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[IDV #ALV-304205]: 0-6km Shear in IDV

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  • Subject: [IDV #ALV-304205]: 0-6km Shear in IDV
  • Date: Tue, 15 May 2018 14:34:15 -0600
> Hi,
> 
> I've been working with wind shear using NARR files in IDV. The wind shear
> formulas given only allow the differences between isobaric surfaces (ex.
> 1000mb-500mb). However, wouldn't this become problematic in areas of higher
> elevations, like towards the Rockies?
> 
> So now I'm trying to plot 0-6km shear. I was able to create a formula to
> plot 2m to a specific pressure level. Here is the formula I have used so
> far for 2m-500mb Wind Shear:
> 
> sqrt((make2D(v500)-make2D(v10))**2+(make2D(u500)-make2D(u10))**2)
> 
> 
> I had some 2D/3D issues initially, so I added make2D to the equation.
> 
> 
> I'm wondering if there was a way to get the program to plot the shear from
> 2m to 6km rather than 2m to Pressure Level. The only options for the U/V
> Specified Height Above Ground options are 10m and 30m.
> 
> 
> I've also noticed this ordeal on the soundings. They all plot at 1000mb.
> 
> 
> Thanks,
> Cody
> 
> 
Hi Cody,

The wind shear is defined as:

shear = sqrt((u(top)-u(bottom))^2 + (v(top)-v(bottom))^2)/zdiff

The problem is to figure out the zidff in your situation. The 2 meter surface 
wind can be at
the 1502 meter altitude in the Rockies, it would be trick here to get the zdiff 
value. You may need to write your own
formula. I am open to any solution.


Yuan

Ticket Details
===================
Ticket ID: ALV-304205
Department: Support IDV
Priority: Normal
Status: Open
===================
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