v0.32.0

Contributors to this version: Pascal Bourgault (@aulemahal), Travis Logan (@tlogan2000), Trevor James Smith (@Zeitsperre), Abel Aoun (@bzah), David Huard (@huard), Clair Barnes (@clairbarnes), Raquel Alegre (@raquel-ucl), Jamie Quinn (@JamieJQuinn), Maliko Tanguy (@malngu), Aaron Spring (@aaronspring).

Announcements

• Code coverage (coverage/coveralls) is now a required CI check for merging Pull Requests. Requirements are now:
  • No individual run may report <80% code coverage.
  • Some drop in coverage is now tolerable, but runs cannot dip below -0.25% relative to the main branch.

New features and enhancements

• Added an optimized pathway for xclim.indices.run_length functions when window=1. (PR/911, GH/910).
• The data input frequency expected by Indicator is now in the src_freq attribute and is thus controllable by subclassing existing indicators. (GH/898, PR/927).
• New **indexer keyword args added to many indicators, it accepts the same arguments as xclim.indices.generic.select_time, which has been improved. Unless otherwise specified, the time selection is done before any computation. (PR/934, GH/899).
• Rewrite of xclim.sdba.ExtremeValues, now fixed with a correct algorithm. It has not been tested extensively and should be considered experimental. (PR/914, GH/789, GH/790).
• Added days_over_precip_doy_thresh and fraction_over_precip_doy_thresh indicators to distinguish between WMO and ECAD definition of the Rxxp and RxxpTot indices. (GH/931, PR/940).
• Update xclim.core.utils.nan_calc_percentiles to improve maintainability. (PR/942).
• Added heat_index indicator. Added heat_index indicator. This is similar to humidex but uses a different dew point as well as heat balance equations which account for variables other than vapor pressure. (GH/807) and (PR/915).
• Added alternative method for xclim.indices.potential_evapotranspiration based on mcguinnessbordne05 (from Tanguay et al. 2018). (PR/926, GH/925).
• Added snw_max and snw_max_doy indicators to compute the maximum snow amount and the day of year of the maximum snow amount respectively. (GH/776, PR/950).
• Added index for calculating ratio of convective to total precipitation. (GH/920, PR/921).
• Added wetdays_prop indicator to calculate the proportion of days in a period where the precipitation is greater than a threshold. (PR/919, GH/918).

Breaking changes

• Following version 1.9 of the CF Conventions, published in September 2021, the calendar name "gregorian" is deprecated. core.calendar.get_calendar will return "standard", even if the underlying cftime objects still use "gregorian" (cftime <= 1.5.1). (PR/935).
• xclim.sdba.utils.extrapolate_qm is now deprecated and will be removed in version 0.33. ([PR/941](https://github.com/Ourano
• Dependency pint minimum necessary version is now 0.10. (PR/959).
  sinc/xclim/pull/941)).

Internal changes

• Removed some logging configurations in xclim.core.dataflags that were polluting python's main logging configuration. (PR/909).
• Synchronized logging formatters in xclim.ensembles and xclim.core.utils. (PR/909).
• Added a helper function for generating the release notes with dynamically-generated ReStructuredText or Markdown-formatted hyperlinks (PR/922, GH/907).
• Split of resampling-related functionality of Indicator into new ResamplingIndicator and ResamplingIndicatorWithIndexing subclasses. The use of new (private) methods makes it easier to inject functionality in indicator subclasses. (GH/867, PR/927, PR/934).
• French translation metadata fields are now cleaner and much more internally consistent, and many empty metadata fields (e.g. comment_fr) have been removed. (PR/930, GH/929).
• Adjustments to the tox builds so that slow tests are now run alongside standard tests (for more accurate coverage reporting). (PR/938).
• Use xarray.apply_ufunc to vectorize statistical functions. (PR/943).
• Refactor of xclim.sdba.utils.interp_on_quantiles so that it now handles the extrapolation directly and to better handle missing values. (PR/941).
• Updated heating_degree_days and fraction_over_precip_thresh documentations. (GH/952, PR/953).
• Added an intersphinx mapping to xarray. (PR/955).
• Added a CodeQL security analysis GitHub CI hook on push to master and on Friday nights. (PR/960).

