ctdfjorder.CTD.CTD.add_mld_bf(self, min_qi=0.0) → None

Calculates the mixed layer depth (MLD) using the max buoyancy frequency (N^2) method based on salinity profiles.

Parameters:

min_qi – Minimum quality index score to be considered a valid MLD.

Notes

The mixed layer depth (MLD) is determined by identifying the depth where the maximum buoyancy frequency occurs. After finding this depth, the Quality Index (QI) is calculated to assess the reliability of the MLD. The Quality Index is given by:

\[QI = 1 - \frac{\sigma_{A1}}{\sigma_{A2}}\]

where:

• \(\sigma_{A1}\) is the standard deviation of the potential density within the mixed layer depth

• \(\sigma_{A2}\) is the standard deviation of the potential density within 1.5 times the mixed layer depth.

The calculated QI must be greater than or equal to min_qi for the MLD to be considered valid. If invalid or incalculable MLD is reported as None.

Raises:

NoSamplesError – When the function is called on a CTD object with no data.

See also

add_mld

Method to calculate and add MLD to a dataset using different methods, including density threshold.