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20011130: 20011130: Computing the standard deviation

Andy,

Ok. Still can't see any problem (other than TIMSTN which exceeds the default
number of times allow in a GEMPAK file). I used TIMSTN=24/100 for
24 times, 100 additional stations.

Rereading your message below, you say you use gdgsfc to write the gddiag values
to a surface file. Then output to a .txt file.

Have you looked at the values in the surface file with sflist?
what are you using to output the data to your .txt file?

I guess I should see your gdgsfc commands, the SAC output from sflist
as well.

Steve Chiswell
Unidata User SUpport



>From: "Siffert, Andy" <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200111301947.fAUJlCN29728

>
>Steve,
>
>This is the surface file I created. 
>
>
>TMC1 = TMPKC001
>AVRG=  Average of all members
>STAN= Will equal Standard deviation  once I can figure out b^2
>MINS= Average - one Standard Deviation
>PLUS= Average + one Standard Deviation 
>
>
>
>
>sfcfil<<EOF
>SFOUTF=/home/met-user/andy/2meter_temp.sfc
>SFPRMF=TMC1;AVRG;STAN;MINS;PLUS
>STNFIL=/usr/local/nawips/gempak/tables/stns/2m_temp.tbl
>SHIPFL=NO
>TIMSTN=1000 
>SFFSRC=text
>
>run
>   
>EOF
>
>Not sure if I understand this part 2)
>2) specify a parameter list and optionally the data range and resolution
>   of the data.
>
>
>Thanks,
>Andy 
>
>-----Original Message-----
>From: Unidata Support [mailto:address@hidden]
>Sent: Friday, November 30, 2001 1:32 PM
>To: Siffert, Andy
>Cc: 'Unidata Support'
>Subject: 20011130: 20011130: Computing the standard deviation 
>
>
>
>Andy,
>
>this confirms that it is not a problem related to your
>calculation of C in gddiag. previously, you had said you saw values
>of -9999 for C, but we now can assume that it is when you interpolate the
>grid to the surface file using gdgsfc.
>
>When you use gdgsfc, the surface file must already exist. Presumably
>you have created the surface file using sfcfil. The resolution of the
>data to be stored in the surface file is specified with the SFPRMF
>parameter.
>
>So, we need to see what you have done for SFPRMF in sfcfil.
>Typically, you can either:
>1) specify a packing file
>2) specify a parameter list and optionally the data range and resolution
>   of the data.
>
>Can you provide information on what you have used for SFPRMF?
>
>Steve Chiswell
>Unidata User Support
>
>
>
>
>
>>From: "Siffert, Andy" <address@hidden>
>>Organization: UCAR/Unidata
>>Keywords: 200111301919.fAUJJEN28104
>
>>
>>Steve,
>>I'm some what new to Gempak,
>>I'm not sure what I'm suppose to be looking for when I use gdinfo or gdcntr
>>
>>When using gdinfo and gdcntr
>>I specify "b" or "c" 
>>and it shows that they are there.
>>Is that what you wanted me to see??
>>
>>I do agree with you that is it s truncating problem. 
>>When you get a chance it would be great if you could return this e-mail and
>>I could give you a call to get a better understanding of where the problem
>>might be.
>>Thanks,
>>Andy 
>>
>>
>>
>>-----Original Message-----
>>From: Unidata Support [mailto:address@hidden]
>>Sent: Friday, November 30, 2001 10:09 AM
>>To: Siffert, Andy
>>Cc: 'Unidata Support'
>>Subject: 20011130: 20011129: Computing the standard deviation 
>>
>>
>>
>>
>>Andy,
>>
>>start by forgetting about gdgsfc to start.
>>
>>After you create "b" which you know works, you should be able to use
>>gdlist or gdcntr etc to view it.
>>