Bug fixes

• Fix bugs in the cf_attrs and/or abstract of continuous_snow_cover_end and continuous_snow_cover_start. (PR/908).
• Remove unnecessary keep_attrs from resample call which would raise an error in futur Xarray version. (PR/937).
• Fixed a bug in the regex that parses usernames in the history. (PR/945).
• Fixed a bug in xclim.indices.generic.doymax and xclim.indices.generic.doymin that prevented the use of the functions on multidimensional data. (PR/950, GH/951).
• Skip all missing values in xclim.sdba.utils.interp_on_quantiles, drop them from both the old and new coordinates, as well as from the old values. (PR/941).
• "degrees_north" and "degrees_east" (and their variants) are now considered independent units, so that pint and xclim.core.units.ensure_cf_units don't convert them to "deg". (PR/959).
• Fixed a bug in xclim.core.dataflags that would misidentify the "extra" variable to be called when running multivariate checks. (PR/957, GH/861).

v0.31.0

Contributors to this version: Abel Aoun (@bzah), Pascal Bourgault (@aulemahal), David Huard (@huard), Juliette Lavoie (@juliettelavoie), Travis Logan (@tlogan2000), Trevor James Smith (@Zeitsperre).

New indicators

• thawing_degree_days indicator returns degree-days above a default of thresh="0 degC". (PR/895, GH/887).
• freezing_degree_days indicator returns degree-days below a default of thresh="0 degC". (PR/895, GH/887).
• Several frost-free season calculations are now available as both indices and indicators. (PR/895, GH/887):
  • frost_free_season_start
  • frost_free_season_end
  • frost_free_season_length
• growing_season_start is now offered as an indice and as an indicator to complement other growing season-based indicators (threshold calculation with op=">="). (PR/895, GH/887).

New features and enhancements

• Improve cell_methods checking to search the wanted method within the whole string. (PR/866, GH/863).
• New align_on='random option for xclim.core.calendar.convert_calendar, for conversions involving '360_day' calendars. (PR/875, GH/841).
• dry_spell_frequency now has a parameter op: {"sum", "max"} to choose if the threshold is compared against the accumulated or maximal precipitation, over the given window. (PR/879).
• maximum_consecutive_frost_free_days is now checking that the minimum temperature is above or equal to the threshold ( instead of only above). (PR/883, GH/881).
• The ANUCLIM virtual module has been updated to accept weekly and monthly inputs and with improved metadata. (PR/885, GH/538)
• The sdba.loess algorithm has been optimized to run faster in all cases, with an even faster special case (equal_spacing=True) when the x coordinate is equally spaced. When activated, this special case might return results different from without, up to around 0.1%. (PR/865).
• Add support for group's window and additional dimensions in LoessDetrend. Add new RollingMeanDetrend object. (PR/865).
• Missing value algorithms now try to infer the source timestep of the input data when it is not given. (PR/885).
• On indices, bootstrap parameter documentation has been updated to explain when and why it should be used. (PR/893, GH/846).

Breaking changes

• Major changes in the YAML schema for virtual submodules, now closer to how indicators are declared dynamically, see the doc for details. (PR/849, GH/848).
• Removed xclim.generic.daily_downsampler, as it served no purpose now that xarray's resampling works with cftime (PR/888, GH/889).
• Refactor of xclim.core.calendar.parse_offset, output types were changed to useful ones (PR/885).
• Major changes on how parameters are passed to indicators. (PR/873):
  • Their signature is now consistent : input variables (DataArrays, optional or not) are positional or keyword arguments and all other parameters are keyword only. (GH/855, GH/857)
  • Some indicators have modified signatures because we now rename variables when wrapping generic indices. This is the case for the whole cf module, for example.
  • Indicator.parameters is now a property generated from Indicator._all_parameters, as the latter includes the injected parameters. The keys of the former are instances of new xclim.core.indicator.Parameter, and not dictionaries as before.
  • New Indicator.injected_parameters to see which compute function arguments will be injected at call time.
  • See the pull request (PR/873) for all information.
• The call signature for huglin_index has been modified to reflect the correct variables used in its formula (tasmin -> tas; thresh_tasmin -> thresh). (PR/903, GH/902).

