[gradsusr] Question about why the wind vectors barbs not showing up for the 0-6 KM Shear difference

[Nimrod Micael]

Perfect. Just to verify I am doing the right procedure:

zinterp(u,height,6)
 'u6km=interp'
 zinterp(v,height,6)
 'v6km=interp'
 'shear0006=1.94*mag(u6km-u10,v6km-v10)'
 'set gxout shaded'
 'set cmin 20'
 'set clevs 20 30 40 50 60'
 'set ccols 0 3 7 8 2 6'
 'd shear0006'

 'ushear= u6km-u10'
 'vshear= v6km-v10'


 'set gxout barb'
 'set cmin 20'
 'set arrlab off'
 'set clopts -1 -1 0.14'
 'set arrscl 5'
 'd skip(ushear*1.94,40,40);skip(vshear*1.94,40,40)'


Thanks Jeff you are awesome! :)


On Mon, Sep 2, 2013 at 12:09 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:

> You're still only displaying a scalar quantity.  You need to display the
> shear components separated by a ; to get the barbs to appear.
>
>
> On Mon, Sep 2, 2013 at 10:39 AM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
>
>> oh u10 and v10 is
>>       u10  1  0  U at 10 M (m s-1)
>>       v10  1  0  V at 10 M (m s-1)
>> respectively.
>>
>>
>> On Mon, Sep 2, 2013 at 11:29 AM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
>>
>>> Actually I think I fixed the problem but still didnt get the wind barb...
>>>
>>>  zinterp(u,height,6)
>>>  'u6km=interp'
>>>  zinterp(v,height,6)
>>>  'v6km=interp'
>>>  'shear0006=1.94*mag(u6km-u10,v6km-v10)'
>>>  'set gxout shaded'
>>>  'set cmin 20'
>>>  'd shear0006'
>>>
>>>
>>>  'set gxout barb'
>>>  'set cmin 20'
>>>  'd shear0006'
>>>
>>>
>>> What's going on?
>>>
>>>
>>> On Mon, Sep 2, 2013 at 1:40 AM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
>>>
>>>> Oh my model height is in KM though. Hence why 6 KM and not 600 meters.
>>>>
>>>>
>>>> On Mon, Sep 2, 2013 at 1:39 AM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
>>>>
>>>>> The interpolation is not working for me.
>>>>>
>>>>> I did this:
>>>>>
>>>>> 'umid=zinterp(u,height,6)'
>>>>>  'vmid=zinterp(v,height,6)'
>>>>>  'ulow="zinterp(u,height,0)'
>>>>>  'vlow="zinterp(v,height,0)'
>>>>>  'verticalshear =(umid-ulow)+(vmid-vlow)'
>>>>>  'bulkshear=sqrt(verticalshear)'
>>>>>
>>>>>
>>>>> Still not getting anything after many tries.
>>>>>
>>>>>
>>>>> Thanks!
>>>>>
>>>>>
>>>>> On Sun, Sep 1, 2013 at 11:35 PM, Nimrod Micael <
>>>>> nmicael at aggies.ncat.edu> wrote:
>>>>>
>>>>>> Ohhhhh @Jeff...I see what you are saying...there's an angle to the
>>>>>> direction of the winds...you cant assume that both levels are in the same
>>>>>> direction. That makes perfect sense. Very excellent explanation by the way.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Sun, Sep 1, 2013 at 10:52 PM, Jeff Duda <jeffduda319 at gmail.com>wrote:
>>>>>>
>>>>>>> I suggest you have a look through this page (
>>>>>>> http://mathworld.wolfram.com/VectorAddition.html) and the related
>>>>>>> page linked under "see also" called "vector difference".  You can
>>>>>>> add/subtract two vectors by adding/subtracting the corresponding *
>>>>>>> components* (i.e., the u and v components), and making a vector of
>>>>>>> the resulting sum/difference.  What you seem to be stuck on is taking the
>>>>>>> difference of the *magnitude* of the vectors rather than the
>>>>>>> difference of the components.
>>>>>>>
>>>>>>> I'll use this example to help illustrate this.  Suppose you had a
>>>>>>> westerly wind at 500 mb of 50 kts, and an easterly wind of 50 kts at the
>>>>>>> surface (unlikely except for possibly within a severe thunderstorm, but
>>>>>>> just bear with me).  There is no difference in the wind speed between 500
>>>>>>> mb and the sfc, but there is a difference in the direction.  Clearly there
>>>>>>> is shear, but only if you look at the component form of the wind.  The u-
>>>>>>> and v-components of the 500 mb wind in this example are u = 50, v = 0
>>>>>>> (kts), whereas at the surface, the components are u = -50, v = 0 (kts).
>>>>>>>  Therefore, the shear is given by (u500-usfc)*i* + (v500-vsfc)*j* =
>>>>>>> (50 - -50)*i* + (0-0)*j* = 100*i* + 0*j*.  The shear vector is
>>>>>>> straight out of the west here.  The magnitude is given by sqrt(ushear^2 +
>>>>>>> vshear^2), which is sqrt(100^2 + 0^2) = 100 kts of shear.
>>>>>>>
>>>>>>> Jeff
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> gradsusr mailing list
>>>>>>> gradsusr at gradsusr.org
>>>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Nimrod Micael
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Nimrod Micael
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> Nimrod Micael
>>>>
>>>
>>>
>>>
>>> --
>>> Nimrod Micael
>>>
>>
>>
>>
>> --
>> Nimrod Micael
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
>
> --
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>


-- 
Nimrod Micael
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20130902/e5f9fb6a/attachment-0003.html