windpowerlib.temperature.linear_gradient

windpowerlib.temperature.linear_gradient(temperature, temperature_height, hub_height)[source]

Calculates the temperature at hub height using a linear gradient.

A linear temperature gradient of -6.5 K/km is assumed. This function is carried out when the parameter temperature_model of an instance of the ModelChain class is ‘temperature_gradient’.

Parameters:

  • temperature (pandas.Series or numpy.array) – Air temperature in K.

  • temperature_height (float) – Height in m for which the parameter temperature applies.

  • hub_height (float) – Hub height of wind turbine in m.

Returns:

Temperature at hub height in K.

Return type:

pandas.Series or numpy.array

Notes

The following equation is used [1]:

T_{hub}=T_{air}-0.0065\cdot\left(h_{hub}-h_{T,data}\right)

with:

T: temperature [K], h: height [m]

h_{T,data} is the height in which the temperature T_{air} is measured and T_{hub} is the temperature at hub height h_{hub} of the wind turbine.

Assumptions:

  • Temperature gradient of -6.5 K/km (-0.0065 K/m)

References