earthkit.climate.atmos.temperature.huglin_index

earthkit.climate.atmos.temperature.huglin_index(tas: xarray.DataArray | str = 'tas', tasmax: xarray.DataArray | str = 'tasmax', lat: xarray.DataArray | str = 'lat', ds: xarray.Dataset | Any = None, *, thresh: Any = '10 degC', method: str = 'jones', cap_value: float = 1.0, start_date: str | str = '04-01', end_date: str | str = '10-01', freq: Literal['YS', 'YS-JAN', 'YS-JUL'] = 'YS', **kwargs: Any) → Any

Huglin heliothermal index.

Heat-summation index for agroclimatic suitability estimation, developed specifically for viticulture. Considers daily minimum and maximum temperature with a given base threshold, typically between 1 April and 30September, and integrates a day-length coefficient calculation for higher latitudes. Metric originally published in Huglin (1978). Day-length coefficient based on Hall & Jones (2010).

Units:

  • hi: dimensionless

This function wraps xclim.indicators.atmos.huglin_index.

Parameters:

  • tas (xarray.DataArray | str) – Mean daily temperature.

  • tasmax (xarray.DataArray | str) – Maximum daily temperature.

  • lat (xarray.DataArray | str) – Latitude coordinate. If None, a CF-conformant “latitude” field must be available within the passed DataArray.

  • thresh (Any) – The temperature threshold.

  • method (str) – The formula to use for the latitude coefficient calculation. The “huglin” method uses a stepwise latitude coefficient for values between 40° and 50° based on :cite:t:`huglin_nouveau_1978`. The “interpolated” method uses a smoothed curve latitude coefficient for values based on the intervals set in :cite:t:`huglin_nouveau_1978`. The “jones” method integrates axial tilt, latitude, and day-of-year based on :cite:t:`hall_spatial_2010`. The “icclim” method is deprecated but is identical to method “huglin”.

  • cap_value (float) – The value to use for the latitude coefficient when latitude is above 50°N or below 50°S. Only applicable for methods “huglin”, “icclim”, and “interpolated” (default: 1.0).

  • start_date (str | str) – The hemisphere-based start date to consider (north = April, south = October).

  • end_date (str | str) – The hemisphere-based start date to consider (north = October, south = April). This date is non-inclusive.

  • freq (Literal[``’YS’, ``'YS-JAN', 'YS-JUL']) – Resampling frequency (default: “YS”; For Southern Hemisphere, should be “YS-JUL”).

  • ds (xarray.Dataset | Any) – Input dataset.

  • **kwargs (Any) – Additional keyword arguments.

Returns:

The computed index.

Return type:

Any