<p>I am trying to locate saddle points or commonly known as <a href="https://en.wikipedia.org/wiki/Col_(meteorology)" rel="nofollow noreferrer">"col" in synoptic meteorology</a>. This is "z" in the following figure.<a href="https://i.sstatic.net/Lm2MF.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Lm2MF.png" alt="enter image description here"></a></p>

<p><strong>References</strong>
Here are some of the references regarding this.</p>

<p>a). <a href="http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Def/backgr.htm" rel="nofollow noreferrer">http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Def/backgr.htm</a></p>

<p>b). <a href="https://www.meted.ucar.edu/labs/synoptic/kinematics/vort_defzones/navmenu.php?tab=1&amp;page=3-0-0&amp;type=flash" rel="nofollow noreferrer">https://www.meted.ucar.edu/labs/synoptic/kinematics/vort_defzones/navmenu.php?tab=1&amp;page=3-0-0&amp;type=flash</a></p>

<p><strong>What I want</strong>
1. I would like to know what are the characteristics of these points in terms of divergence, sea level pressure, relative humidity or moisture, etc.
I will be automatically detecting these points from the given characteristics.</p>

<p>I'll appreciate any help.</p>

CC BY-SA 4.0
2019-05-21T06:56:02.567Z
@gansub..as always..thanks for the prompt response. I added a few references.
Lyndz
CC BY-SA 4.0
2019-05-21T11:59:47.270Z
yes. thank you. I will also have to look into that.
Lyndz
CC BY-SA 4.0
2019-05-21T12:46:07.850Z
Mathematically, a saddle point is a minimum amongst one dimension and a maximum along another. The detection thereof should be straight forward. Also characteristics can have different meanings, are you referring to the propagating characteristics of a hyperbolic differential equation, or 'characteristic' as 'property'?
AtmosphericPrisonEscape
CC BY-SA 4.0
2019-05-22T02:31:36.947Z
@AtmosphericPrisonEscape..gunsub is correct, I just wanted to know the properties of saddle points.
Lyndz
CC BY-SA 4.0
2019-05-22T11:07:07.607Z
@Lyndz: Right, I guess I was mainly confused about the formulation of the question. Not a full answer, but: Once you have the flow field, you can at least compute divergence and pressure in analytically, right? Humidity I don't know about.
AtmosphericPrisonEscape
<meteorology><synoptic>
Characteristics of saddle points in stream line charts
Lyndz
# Characteristics of saddle points in stream line charts

(Asked by: username_0 on 2019-05-21)

I am trying to locate saddle points or commonly known as ["col" in synoptic meteorology](https://en.wikipedia.org/wiki/Col_(meteorology)). This is "z" in the following figure.[![enter image description here](https://i.sstatic.net/Lm2MF.png)](https://i.sstatic.net/Lm2MF.png)

**References**
Here are some of the references regarding this.

a). <http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Def/backgr.htm>

b). <https://www.meted.ucar.edu/labs/synoptic/kinematics/vort_defzones/navmenu.php?tab=1&page=3-0-0&type=flash>

**What I want**
1. I would like to know what are the characteristics of these points in terms of divergence, sea level pressure, relative humidity or moisture, etc.
I will be automatically detecting these points from the given characteristics.

I'll appreciate any help.

**Tags:** meteorology, synoptic

> **Comments:**
> **username_0**: @gansub..as always..thanks for the prompt response. I added a few references.  
> **username_0**: yes. thank you. I will also have to look into that.  
> **username_1**: Mathematically, a saddle point is a minimum amongst one dimension and a maximum along another. The detection thereof should be straight forward. Also characteristics can have different meanings, are you referring to the propagating characteristics of a hyperbolic differential equation, or 'characteristic' as 'property'?  
> **username_0**: @username_1..gunsub is correct, I just wanted to know the properties of saddle points.  
> **username_1**: @username_0: Right, I guess I was mainly confused about the formulation of the question. Not a full answer, but: Once you have the flow field, you can at least compute divergence and pressure in analytically, right? Humidity I don't know about.  

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