[gradsusr] Ensemble mean & Anomaly

[Jeff Duda]

Anomalies can be defined in many ways. Probably the common one is a
climatological anomaly. In that case you'll need to obtain data containing
climatological mean fields. The anomaly in that case is just [field -
climatological mean]. I do not know off the top of my head where such
fields can be found, but there are websites that provide anomaly graphics,
so someone out there knows where you can find those data.

Jeff

On Wed, Jan 20, 2016 at 9:50 AM, Chorley Weather <
weatherstu at chorleyweather.com> wrote:

> Hi jeff,
>
> I was using this grads server link
> http://nomads.ncep.noaa.gov:9090/dods/gens/gens20160120/gep_all_00z but
> ill download the grib files and try it that way. As for the 'Anomaly'
> question I was actually on about GFS data. I would like to produce a 500mb
> height anomaly like the image attached but dint know how to define this.
>
>
>
> regards,
>
> Stuart.
>
>
>
> On 20-01-2016 15:10, Jeff Duda wrote:
>
> From my experience with GEFS data, each ensemble member is contained in a
> separate file. So I hope your control file uses templating and has an EDEF
> entry. If it doesn't, or you don't have all the data files, then that
> explains why your 'define ensmean=ave(t850,e=1,e=21)' command is just
> giving you the control member (because it's the only one present).
>
> I assume by "anomaly" you mean the difference between a given ensemble
> member and the ensemble mean. In that case, just plot the difference field
> between an ensemble member and the ensemble mean. For instance,
>
> 'set e 2'
> 'd tmpprs - ensmean'
>
> Jeff Duda
>
> On Wed, Jan 20, 2016 at 8:05 AM, Chorley Weather <
> weatherstu at chorleyweather.com> wrote:
>
>> Hi all,
>>
>>
>>
>> I have a couple of questions, firstly I am trying get the mean run in a
>> spaghetti graph of the GEFS but I seem to keep getting the control run.
>> Here is the script:
>>
>> 'set t 1 65'
>> 'set e 1'
>> 'set csmooth on'
>> 'set cmark 0'
>> 'set lat 53';'set lon -2.23'
>> 'set vrange -30 30'
>> 'define t850=tmpprs(lev=850)-273.16'
>> 'define ensmean=ave(t850,e=1,e=21)'
>> 'set gxout line'
>> 'set ccolor 2'
>> 'set cthick 8'
>> 'd ensmean'
>>
>>
>>
>> Second question, using the GFS how do I produce anomaly charts with this
>> script, im not sure how to define it.....
>>
>> 'set t 'i
>> 'set grads off'
>> 'set csmooth on'
>> 'define geopotdam = hgtprs(lev=500)/10'
>> 'color -gxout shaded -30 30 1 -kind blue->white->red-> -xcbar 10.1 10.3
>> 0.7 7.74 -fs 10'
>>
>>
>>
>> Regards,
>> --
>>
>> Stuart Markham
>>
>>
>> _______________________________________________
>> 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 listgradsusr at gradsusr.orghttp://gradsusr.org/mailman/listinfo/gradsusr
>
>
> --
>
> Stuart Markham
>
>


-- 
Jeff Duda
Graduate research assistant
University of Oklahoma School of Meteorology
Center for Analysis and Prediction of Storms
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