[gradsusr] Question about srh1km(uVAR,vVAR) function
Nimrod Micael
nmicael at aggies.ncat.edu
Sat Sep 7 22:01:47 EDT 2013
I dont know why I am getting this error.
Unknown command: u0.5=zinterp(u,height,0.5)
Unknown command: v0.5=zinterp(v,height,0.6)
Done. Newly defined variable interp has 1 v-field.
Done. Newly defined variable interp has 1.5 u-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 1.5 v-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 2 u-field.
Done. Newly defined variable interp has 2 v-field.
Done. Newly defined variable interp has 2.5 u-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 2.5 v-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 3 u-field.
Done. Newly defined variable interp has 3 v-field.
Done. Newly defined variable interp has 3.5 u-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 3.5 v-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 4 u-field.
Done. Newly defined variable interp has 4 v-field.
Done. Newly defined variable interp has 4.5 u-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 4.5 v-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 5 u-field.
Done. Newly defined variable interp has 5 v-field.
Done. Newly defined variable interp has 5.5 u-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 5.5 v-field.
DEFINE error: Name too long; missing '='
Done. Newly defined variable interp has 6 u-field.
Done. Newly defined variable interp has 6 v-field.
Data Request Error: File number out of range
Variable = u0.5
Error ocurred at column 6
DEFINE error: Invalid expression.
Here's my code:
"u0.5=zinterp(u,height,0.5)"
"v0.5=zinterp(v,height,0.6)"
"u1=zinterp(u,height,1)"
"define v1="zinterp(v,height,1)
"define u1.5="zinterp(u,height,1.5)
"define v1.5="zinterp(v,height,1.5)
"define u2="zinterp(u,height,2)
"define v2="zinterp(v,height,2)
"define u2.5="zinterp(u,height,2.5)
"define v2.5="zinterp(v,height,2.5)
"define u3="zinterp(u,height,3)
"define v3="zinterp(v,height,3)
"define u3.5="zinterp(u,height,3.5)
"define v3.5="zinterp(v,height,3.5)
"define u4 ="zinterp(u,height,4)
"define v4="zinterp(v,height,4)
"define u4.5="zinterp(u,height,4.5)
"define v4.5="zinterp(v,height,4.5)
"define u5="zinterp(u,height,5)
"define v5="zinterp(v,height,5)
"define u5.5="zinterp(u,height,5.5)
"define v5.5="zinterp(v,height,5.5)
"define u6="zinterp(u,height,6)
"define v6="zinterp(v,height,6)
'define umean=(u10+u0.5+u1+u1.5+u2+u2.5+u3.0+u3.5+u4+u4.5+u5+u5.5+u6)/13.0'
'define vmean=(v10+v0.5+v1+v1.5+v2+v2.5+v3.0+v3.5+v4+v4.5+v5+v5.5+v6)/13.0'
'define ushear=u5-u10'
'define vshear=v5-v10'
'define shear=sqrt(ushear*ushear+vshear*vshear)'
'define umotion=((umean+(7.5/(shear))*vshear))'
'define vmotion=((vmean-(7.5/(shear))*ushear))'
'define srh1=((u0.5-umotion)*(v10-vmotion)-(u10-umotion)*(v0.5-vmotion))'
'define srh2=((u1-umotion)*(v0.5-vmotion)-(u0.5-umotion)*(v1-vmotion))'
'define srh1km=srh1+srh2'
'set gxout shaded'
'set clevs 100 150 200 250 300 400 500 600 700 800'
'set ccols 0 14 4 11 5 3 7 12 8 2 6'
'd srh1km'
I dont get what's wrong?
Thanks.
On Sat, Sep 7, 2013 at 4:50 PM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
> Just change it to height coordinates from that script?
>
>
> On Sat, Sep 7, 2013 at 4:49 PM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
>
>> I see... so how would the shear from Surface to 1 km AGL be calculated? I
>> cant find it online.
>>
>> Thanks!
>>
>>
>> On Sat, Sep 7, 2013 at 3:45 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> Because in areas of elevated terrain, the top of the layer in which the
>>> shear is being computed is much closer to the surface than 1 km. Said
>>> another way, they use the 900 mb level as a surrogate for the 1 km level.
