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# Conversion Indicators
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Specialized indicators for converting between climate-related units and computing derived indices like heat index, wind chill, and humidity measures. These indicators are essential for human comfort assessment and meteorological applications.
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## Capabilities
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### Heat Stress Indices
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Heat stress and thermal comfort indices for human health and safety assessment.
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```python { .api }
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def heat_index(tas, hurs, freq="YS"):
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    """
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    Heat index combining temperature and humidity effects.
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    Parameters:
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    - tas: xr.DataArray, daily mean or maximum temperature
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    - hurs: xr.DataArray, daily relative humidity
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    - freq: str, resampling frequency (default "YS")
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    Returns:
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    xr.DataArray: Heat index values
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    """
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def humidex(tas, hurs, freq="YS"):
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    """
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    Humidex (Canadian humidity index) for perceived temperature.
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    Parameters:
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    - tas: xr.DataArray, daily temperature
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    - hurs: xr.DataArray, daily relative humidity
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    - freq: str, resampling frequency
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    Returns:
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    xr.DataArray: Humidex values
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    """
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def wind_chill_index(tas, sfcwind, freq="YS"):
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    """
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    Wind chill index for perceived cold temperature.
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    Parameters:
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    - tas: xr.DataArray, daily temperature
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    - sfcwind: xr.DataArray, daily wind speed
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    - freq: str, resampling frequency
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    Returns:
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    xr.DataArray: Wind chill index values
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    """
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```
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### Unit Conversion Indicators
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Temperature and precipitation unit conversion utilities.
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```python { .api }
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def temperature_sum(tas, thresh="0 degC", freq="YS"):
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    """
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    Temperature sum above/below threshold with unit conversion.
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    Parameters:
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    - tas: xr.DataArray, daily temperature with units
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    - thresh: str, threshold temperature with units
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    - freq: str, resampling frequency
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    Returns:
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    xr.DataArray: Temperature sum in degree-days
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    """
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def rain_approximation(prsn, tas, thresh="0 degC", freq="YS"):
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    """
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    Approximate rainfall from snowfall using temperature threshold.
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    Parameters:
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    - prsn: xr.DataArray, daily snowfall data
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    - tas: xr.DataArray, daily temperature
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    - thresh: str, temperature threshold for rain/snow (default "0 degC")
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    - freq: str, resampling frequency
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    Returns:
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    xr.DataArray: Approximated rainfall
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    """
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def snowfall_approximation(pr, tas, thresh="0 degC", freq="YS"):
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    """
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    Approximate snowfall from precipitation using temperature threshold.
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    Parameters:
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    - pr: xr.DataArray, daily precipitation data
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    - tas: xr.DataArray, daily temperature
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    - thresh: str, temperature threshold for rain/snow (default "0 degC")
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    - freq: str, resampling frequency
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    Returns:
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    xr.DataArray: Approximated snowfall
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    """
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```
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## Usage Examples
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```python
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import xarray as xr
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import xclim.convert as xcc
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# Load weather data
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ds = xr.open_dataset("weather.nc")
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tas = ds.tas
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hurs = ds.hurs 
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sfcwind = ds.sfcwind
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# Calculate heat stress indices
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heat_idx = xcc.heat_index(tas, hurs, freq="YS")
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humidex_vals = xcc.humidex(tas, hurs, freq="YS")
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wind_chill = xcc.wind_chill_index(tas, sfcwind, freq="YS")
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```