# Turner angle

From AMS Glossary

## Turner angle

A parameter used to define the local stability of an inviscid water column to double- diffusive convection.

Defined as where tan

^{-1}is the four-quadrant arctangent, α is the coefficient of thermal expansion, β is the coefficient of saline contraction,*T*is temperature, and*S*is salinity. If -45° < Tu < 45°, the column is statically stable. If -90° > Tu or Tu > 90°, the column is statically unstable to Rayleigh– Taylor instability. If -90° < Tu < -45°, the column is unstable to diffusive convection. If 45° < Tu < 90°, the column is unstable to salt fingering.