>>Now, if you create "c", you should still be able to view it. Verify that
>>first- before doing anything with gdgsfc,
>>
>>What I see in your previous message is that your terms are small. And when
>>you 
>>square them, they of course get smaller. The SFLIST output will be
>>truncated to 2 decimal places which does create a display problem, unless
>>you
>>scale the values with SFPARM=sstdv*100 for example.
>>
>>If you are using gdgsfc to write the output to the surface file, then the
>>packing information for the surface file must correspond to the
>>resolution of the data (see $GEMTBL/pack for examples). 
>>
>>Anyhow, let me know first if you see C in the grid file before the gdgsfc
>>interpolation to a surface file. If that is the case, then we can focus on
>>what
>>you need to use with gdgsfc. As I mentioned yesterday, I didn't see
>>any problem here with gddiag.
>>
>>Steve Chiswell
>>Unidata User Support
>>
>>
>>
>>
>>>From: "Siffert, Andy" <address@hidden>
>>>Organization: UCAR/Unidata
>>>Keywords: 200111301327.fAUDRTN10376
>>
>>>Steve good morning.
>>>We are running a newer version of Red Hat Linux and using GEMPACK 5.6.c.1 
>>>(I think c.1) 
>>>
>>> MRF ensemble grid I'm using. 
>>>GRID NAVIGATION: 
>>>     PROJECTION:          CED                 
>>>     GRID SIZE:          144  73
>>>     LL CORNER:             -90.00      0.00
>>>     UR CORNER:              90.00     -2.50
>>>
>>>First using a series of gddiag commands I create an average using all the
>>>members.  
>>>The average is then stored in the same .gem as the 10 members. 
>>>Next I individually take the members and compute the variance, from the
>>>variance you take the sqrt to obtain the standard deviation. 
>>>
>>>The problem is in the calculation of the variance.
>>>as noted in my previous e-mail.
>>>
>>>As far as viewing the output. Once, all the calculation for all the
>members
>>>and all forecast hours, are computed in gddiag. I then use gdgsfc to write
>>>the selected surface that were written to file in the gddiag commands.
>Then
>>>using gdgsfc I write everything to a .txt file. 
>>>
>>>P.S. I know that GEMPAK knows what b is because if I
>>>for example use the 11/30 00z, TMPKC001 member from SAC 
>>>The:
>>>AVG (of all the members) = 43.76
>>>TMPKC001 = 43.46
>>>AVG - TMPKC001 = .30 (b)
>>>mul(b,b)= .25
>>>exp(b,2)= -9999 (however for some other STN ID's I do not get -9999).
>>>exp(.30,2)= .09
>>>mul(.30,.30)= .09 which is what I want but since .30 is just one example
>of
>>>many members I need to use (b).
>>>
>>>Hope this additional information helps.
>>>Thanks for your help.
>>>Andy
>>>
>>>
>>>
>>>-----Original Message-----
>>>From: Unidata Support [mailto:address@hidden]
>>>Sent: Thursday, November 29, 2001 3:33 PM
>>>To: Siffert, Andy
>>>Cc: address@hidden
>>>Subject: 20011129: Computing the standard deviation 
>>>
>>>
>>>
>>>Andy,
>>>
>>>I cannot duplicate your problem here using GEMPAK 5.6.E.1 on my SGI
>>>with the 00Z ensemble grids on the 1x1 degree output today.
>>>What platform combination are you using?.
>>>
>>>Where is your "example of output" coming from? GDLIST? GDPLOT2?
>>>
>>>Steve Chiswell
>>>
>>>
>>>
>>>>From: "Siffert, Andy" <address@hidden>
>>>>Organization: UCAR/Unidata
>>>>Keywords: 200111291537.fATFbvN06225
>>>
>>>>
>>>>Steve
>>>>I Think?
>>>>
>>>>I'm not sure how large or small my problem is. However, I hope I made my
>>>>problem clear below.
>>>>What I'm trying to do in gempak is take the square of small number and
