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[IDV #KKG-899085]: Layer windshear in IDV

> Hi
> 
> I have some questions regarding the function "Layer wind shear" in the
> Formula section. I just can't seem to make it work. Maybe I am using
> the formula wrong?
> 
> What I do is the following:
> 
> 1. I choose the formula: Data - Formulas - Grids - Layer windshear
> 
> 2. I want to see the value plotted as a "contour plan view" so I shoose
> the following option:
> 
> 3. Since I want to plot the Deep layer shear (from 1000mb to around 500mb)
> I then choose the desired input accordingly (bottom = 1000, top = 500)
> Is this the correct way to do so?
> 
> 4. I then choose the desired fields. I choose the u-component of the wind
> (isobaric level), the v-component of the wind (isobaric level)... But I
> do not know how I can set the z- value.
> 
> I tried different things for the z-value: geopotential height of isobaric
> level, thickness 1000-500, the formula "layer difference",... I cant seem
> to find a way to get the correct z-value. Every choice I make a choice,
> IDV gives either Python errors or the error: "Can not slice a 2D field".
> 
> Is it possible to send me in the right direction with this
> function? Because I am out of ideas.
> 
> If this works I can then go on to other things like: Significant Tornado
> Paramater, Storm relative Helicity (3km, instead of the fixed value of
> 1,5 km and the Energy helicity index). I would really like to plot these
> values for the assessment of severe weather potential, but I can't seem
> to make the windshear work. And since the STP, SREH & EHI are all based
> on the windshearcalclulation I am therefore stuck.
> 
> Do you see an error in the things I choose? Am I missing something?
> 
> 
> Any help would be much appreciated.
> 
> 
> Best regards,
> 
> 
> Dzengiz Tafa
> 
> 

Hi Dzengiz,
     Sorry for the late response, just back from trip.
     When the first window popup for the layers, you need to change 500 to 
50000, and 850 to 85000 since the unit is "Pa" for this dataset. You don't need 
to know the z value, simply select 3D > Mass > Geopotential height@ isobaric 
surface for the Field:Z.

Let me know if you need more help.


Yuan
 
> 


Ticket Details
===================
Ticket ID: KKG-899085
Department: Support IDV
Priority: High
Status: Closed