Ouranosinc/xclim: 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.