Internal changes

• Pull Request contributions now require hyperlinks to the issue and pull request pages on GitHub listed alongside changess in HISTORY.rst. (PR/860,GH/854).
• Updated the contribution guidelines to better give credit to contributors and more easily track changes. (PR/869, GH/868).
• Enabled coveralls code coverage reporting for GitHub CI. (PR/870).
• Added automated TestPyPI and PyPI-publishing workflows for GitHub CI. (PR/872).
• Changes on how indicators are constructed. (PR/873).
• Added missing algorithms tests for conversion from hourly to daily. (PR/888).
• Updated pre-commit hooks to use black v21.10.b0. (PR/896).
• Moved stack_variables, unstack_variables, construct_moving_yearly_window and unpack_moving_yearly_window from xclim.sdba.base to xclim.sdba.processing. They still are imported in xclim.sdba as before. (PR/892).
• Many improvements to the documentation. (PR/892, GH/880).
• Added regex replacement handling in setup.py to facilitate publishing contributor/contribution links on PyPI. (PR/906).

Bug fixes

• Fix a bug in bootstrapping where computation would fail when the dataset time coordinate is encoded using cftime.datetime. (PR/859).
• Fix a bug in build_indicator_module_from_yaml where bases classes (Daily, Hourly, etc) were not usable with the base field. (PR/885).
• percentile_doy alpha and beta parameters are now properly transmitted to bootstrap calls of this function. (PR/893, GH/846).
• When called with a 1D da and ND index, xclim.indices.run_length.lazy_indexing now drops the auxiliary coordinate corresponding to da's index. This fixes a bug with ND data in xclim.indices.run_length.season. (PR/900).
• Fix name of heating degree days in French ("chauffe" -> "chauffage"). (PR/895).
• Corrected several French indicator translation description strings (bad usages of "." in description and long_name fields). (PR/895).
• Fixed an error with the formula for huglin_index where tasmin was being used in the calculation instead of tas. (PR/903, GH/902).

v0.30.1

Bug fixes

• Fix a bug in xclim.sdba's map_groups where 1D input including an auxiliary coordinate would fail with an obscure error on a reducing operation.

v0.30.0

New indicators

• climatological_mean_doy indice returns the mean and standard deviation across a climatology according to day-of-year (xarray.DataArray.groupby("time.dayofyear")). A moving window averaging of days can also be supplied (default:window=1).
• within_bnds_doy indice returns a boolean array indicating whether or not array's values are within bounds for each day of the year.
• Added atmos.wet_precip_accumulation, an indicator accumulating precipitation over wet days.
• Module ICCLIM now includes PRCPTOT, which accumulates precipitation for days with precipitation above 1 mm/day.

New features and enhancements

• xclim.core.utils.nan_calc_percentiles now uses a custom algorithm instead of numpy.nanpercentiles to have more flexibility on the interpolation method. The performance is also improved.

• xclim.core.calendar.percentile_doy now uses the 8th method of Hyndman & Fan for linear interpolation (alpha = beta = 1/3). Previously, the function used Numpy's percentile, which corresponds to the 7th method. This change is motivated by the fact that the 8th is recommended by Hyndman & Fay, and it ensures consistency with other climate indices packages (climdex, icclim). Using alpha = beta = 1 restores the previous behaviour.

• xclim.core.utils._cal_perc is now only a proxy for xc.core.utils.nan_calc_percentiles with some axis moves.

• xclim now implements many data quality assurance flags (xclim.core.dataflags) for temperature and precipitation based on ICCLIM documentation guidelines <https://eca.knmi.nl/documents/atbd.pdf>_. These checks include the following:

  • Temperature (variables: tas, tasmin, tasmax): tasmax_below_tasmin, tas_exceeds_tasmax, tas_below_tasmin, temperature_extremely_low (thresh="-90 degC"), temperature_extremely_high (thresh="60 degC").
  • Precipitation-specific (variables: pr, prsn, ): negative_accumulation_values, very_large_precipitation_events (thresh="300 mm d-1").
  • Wind-specific (variables: sfcWind, wsgsmax/sfcWindMax): wind_values_outside_of_bounds
  • Generic: outside_n_standard_deviations_of_climatology, values_repeating_for_n_or_more_days, values_op_thresh_repeating_for_n_or_more_days, percentage_values_outside_of_bounds.

