Dr. Jackett et Tj. Mcdougall, MINIMAL ADJUSTMENT OF HYDROGRAPHIC PROFILES TO ACHIEVE STATIC STABILITY, Journal of atmospheric and oceanic technology, 12(2), 1995, pp. 381-389
Hydrographic data, be it raw or highly averaged observational data, co
ntain substantial regions having vertical density inversions. An algor
ithm is described that minimally modifies such data so that the result
ing hydrographic casts have vertical buoyancy frequency profiles large
r than a specified lower bound. The method underlying the algorithm is
based on the solution of a constrained weighted least-squares problem
and maximizes the smoothness of the resulting salinity-potential temp
erature diagram. Examples are provided that demonstrate the effectiven
ess of the technique in minimally altering hydrographic data only in t
he immediate vicinity of the data that do not already satisfy the buoy
ancy frequency constraint. A modified equation of state, identical in
form to the international equation of state of seawater but written in
terms of potential rather than in situ temperature, is also provided,
enabling rapid computation of the thermal expansion and saline contra
ction coefficients.