set the units (the declare_units decorator does no check anymore).
• New xclim.core.units.rate2amout to convert rates like precipitation to amounts.
• xclim.core.units.pint2cfunits now removes ' * ' symbols and changes Δ° to delta_deg.
• New xclim.core.units.to_agg_units and xclim.core.units.infer_sampling_units for unit handling involving aggregation operations along the time dimension.
• Added an indicators API page to the docs and links to there from the Climate Indicators page.

Bug fixes

• The unit handling change resolved a bug that prevented the use of xr.set_options(keep_attrs=True) with indices.

v0.23.0

Breaking changes

• Renamed indicator atmos.degree_days_depassment_date to atmos.degree_days_exceedance_date.
• In degree_days_exceedance_date : renamed argument start_date to after_date.
• Added cfchecks for Pr+Tas-based indicators.
• Refactored test suite to now be available as part of the standard library installation (xclim.testing.tests).
• Running pytest with xdoctest now requires the rootdir to point at tests location (pytest --rootdir xclim/testing/tests/ --xdoctest xclim).
• Development checks now require working jupyter notebooks (assessed via the pytest --nbval command).

New indicators

• rain_approximation and snowfall_approximation for computing prlp and prsn from pr and tas (or tasmin or tasmax) according to some threshold and method.
• solid_precip_accumulation and liquid_precip_accumulation now accept a thresh parameter to control the binary snow/rain temperature threshold.
• first_snowfall and last_snowfall to compute the date of first/last snowfall exceeding a threshold in a period.

New features and enhancements

• New kind entry in the parameters property of indicators, differentiating between [optional] variables and parameters.
• The git pre-commit hooks (pre-commit run --all) now clean the jupyter notebooks with nbstripout call.

Bug fixes

• Fixed a bug in indices.run_length.lazy_indexing that occurred with 1D coords and 0D indexes when using the dask backend.
• Fixed a bug with default frequency handling affecting fit indicator.
• Set missing method to 'skip' for freq_analysis indicator.
• Fixed a bug in ensembles._ens_align_datasets that occurred when inputs are .nc filepaths but files lack a time dimension.

Internal changes

• core.cfchecks.check_valid now accepts a sequence of strings as its expected argument.
• Clean up in the tests to speed up testing. Addition of a marker to include "slow" tests when desired (-m slow).
• Fixes in the tests to support sklearn>=0.24, clisops>=0.5 and build xarray@master against python 3.7.
• Moved the testing suite to within xclim and simplified tox to manage its own tempdir.
• Indicator class now has a default_freq method.

v0.22.0

Breaking changes

• Statistical functions (frequency_analysis, fa, fit, parametric_quantile) are now solely accessible via indices.stats.

New indicators

• atmos.degree_days_depassment_date, the day of year when the degree days sum exceeds a threshold.

New features and enhancements

• Added unique titles to atmos calculations employing wrapped_partials.
• xclim.core.calendar.convert_calendar now accepts a missing argument.
• Added xclim.core.calendar.date_range and xclim.core.calendar.date_range_like wrapping pandas' date_range and xarray's cftime_range.
• xclim.core.calendar.get_calendar now accepts many different types of data, including datetime object directly.
• New module xclim.analog and method xclim.analog.spatial_analogs to compute spatial analogs.
• Indicators can now accept dataset in their new ds call argument. Variable arguments (that use the DataArray annotation) can now be given with strings that correspond to variable names in the dataset, and default to their own name.
• Clarification to frequency_analysis notebook.
• Now officially supporting PEP596 (Python3.9).
• New methods xclim.ensembles.change_significance and xclim.ensembles.knutti_sedlacek to qualify climate change agreement among members of an ensemble.

Bug fixes

• Fixed bug that prevented the use of xclim.core.missing.MissingBase and subclasses with an indexer and a cftime datetime coordinate.
• Fixed issues with metadata handling in statistical indices.
• Various small fixes to the documentation (re-establishment of some internally and externally linked documents).

Internal changes

• Passing align_on to xclim.core.calendar.convert_calendar without using '360_day' calendars will not raise a warning anymore.
• Added formatting utilities for metadata attributes (update_cell_methods, prefix_attrs and unprefix_attrs).
• xclim/ensembles.py moved to xclim/ensembles/*.py, splitting stats/creation, reduction and robustness methods.
• With the help of the mypy library, added several typing fixes to better identify inputs/outputs, and reduce object type mutations.
• Fixed some doctests in ensembles and set_options.
• clisops v0.4.0+ is now an optional requirements for non-Windows builds.
• New xclim.core.units.str2pint method to convert quantity strings to quantity objects. Main improvement is to make "3 degC days" a valid string that converts to "3 K days".

v0.21.0

Breaking changes

• Statistical functions (frequency_analysis, fa, fit, parametric_quantile) moved from indices.generic to indices.stats to make them more visible.

New features and enhancements

• New xclim.testing.open_dataset method to read data from the remote testdata repo.
• Added a notebook, ensembles-advanced.ipynb, to the documentation detailing ensemble reduction techniques and showing how to make use of built-in figure-generating commands.
• Added a notebook, frequency_analysis.ipynb, with examples showcasing frequency analysis capabilities.

