polaris.tasks.ocean.horiz_press_grad.reconstruction.layer_deviation

polaris.tasks.ocean.horiz_press_grad.reconstruction.layer_deviation(slope: DataArray, pressure_mid: DataArray, pressure: DataArray | float) → DataArray[source]

The deviation from the layer mean, slope * (p - p^mid).

This is the Theta' of [vert-recon]. It integrates to zero over the layer because pressure_mid is the exact arithmetic midpoint of the two interface pressures.

Parameters:

slope (xarray.DataArray) – The slope from linear_slope().
pressure_mid (xarray.DataArray) – Mid-layer sea gauge pressure in Pa.
pressure (xarray.DataArray or float) – The pressure at which to evaluate, in Pa.

Returns:

deviation (xarray.DataArray) – The deviation from the layer mean.