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

[Nimrod Micael]

Here's for your reference: @Jeff

"The 0-6 km bulk shear (really, it's the bulk wind difference) is just the
vector difference between the surface wind and the 6 km wind. A simple
approximation is the difference between the surface and 500 mb winds, which
works well for low-elevation sounding sites."


On Sun, Sep 1, 2013 at 7:12 PM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:

> @Jeff,
>
> I see but is it approximation? That's my understanding from Rich
> Thompson's post.
> http://www.stormtrack.org/forum/archive/index.php/t-23323.html
>
>
> On Sun, Sep 1, 2013 at 6:55 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>
>> The contours are just the magnitude of the shear vector, but that's
>> not the same as the difference in wind speed at two levels.
>>
>> On Sun, Sep 1, 2013 at 4:58 PM, Nimrod Micael <nmicael at aggies.ncat.edu>
>> wrote:
>> > I see what your saying Jeff. But what if you are interested in the
>> magnitude
>> > only of u and v and not the two separate u and v vectors. I am trying
>> to get
>> > a map like this....
>> >
>> > http://www4.ncsu.edu/~nwsfo/storage/cases/20100425/shr6_10042600.gif
>> >
>> > This doesnt have two separate vectors: u and v.
>> >
>> >
>> >
>> >
>> >
>> > On Sun, Sep 1, 2013 at 5:52 PM, Jeff Duda <jeffduda319 at gmail.com>
>> wrote:
>> >>
>> >> The way you're doing it, you're only computing the difference in wind
>> >> speed between two layers.  If you're trying to calculate vertical wind
>> >> shear, you should be calculating the vector difference, which is the
>> >> difference in the components.  So you should have a delta-U wind
>> >> component of the shear (u500-usfc) and a delta-V component of the
>> >> shear (v500-vsfc).  Those are the two quantities you would display to
>> >> get the vectors.
>> >>
>> >> Jeff
>> >>
>> >> On Sun, Sep 1, 2013 at 3:39 PM, Nimrod Micael <nmicael at aggies.ncat.edu
>> >
>> >> wrote:
>> >> > I see Jeff. So then how would i make it to display the magnitude of
>> u,v
>> >> > for
>> >> > 2 different levels then? Since I am taking the difference between the
>> >> > 500 mb
>> >> > wind and the sfc wind?
>> >> >
>> >> >
>> >> >
>> >> > On Sun, Sep 1, 2013 at 4:33 PM, Jeff Duda <jeffduda319 at gmail.com>
>> wrote:
>> >> >>
>> >> >> displaying wind barbs requires two inputs in the display command
>> >> >> (i.e., 'd u;v').  You are only supplying one.
>> >> >>
>> >> >> Jeff Duda
>> >> >>
>> >> >> On Sun, Sep 1, 2013 at 2:53 PM, Nimrod Micael <
>> nmicael at aggies.ncat.edu>
>> >> >> wrote:
>> >> >> > The shaded is plotting fine but the wind barb is not showing up.
>> Can
>> >> >> > anyone
>> >> >> > help me out why?
>> >> >> >
>> >> >> > 'set gxout shaded'
>> >> >> > 'set lev 1000'
>> >> >> > 's= mag(u,v)'
>> >> >> > 'set lev 500'
>> >> >> > 'a = mag (u,v)'
>> >> >> > 'set cmin 20'
>> >> >> > 'bulk = (a-s)*1.92'
>> >> >> > 'd bulk'
>> >> >> >
>> >> >> > 'set gxout barb'
>> >> >> > 'set lev 1000'
>> >> >> > 'barbs= mag(u,v)'
>> >> >> > 'set lev 500'
>> >> >> > 'barba = mag (u,v)'
>> >> >> > 'set cmin 20'
>> >> >> > 'bulkb = (barba-barbs)*1.92'
>> >> >> > 'd bulkb'
>> >> >> >
>> >> >> >
>> >> >> > Wind vectors are not showing up. Why???
>> >> >> >
>> >> >> > Thanks.
>> >> >> >
>> >> >> > --
>> >> >> > Nimrod Micael
>> >> >> >
>> >> >> > _______________________________________________
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>> >> >> > 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
>> >> >
>> >> > _______________________________________________
>> >> > 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
>> >
>> > _______________________________________________
>> > 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
>



-- 
Nimrod Micael
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