How do you determine mixed layer depth?

The depth of the mixed layer is often determined by hydrography—making measurements of water properties. Two criteria often used to determine the mixed layer depth are temperature and sigma-t (density) change from a reference value (usually the surface measurement).

How deep is the mixed layer?

This homogenises a surface layer, called the oceanic mixed layer. Its depth is generally of 50 to 100 metres in winter but it can reach several hundred metres in some regions. When temperature rises in spring and summer, the density at the surface decreases. This tends to stabilise the water column.

What is the approximate thickness of the mixed layer?

This is because the thickness of the surface mixed layer is typically 100 m or less. The pycnocline acts as a porous boundary that allows some kinetic energy to penetrate into deep water.

What is layer depth?

The depth from the surface of the sea to the point above the first major negative thermocline at which sound velocity is maximum.

How is the surface mixed layer depth calculated?

The surface MLDs are estimated here directly on individual profiles with data at observed levels. MLD is defined through the threshold method with a finite difference criterion from a near-surface reference value. A linear interpolation between levels is then used to estimate the exact depth at wich the difference criterion is reached.

Which is the temperature mixed layer depth MLD?

This mixed layer depth is a Temperature-Mixed Layer Depth, or Isothermal Layer Depth. It is reminded that T°C inversions are NOT contained into this isothermal layer! We estimate this MLD, named MLD_DT02, from a fixed threshold on temperature profiles. The criterion is the following :

How are mixed layer depths calculated in Argo?

Mixed layer depths and properties (density, temperature, and salinity) for every profile in the Argo data set. Climatology of monthly mixed layer depths (mean, median, maximum, and standard deviation) and properties (mean potential density, conservative temperature, and absolute salinity) averaged into 1 degree bins.

Which is the most reliable measure of mixing layer depth?

We conclude that overturning length scales give the most reliable measure of mixing layer depth, although conventional shipborne CTDs are seldom capable of sufficiently resolving the overturns. Pergamon 0967-0637 (95)000611^2 Deep-Sea Research I, Vol. 42 No. 9. pp. 1521-1543. 1995 Copyright 1995 Elsevier Science Ltd Printed in Great Britain.