>>>store
>>>>it in a .gem file using GDDIAG. 
>>>>
>>>>What I'm trying to do is compute the standard deviation in 2 m
>temperature
>>>>from the MRF ensembles 
>>>>
>>>>here is the part of interest.
>>>>
>>>>#converts member to degrees F
>>>>gddiag<<EOF
>>>>GDFILE   = /home/met-user/andy/$file
>>>>GDOUTF   = /home/met-user/andy/$file
>>>>GFUNC    = add(mul(sub(TMPKC001,273),1.8),32)))
>>>>GDATTIM  = $YY$MM$DD/${cycle}00F$zero$fff
>>>>GLEVEL   = 2
>>>>GVCORD   = hght
>>>>GRDNAM  = a
>>>>GPACK    = 
>>>>run
>>>>
>>>>EOF
>>>>
>>>>#Subtract avg from a member of the ensembles
>>>>gddiag<<EOF
>>>>GDFILE   = /home/met-user/andy/$file
>>>>GDOUTF   = /home/met-user/andy/$file
>>>>GFUNC    = sub(avg,a)
>>>>GDATTIM  = $YY$MM$DD/${cycle}00F$zero$fff
>>>>GLEVEL   = 2
>>>>GVCORD   = hght
>>>>GRDNAM   = b
>>>>GPACK    =
>>>>run
>>>>
>>>>EOF
>>>>
>>>>gddiag<<EOF
>>>>GDFILE   = /home/met-user/andy/$file
>>>>GDOUTF   = /home/met-user/andy/$file
>>>>GFUNC    = expi(b,2)
>>>>GDATTIM  = $YY$MM$DD/${cycle}00F$zero$fff
>>>>GLEVEL   = 2
>>>>GVCORD   = hght
>>>>GRDNAM   = c
>>>>GPACK    =
>>>>run
>>>>
>>>>EOF
>>>>
>>>>This is where the problem is: I want to take the square of b (b^2).
>>>>The output is wrong. 
>>>>
>>>>I have even try doing
>>>>    GFUNC = mul (b,b) 
>>>>which should be the same as b^2?
>>>>If I use 
>>>>   GFUNC = EXP(b,2)  
>>>>I get -9999 or the wrong answer also.
>>>>
>>>>Example of output
>>>>  Avg -  a  =  b^2  =    c       The output I recive from C in gempak
>>>>43.31-42.82 = .49 ^2 = .2401      .27
>>>>53.56-53.54 = .02 ^2 = .0004      -9999
>>>>
>>>>Thanks for your help.
>>>>Andy 
>>>>
>>>>
>>>>
>>>>****************************************
>>>>               Andy Siffert                  
>>>>        Aquila Weather Desk           
>>>>     Research and Development     
>>>>  1100 Walnut Street, Suite 3300  
>>>>      Kansas City, MO 64106         
>>>>             816-527-1247                 
>>>>          Fax: 816-527-4247            
>>>>****************************************
>>>>
>>>
>>>**************************************************************************
>*
>>*
>>><
>>>Unidata User Support                                    UCAR Unidata
>>Program
>>><
>>>(303)497-8644                                                  P.O. Box
>>3000
>>><
>>>address@hidden                                   Boulder, CO
>>80307
>>><
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>>>Unidata WWW Service                        http://www.unidata.ucar.edu/
>>><
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>>><
>>>
>>
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>><
>>Unidata User Support                                    UCAR Unidata
>Program
>><
>>(303)497-8644                                                  P.O. Box
>3000
>><
>>address@hidden                                   Boulder, CO
>80307
>><
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>>Unidata WWW Service                        http://www.unidata.ucar.edu/
>><
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>Unidata User Support                                    UCAR Unidata Program
><
>(303)497-8644                                                  P.O. Box 3000
><
>address@hidden                                   Boulder, CO 80307
><
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>Unidata WWW Service                        http://www.unidata.ucar.edu/
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