polaris.tasks.ocean.horiz_press_grad.eos_expansion.specvol_coefficients

polaris.tasks.ocean.horiz_press_grad.eos_expansion.specvol_coefficients(temperature: DataArray, salinity: DataArray, pressure: DataArray) → Dataset

The four coefficients of [alpha-derivs], evaluated at each cell’s own layer-mean state.

Parameters:

• temperature (xarray.DataArray) – Conservative temperature in degC. Invalid layers may be NaN and stay NaN.

• salinity (xarray.DataArray) – Absolute salinity in g kg-1, on the same points.

• pressure (xarray.DataArray) – Sea gauge pressure in Pa, on the same points. This module follows the rest of Polaris in using Pa, and converts to dbar at the gsw call.

Returns:

coefficients (xarray.Dataset) – alpha_0 (m3 kg-1), alpha_theta (m3 kg-1 degC-1), alpha_s (m3 kg-1 / (g kg-1)) and alpha_p (m3 kg-1 Pa-1), on the dims of the inputs.