Difference between revisions of "Turner angle"

From Glossary of Meteorology
 
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== Turner angle ==
 
== Turner angle ==
  
<div class="definition"><div class="short_definition">A [[parameter]] used to define the local [[stability]] of an inviscid [[water]] column to double-diffusive [[convection]].</div><br/><div class="paragraph">It is defined as  <div class="display-formula"><blockquote>[[File:ams2001glos-Te48.gif|link=|center|ams2001glos-Te48]]</blockquote></div> where tan<sup>&#8722;1</sup> is the four-quadrant arctangent, ''&#x003b1;'' is the [[coefficient of thermal expansion]], ''&#x003b2;'' is the equivalent coefficient for the addition of [[salinity]] (sometimes referred to as saline contraction because the addition of salinity reduces the volume), ''T'' is [[temperature]], and ''S'' is [[salinity]]. If &#8722;45&#x000b0; &lt; Tu &lt; 45&#x000b0;, the  column is [[static stability|statically stable]]. If &#8722;90&#x000b0; &gt; Tu or Tu &gt; 90&#x000b0;, the column is statically unstable to Rayleigh&ndash;Taylor [[instability]]. If &#8722;90&#x000b0; &lt; Tu &lt; &#8722;45&#x000b0;, the column is unstable to [[diffusive convection]]. If 45&#x000b0;  &lt; Tu &lt; 90&#x000b0;, the column is unstable to [[salt fingering]].</div><br/> </div>
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<div class="definition"><div class="short_definition">A [[parameter]] used to define the local [[stability]] of an inviscid [[water]] column to double-diffusive [[convection]].</div><br/><div class="paragraph">It is defined as  <div class="display-formula"><blockquote>[[File:ams2001glos-Te48.gif|link=|center|ams2001glos-Te48]]</blockquote></div> where tan<sup>&#8722;1</sup> is the four-quadrant arctangent; ''&#x003b1;'' is the [[coefficient of thermal expansion]]; ''&#x003b2;'' is the equivalent coefficient for the addition of [[salinity]], sometimes referred to as the "coefficient of saline contraction;" ''T'' is [[temperature]]; and ''S'' is [[salinity]]. If &#8722;45&#x000b0; &lt; Tu &lt; 45&#x000b0;, the  column is [[static stability|statically stable]]. If &#8722;90&#x000b0; &gt; Tu or Tu &gt; 90&#x000b0;, the column is statically unstable to Rayleigh&ndash;Taylor [[instability]]. If &#8722;90&#x000b0; &lt; Tu &lt; &#8722;45&#x000b0;, the column is unstable to [[diffusive convection]]. If 45&#x000b0;  &lt; Tu &lt; 90&#x000b0;, the column is unstable to [[salt fingering]].</div><br/> </div>
  
''Term edited 1 March 2021''
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''Term edited 8 March 2021''
  
 
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Latest revision as of 06:25, 8 March 2021



Turner angle

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

It is defined as
ams2001glos-Te48
where tan−1 is the four-quadrant arctangent; α is the coefficient of thermal expansion; β is the equivalent coefficient for the addition of salinity, sometimes referred to as 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.

Term edited 8 March 2021