Bug fixes

• Fixed a bug in the attributes of frost_season_length.
• indices.run_length methods using dates now respect the array's calendar.
• Worked around an xarray bug in sdba.QuantileDeltaMapping when multidimensional arrays are used with linear or cubic interpolation.

v0.20.0

Breaking changes

• xclim.subset has been deprecated and now relies on clisops to perform specialized spatio-temporal subsetting.
  Install with pip install xclim[gis] in order to retain the same functionality.
• The python library pandoc is no longer listed as a docs build requirement. Documentation still requires a current
  version of pandoc binaries installed at system-level.
• ANUCLIM indices have seen their input_freq parameter renamed to src_timestep for clarity.
• A clean-up and harmonization of the indicators metadata has changed some of the indicator identifiers, long_names, abstracts and titles. xclim.atmos.drought_code and fire_weather_indexes now have indentifiers "dc" and "fwi" (lowercase version of the previous identifiers).
• xc.indices.run_length.run_length_with_dates becomes xc.indices.run_length.season_length. Its argument date is now optional and the default changes from "07-01" to None.
• xc.indices.consecutive_frost_days becomes xc.indices.maximum_consecutive_frost_days.
• Changed the history indicator output attribute to xclim_history in order to respect CF conventions.

New indicators

• atmos.max_pr_intensity acting on hourly data.
• atmos.wind_vector_from_speed, also the wind_speed_from_vector now also returns the "wind from direction".
• Richards-Baker flow flashiness indicator (xclim.land.rb_flashiness_index).
• atmos.max_daily_temperature_range.
• atmos.cold_spell_frequency.
• atmos.tg_min and atmos.tg_max.
• atmos.frost_season_length, atmos.first_day_above. Also, atmos.consecutive_frost_days now takes a thresh argument (default : 0 degC).

New features and enhancements

• sdba.loess submodule implementing LOESS smoothing tools used in sdba.detrending.LoessDetrend.
• xclim now depends on clisops for subsetting, offloading several heavy GIS dependencies. This improves
  maintainability and reduces the size of a "vanilla" xclim installation considerably.
• New generic.parametric_quantile function taking parameters estimated by generic.fit as an input.
• Add support for using probability weighted moments method in generic.fit function. Requires the
  lmoments3 package, which is not included in dependencies because it is unmaintained. Install manually if needed.
• Implemented _fit_start utility function providing initial conditions for statistical distribution parameters estimation, reducing the likelihood of poor fits.
• Added support for indicators based on hourly (1H) inputs, and a first hourly indicator called max_pr_intensity
  returning hourly precipitation intensity.
• Indicator instances can be retrieved through their class with the get_instance() class method.
  This allows the use of xclim.core.indicator.registry as an instance registry.
• Indicators now have a realm attribute. It must be given when creating indicators outside xclim.
• Better docstring parsing for indicators: parameters description, annotation and default value are accessible in the json output and Indicator.parameters.
• New command line interface xclim for simple indicator computing tasks.
• New sdba.processing.jitter_over_thresh for variables with a upper bound.
• Added op parameter to xclim.indices.daily_temperature_range to allow resample reduce operations other than mean
• core.formatting.AttrFormatter (and thus, locale dictionaries) can now use glob-like pattern for matching values to translate.

Bug fixes

• The ICCLIM module was identified as icclim in the documentation but the module available under ICCLIM. Now icclim == ICCLIM and ICCLIM will be deprecated in a future release.

Internal changes

• xclim.subset now attempts to load and expose the functions of clisops.core.subset. This is an API workaround preserving backwards compatibility.
• Code styling now conforms to the latest release of black (v0.20.8).
• New IndicatorRegistrar class that takes care of adding indicator classes and instances to the
  appropriate registries. Indicator now inherits from it.

v0.19.0

Breaking changes

• Refactoring of the Indicator class. The cfprobe method has been renamed to cfcheck and the validate
  method has been renamed to datacheck. More importantly, instantiating Indicator creates a new subclass on
  the fly and stores it in a registry, allowing users to subclass existing indicators easily. The algorithm for
  missing values is identified by its registered name, e.g. "any", "pct", etc, along with its missing_options.
• xclim now requires xarray >= 0.16, ensuring that xclim.sdba is fully functional.
• The dev requirements now include xdoctest -- a rewrite of the standard library module, doctest.
• xclim.core.locales.get_local_attrs now uses the indicator's class name instead of the indicator itself and no
  longer accepts the fill_missing keyword. Behaviour is now the same as passing False.
• Indicator.cf_attrs is now a list of dictionaries. Indicator.json puts all the metadata attributes in the key "outputs" (a list of dicts).
  All variable metadata (names in Indicator._cf_names) might be strings or lists of strings when accessed as object attributes.
• Passing doctests are now strictly enforced as a build requirement in the Travis CI testing ensemble.