  These quality-assurance checks are selected according to CF-standard variable names, and can be triggered via xclim.core.dataflags.data_flags(xarray.DataArray, xarray.Dataset). These checks are separate from the Indicator-defined datachecks and must be launched manually. They'll return an array of data_flags as boolean variables.
  If called with raise_flags=True, will raise an Exception with comments for each quality control check raised.

• A convenience function (xclim.core.dataflags.ecad_compliant) is also offered as a method for asserting that data adheres to all relevant ECAD/ICCLIM checks. For more information on usage, consult the docstring/documentation.

• A new utility "dataflags" is also available for performing fast quality control checks from the command-line (xclim dataflags --help). See the CLI documentation page for usage examples.

• Added missing typed call signatures, expected returns and docstrings for many xclim.core.calendar functions.

Breaking changes

• All "ANUCLIM" indices and indicators have lost their src_timestep argument. Most of them were not using it and now every function infers the frequency from the data directly. This may add stricter constraints on the time coordinate, the same as for xarray.infer_freq.
• Many functions found within xclim.core.cfchecks (generate_cfcheck and check_valid_*) have been removed as existing indicator CF-standard checks and data checks rendered them redundant/obsolete.

Bug fixes

• Fixes in sdba for (1) inputs with dimensions without coordinates, for (2) sdba.detrending.MeanDetrend and for (3) DetrendedQuantileMapping when used with dask's distributed scheduler.
• Replaced instances of '◦' ("White bullet") with '°' ("Degree Sign") in icclim.yaml as it was causing issues for non-UTF8 environments.
• Addressed an edge case where test_sdba::test_standardize randomness could generate values that surpass the test error tolerance.
• Added a missing .txt file to the MANIFEST of the source distributable in order to be able to run all tests.
• xc.core.units.rate2amount is now exact when the sampling frequency is monthly, seasonal or yearly. Earlier, monthly and yearly data were computed using constant month and year length. End-of-period frequencies are also correctly understood (ex: "M" vs "MS").
• In the potential_evapotranspiration indice, add abbreviated method names to docstring.
• Fixed an issue that prevented using the default group arg in adjustment objects.
• Fix bug in missing_wmo, where a period would be considered valid if all months met WMO criteria, but complete months in a year were missing. Now, if any month does not meet criteria or is absent, the period will be considered missing.
• Fix bootstrapping with dask arrays. Dask does not support using loc with multiple indexes to set new values, so a workaround was necessary.
• Fix bootstrapping when the bootstrapped year must be converted to a 366_day calendar.
• Virtual modules and translations now use 'UTF-8' by default when reading yaml or json file, instead of a machine-dependent encoding.

Internal Changes

• xclim code quality checks now use the newest black (v21.8-beta). Checks launched via tox and pre-commit now run formatting modifications over Jupyter notebooks found under docs.

v0.29.0

Announcements

• It was found that the ExtremeValues adjustment algorithm was not as accurate and stable as first thought. It is now hidden from xclim.sdba but can still be accessed via xclim.sdba.adjustment, with a warning. Work on improving the algorithm is ongoing, and a better implementation will be in a future version.
• It was found that the add_dims argument of sdba.Grouper had some caveats throughout sdba. This argument is to be used with care before a careful analysis and more testing is done within xclim.

Breaking changes

• xclim has switched back to updating the history attribute (instead of xclim_history). This impacts all indicators, most ensemble functions, percentile_doy and sdba.processing (see below).
• Refactor of sdba.processing. Now all functions take one or more dataarrays as input, plus some parameters. And output one or more dataarrays (not Datasets). Units and metadata is handled. This impacts sdba.processing.adapt_freq especially.
• Add unit handling in sdba. Most parameters involving quantities are now expecting strings (and not numbers). Adjustment objects will ensure ref, hist and sim all have the same units (taking ref as reference).
• The Adjustment` classes of xclim.sdba have been refactored into 2 categories:
  • TrainAdjust objects (most of the algorithms), which are created and trained in the same call:
    obj = Adj.train(ref, hist, **kwargs). The .adjust step stays the same.
  • Adjust objects (only NpdfTransform), which are never initialized. Their adjust
    class method performs all the work in one call.
• snowfall_approximation used a "<" condition instead of "<=" to determine the snow fraction based on the freezing point temperature. The new version sticks to the convention used in the Canadian Land Surface Scheme (CLASS).
• Removed the "gis", "docs", "test" and "setup"extra dependencies from setup.py. The dev recipe now includes all tools needed for xclim's development.

