Ouranosinc/xclim v0.27.0

on GitHub

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.