New features and enhancements

• New ensembles.kkz_reduce_ensemble method to select subsets of an ensemble based on the KKZ algorithm.
• Create new Indicator Daily, Daily2D subclasses for indicators using daily input data.
• The Indicator class now supports outputing multiple indices for the same inputs.
• xclim.core.units.declare_units now works with indices outputting multiple DataArrays.
• Doctests now make use of the xdoctest_namespace in order to more easily access mdoules and tesdata.

Bug fixes

• Fix generic.fit dimension ordering. This caused errors when "time" was not the first dimension in a DataArray.

Internal changes

• datachecks.check_daily now uses xr.infer_freq.
• Indicator subclasses Tas, Tasmin, Tasmax, Pr and Streamflow now inherit from Daily.
• Indicator subclasses TasminTasmax and PrTas now inherit from Daily2D.
• Docstring style now enforced using the pydocstyle with numpy doctsring conventions.
• Doctests are now performed for all docstring Examples using xdoctest. Failing examples must be explicitly skipped otherwise build will now fail.
• Indicator methods update_attrs and format are now classmethods, attrs to update must be passed.
• Indicators definitions without an accompanying translation (presently French) will cause build failures.
• Major refactoring of the internal marchinery of Indicator to support multiple outputs.

v0.18.0

0.18.x (2020-06-26)

• Optimization options for xclim.sdba : different grouping for the normalization steps of DQM and save training or fitting datasets to temporary files.
• xclim.sdba.detrending objects can now act on groups.
• Replaced dask[complete] with dask[array] in basic installation and added distributed to docs build dependencies.
• xclim.core.locales now supported in Windows build environments.
• ensembles.ensemble_percentiles modified to compute along a percentiles dimension by default, instead of creating different variables.
• Added indicator first_day_below and run length helper first_run_after_date.
• Added ANUCLIM model climate indices mappings.
• Renamed areacella to areacello in sea ice tests.
• Sea ice extent and area outputs now have units of m2 to comply with CF-Convention.
• Split checks.py into cfchecks.py, datachecks.py and missing.py. This change will only affect users creating custom indices using utilities previously located in checks.py.
• Changed signature of daily_freeze_thaw_cycles, daily_temperature_range, daily_temperature_range_variability and extreme_temperature_range to take (tasmin, tasmax) instead of (tasmax, tasmin) and match signature of other similar multivariate indices.
• Added FromContext subclass of MissingBase to have a uniform API for missing value operations.
• Remove logging commands that captured all xclim warnings. Remove deprecated xr.set_options calls.

v0.17.0

0.17.x (2020-05-15)

• Added support for operations on dimensionless variables (units = '1')
• Moved xclim.locales to xclim.core.locales in a batch of internal changes aimed to removed most potential cyclic imports cases.
• Missing checks and input validation refactored with addition of custom missing class registration (xclim.core.checks.register_missing_method) and simple validation method decorator (xclim.core.checks.check).
• New xclim.set_options context to control the missing checks, input validation and locales.
• New xclim.sdba module for statistical downscaling and bias-adjustment of climate data.
• Added convert_calendar and interp_calendar to help in the conversion between calendars.
• Added at_least_n_valid function, indentifying null calculations based on minimum threshold.
• Added support for freq=None in missing calculations.
• Fixed outdated code examples in the docs and docstrings.
• Doctests are now run as part of the test suite.

v0.16.0

0.16.0 (2020-04-23)

• Added vectorize flag to subset_shape and create_mask_vectorize function based on shapely.vectorize as default backend for mask creation.
• Removed start_yr and end_yr flags from subsetting functions.
• Add multi gridpoints support in subset.subset_gridpoint.
• Better wrapped_partial for more meaningful inspection.
• Add indices for relative humidity, specific humidity and saturation vapor pressure with a few choices of method.
• Allow lazy units conversion.
• CRS definitions of projected DataSets are now written to file according to Climate and Forecast-convention standards.
• Add utilities to merge attributes and update history in xclim.core.formatting.
• Ensembles : Allow alignment of datasets with same frequency but different offsets.
• Bug fixes in run_length for run-with-dates methods when the date is not found in the run.
• Remove deepcopy from subset.subset_shape to improve memory usage.
• Add missing_wmo function, identifying null calculations based on criteria from WMO.
• Add missing_pct function, identifying null calculations based on percentage of missing values.

v0.15.0

0.15.x (2020-03-12)

• Improvement in FWI: Vectorization of DC, DMC and FFMC with numba and small code refactoring for better maintainability.
• Added example notebook for creating a catalog of selected indices
• Added growing_season_end, last_spring_frost, dry_days, hot_spell_frequency, hot_spell_max_length, and maximum_consecutive_frost_free_days indices.
• Dropped use of fiona.crs class in lieu of the newer pyproj CRS handler for subset_shape operations.
• Completed first phase of internal reorganization of xclim.
• Internationalization of xclim : add locales submodule for localized metadata.
• Add feature to retrieve coordinate values instead of index in run_length.first_run. Add run_length.last_run.
• Fix bug in subset_gridpoint to work on lat/lon coords of any dimension when they are not a dimension of the data.