New features and enhancements

• snowfall_approximation has gained support for new estimation methods used in CLASS: 'brown' and 'auer'.
• A ValidationError will be raised if temperature units are given as 'deg C', which is misinterpreted by pint.
• Functions computing run lengths (sequences of consecutive "True" values) now take the index argument. Possible values are first and last, indicating which item in the run should be used to index the run length. The default is set to "first", preserving the current behavior.
• New sdba_encode_cf option to workaround a cftime/xarray performance issue when using dask.

New indicators

• effective_growing_degree_days indice returns growing degree days using dynamic start and end dates for the growing season (based on Bootsma et al. (2005)). This has also been wrapped as an indicator.
• qian_weighted_mean_average (based on Qian et al. (2010)) is offered as an alternate method for determining the start date using a weighted 5-day average (method="qian"). Can also be used directly as an indice.
• cold_and_dry_days indicator returns the number of days where the mean daily temperature is below the 25th percentile and the mean daily precipitation is below the 25th percentile over period. Added as CD indicator to ICCLIM module.
• warm_and_dry_days indicator returns the number of days where the mean daily temperature is above the 75th percentile and the mean daily precipitation is below the 25th percentile over period. Added as WD indicator to ICCLIM module.
• warm_and_wet_days indicator returns the number of days where the mean daily temperature is above the 75th percentile and the mean daily precipitation is above the 75th percentile over period. Added as WW indicator to ICCLIM module.
• cold_and_wet_days indicator returns the number of days where the mean daily temperature is below the 25th percentile and the mean daily precipitation is above the 75th percentile over period. Added as CW indicator to ICCLIM module.
• calm_days indicator returns the number of days where surface wind speed is below threshold.
• windy_days indicator returns the number of days where surface wind speed is above threshold.

Bug fixes

• Various bug fixes in bootstrapping:
  • in percentile_bootstrap decorator, fix the popping of bootstrap argument to propagate in to the function call.
  • in bootstrap_func, fix some issues with the resampling frequency which was not working when anchored.
• Made argument thresh of sdba.LOCI required, as not giving it raised an error. Made defaults explicit in the adjustments docstrings.
• Fixes in sdba.processing.adapt_freq and sdba.nbutils.vecquantiles when handling all-nan slices.
• Dimensions in a grouper's add_dims are now taken into consideration in function wrapped with map_blocks/groups. This feature is still not fully tested throughout sdba though, so use with caution.
• Better dtype preservation throughout sdba.
• "constant" extrapolation in the quantile mappings' adjustment is now padding values just above and under the target's max and min, instead of ±np.inf.
• Fixes in sdba.LOCI for the case where a grouping with additionnal dimensions is used.

Internal Changes

• The behaviour of xclim.testing._utils.getfile was adjusted to launch file download requests for web-hosted md5 files for every call to compare against local test data.
  This was done to validate that locally-stored test data is identical to test data available online, without resorting to git-based actions. This approach may eventually be revised/optimized in the future.

v0.28.1

Announcements

• The xclim binary package available on conda-forge will no longer supply clisops by default. Installation of clisops must be performed explicitly to preserve subsetting capabilities.

New indicators

• snow_depth indicator returns the mean snow depth over period. Added as SD to ICCLIM module.

Internal Changes

• Minor modifications to many function call signatures (type hinting) and docstrings (numpy docstring compliance).

v0.28.0

New features and enhancements

• Automatic load of translations on import and possibility to pass translations for virtual modules.
• New xclim.testing.list_datasets function listing all available test datasets in repo xclim-testdata.
• spatial_analogs accepts multi-indexes as the dist_dim parameter and will work with candidates and target arrays of different lengths.
• humidex can be computed using relative humidity instead of dewpoint temperature.
• New sdba.construct_moving_yearly_window and sdba.unpack_moving_yearly_window for moving window adjustments.
• New sdba.adjustment.NpdfTransform which is an adaptation of Alex Cannon's version of Pitié's N-dimensional probability density function transform. Uses new sdba.utils.rand_rot_matrix. Experimental, subject to changes.
• New sdba.processing.standardize, .unstandardize and .reordering. All of them, tools needed to replicate Cannon's MBCn algorithm.
• New sdba.processing.escore, backed by sdba.nbutils._escore to evaluate the performance of the N pdf transform.
• New function xclim.indices.clausius_clapeyron_scaled_precipitation can be used to scale precipitation according to changes in mean temperature.
• Percentile based indices gained a bootstrap argument that applies a bootstrapping algorithm to reduce biases on exceedance frequencies computed over in base and out of base periods. Experimental, subject to changes.
• Added a .zenodo.json file for collecting and maintaining author order and tracking ORCIDs.