>>> If the actual surface pressure is close to 900 mb, however, the vertical
>>> distance between the surface and the surrogate 1 km level is going to be
>>> quite small. Thus, the computed shear value will be expected to be lower
>>> than if you used the 1 km AGL instead.
>>>
>>> Jeff
>>>
>>>
>>> On Sat, Sep 7, 2013 at 1:47 PM, Nimrod Micael <nmicael at aggies.ncat.edu>wrote:
>>>
>>>> @Jeff:
>>>>
>>>> Ok because I find it weird that my 0-1 KM shear values at 16Z in GSO is
>>>> about 1/2 of the value of the observation from a sounding taken at the time
>>>> when using that shr1km(u,v) function. However, when I used Rob Hart's
>>>> plotskew script to plot the sounding...the ERSH matched closer to the
>>>> observation at that time. So I am wondering why such a huge error in that.
>>>>
>>>>
>>>> On Sat, Sep 7, 2013 at 2:08 PM, Jeff Duda <jeffduda319 at gmail.com>wrote:
>>>>
>>>>> If you're calculating 0-1 km SRH over flat terrain near sea level,
>>>>> their computation is within reason. However, if you're on higher terrain
>>>>> or sloped terrain (e.g., the Plains region of the US), you'll want to use a
>>>>> different method.
>>>>>
>>>>> Jeff
>>>>>
>>>>>
>>>>> On Sat, Sep 7, 2013 at 11:28 AM, Nimrod Micael <
>>>>> nmicael at aggies.ncat.edu> wrote:
>>>>>
>>>>>> He stated it's 1 KM MSL.
>>>>>>
>>>>>>
>>>>>>
>>>>>> "However, the question of AGL or MSL depends on your model data
>>>>>> output -
>>>>>> if it compensates the pressure height. GFS IIRC does not do that, so
>>>>>> it
>>>>>> would be MSL.
>>>>>>
>>>>>> To understand the calculation, you can check the original math from
>>>>>> our
>>>>>> website:
>>>>>> http://www.saakeskus.fi/grads-scripts/63-storm-relative-helicity-0-3km
>>>>>> "
>>>>>>
>>>>>> So in order to calculate 0-1 KM shear it has to be 0-1 KM AGL?
>>>>>>
>>>>>>
>>>>>> Thanks.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Fri, Sep 6, 2013 at 1:30 PM, Jeff Duda <jeffduda319 at gmail.com>wrote:
>>>>>>
>>>>>>> I don't use openGrads, so there may be some specifics I'm not aware
>>>>>>> of. uVAR and vVAR are just dummy names for the u- and v-components of the
>>>>>>> wind. The inaccuracies are probably due to the exact specifics with how
>>>>>>> the 0-1 km shear is computed in the script. One big question is how is the
>>>>>>> 1 km layer wind field being computed? Is it just 1 km MSL or 1 km AGL?
>>>>>>> Those are things you need to find out. I recommend asking the authors
>>>>>>> whose email addresses are given on the linked page.
>>>>>>>
>>>>>>> Jeff
>>>>>>>
>>>>>>>
>>>>>>> On Fri, Sep 6, 2013 at 12:20 PM, Nimrod Micael <
>>>>>>> nmicael at aggies.ncat.edu> wrote:
>>>>>>>
>>>>>>>> *srh1km*(*uVAR,vVAR*)
>>>>>>>> What is uVAR and vVAR? I dont have those variables.
>>>>>>>>
>>>>>>>> http://opengrads.org/doc/udxt/saakeskus/
>>>>>>>>
>>>>>>>> I tried replacing uVar and vVar with u and v wind but I am getting
>>>>>>>> some inaccuracies with the 0-1 KM shear. Can someone help me out?
>>>>>>>>
>>>>>>>> Thanks.
>>>>>>>>
>>>>>>>> --
>>>>>>>> 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
>>>>
>>>> _______________________________________________
>>>> 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
>
--
Nimrod Micael
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