Bug fixes

• Various bug fixes in sdba :

  • in QDM.adjust, fix bug occuring with coords of 'object' dtype and interp='nearest'.
  • in nbutils.quantiles, fix dtype bug when using float32 data.
  • raise a proper error when ref and hist have a different calendar for map_blocks-backed adjustments.

Breaking changes

• spatial_analogs does not support sequence of dist_dim anymore. Users are responsible for stacking dimensions prior to calling spatial_analogs.

New indicators

• biologically_effective_degree_days (with method="gladstones") indice computes degree-days between two specific dates, with a capped daily max value as well as latitude and temperature range swing as modifying coefficients (based on Gladstones, J. (1992)). This has also been wrapped as an indicator.

• An alternative implementation of biologically_effective_degree_days (with method="icclim", based on ICCLIM formula) ignores latitude and temperature range swing modifiers and uses an alternate end_date. Wrapped and available as an ICCLIM indicator.

• cool_night_index indice returns the mean minimum temperature in September (lat >= 0 deg N) or March (lat < 0 deg N), based on Tonietto & Carbonneau, 2004 (10.1016/j.agrformet.2003.06.001). Also available as an indicator (see indices Notes section on indicator usage recommendations).

• latitude_temperature_index indice computes LTI values based on mean temperature of warmest month and a parameterizable latitude coefficient (default: lat_factor=75) based on Jackson & Cherry, 1988, and Kenny & Shao, 1992 (10.1080/00221589.1992.11516243). This has also been wrapped as an indicator.

• huglin_index indice computes Huglin Heliothermal Index (HI) values based on growing degrees and a latitude-influenced coefficient for day-length (based on Huglin. (1978)). The indice supports several methods of estimating the latitude coefficient:

  • method="smoothed": Marks latitudes between -40 N and 40 N with k=1, and linearly increases to k=1.06 at |lat|==50.
  • method="icclim": Uses a stepwise function based on the the original method as presented by Huglin (1978). Identical to the ICCLIM implementation.
  • method="jones": Uses a more robust calculation for calculating day-lengths, based on Hall & Jones (2010). This method is now also available for biologically_effective_degree_days.

• The generic indice day_length, used for calculating approximate daily day-length in hours per day or, given start_date and end_date, the total aggregated day-hours over period. Uses axial tilt, start and end dates, calendar, and approximate date of northern hemisphere summer solstice, based on Hall & Jones (2010).

Internal Changes

• aggregate_between_dates (introduced in v0.27.0) now accepts DayOfYear-like strings for supplying start and end dates (e.g. start="02-01", end="10-31").
• The indicator call sequence now considers "variable" the inputs annoted so. Dropped the nvar attribute.
• Default cfcheck is now to check metadata according to the variable name, using CMIP6 names in xclim/data/variable.yml.
• Indicator.missing defaults to "skip" if freq is absent from the list of parameters.
• Minor modifications to the GitHub Pull Requests template.
• Simplification of some yaml elements for virtual modules.
• Allow injecting freq without the missing checks failing.

v0.27.0

New features and enhancements

• Rewrite of nearly all adjustment methods in sdba, with use of xr.map_blocks to improve scalability with dask. Rewrite of some parts of the algorithms with numba-accelerated code.
• "GFWED" specifics for fire weather computation implemented back into the FWI module. Outputs are within 3% of GFWED data.
• Addition of the run_length_ufunc option to control which run length algorithm gets run. Defaults stay the same (automatic switch dependent of the input array : the 1D version is used with non-dask arrays with less than 9000 points per slice).
• Indicator modules built from YAML can now use custom indices. A mapping or module of them can be given to build_indicator_module_from_yaml with the indices keyword.
• Virtual submodules now include an iter_indicators function to iterate over the pairs of names and indicator objects in that module.
• The indicator string formatter now accepts a "r" modifier which passes the raw strings instead of the adjective version.
• Addition of the sdba_extra_output option to adds extra diagnostic variables to the outputs of Adjustment objects. Implementation of sim_q in QuantileDeltaMapping and nclusters in ExtremeValues.

Breaking changes

• The tropical_nights indice is being deprecated in favour of tn_days_above with thresh="20 degC". The indicator remains valid, now wrapping this new indice.

• Results of sdba.Grouper.apply for Groupers without a group (ex: Grouper('time')) will contain a group singleton dimension.

• The daily_freezethaw_cycles indice is being deprecated in favour of multiday_temperature_swing`` with temp thresholds at 0 degC and window=1, op="sum"`. The indicator remains valid, now wrapping this new indice.

• CMIP6 variable names have been adopted whenever possible in xclim. Changes are:

  • swe is now snw (snw is the snow amount [kg / m²] and swe the liquid water equivalent thickness [m])
  • rh is now hurs
  • dtas is now tdps
  • ws (in FWI) is now sfcWind
  • sic is now siconc
  • area (of sea ice indicators) is now areacello
  • Indicators RH and RH_FROMDEWPOINT have be renamed to HURS and HURS_FROMDEWPOINT. These are changes in the identifiers, the python names (relative_humidity[...]) are unchanged.

New indicators

• atmos.corn_heat_units computes the daily temperature-based index for corn growth.
• New indices and indicators for tx_days_below, tg_days_above, tg_days_below, and tn_days_above.
• atmos.humidex returns the Canadian humidex, an indicator of perceived temperature account for relative humidity.
• multiday_temperature_swing indice for returning general statistics based on spells of doubly-thresholded temperatures (Tmin < T1, Tmax > T2).
• New indicators atmos.freezethaw_frequency, atmos.freezethaw_spell_mean_length, atmos.freezethaw_spell_max_length for statistics of Tmin < 0 degC and Tmax > 0 deg C days now available (wrapped from multiday_temperature_swing).
• atmos.wind_chill_index computes the daily wind chill index. The default is similar to what Environment and Climate Change Canada does, options are tunable to get the version of the National Weather Service.

Internal Changes

• run_length.rle_statistics now accepts a window argument.
• Common arguments to the op parameter now have better adjective and noun formattings.
• Added and adjusted typing in call signatures and docstrings, with grammar fixes, for many xclim.indices operations.

v0.26.1 (May the fourth be with you)

Bug fixes

• Bug fix release adding ExtremeValues to publicly exposed bias-adjustment methods.

v0.26.0

Announcements

• xclim no longer supports Python3.6. Code conventions and new features from Python3.7 (PEP 537) are now accepted.

New features and enhancements

• core.calendar.doy_to_days_since and days_since_to_doy to allow meaningful statistics on doy data.
• New bias second-order adjustment method "ExtremeValues", intended for re-adjusting extreme precipitation values.
• Virtual indicators modules can now be built from YAML files.
• Indicators can now be built from dictionaries.
• New generic indices, implementation of clix-meta's index functions.
• On-the-fly generation of climate and forecasting convention (CF) checks with xc.core.cfchecks.generate_cfcheck, for a few known variables only.
• New xc.indices.run_length.rle_statistics for min, max, mean, std (etc) statistics on run lengths.
• New virtual submodule cf, with CF standard indices defined in clix-meta.
• Indices returning day-of-year data add two new attributes to the output: is_dayofyear (=1) and calendar.

Breaking changes

• xclim now requires xarray>=0.17.
• Virtual submodules icclim and anuclim are not available at the top level anymore (only through xclim.indicators).
• Virtual submodules icclim and anuclim now provide Indicators and not indices.
• Spatial analog methods "KLDIV" and "Nearest Neighbor" now require scipy>=1.6.0.

Bug fixes

• from_string object creation in sdba has been removed. Now replaced with use of a new dependency, jsonpickle.

Internal Changes

• pre-commit linting checks now run formatting hook black==21.4b2.
• Code cleaning (more accurate call signatures, more use of https links, docstring updates, and typo fixes).