[gradsusr] function

Michael Fiorino michael.fiorino at noaa.gov
Thu Jul 19 04:16:03 EDT 2012


hi Wendi, when I have problems like this, I break up the expressions and then take a look at 
each part, e.g.

set t 1 2
q dim # check the dim environment
# do a 'd' after each define to see if it makes sense...
# ref is a 3-D variable?  x,y,t?
r1=const(ref,10.0,-a)
r2=ref*0.10
p1=pow(r1,r2)
p12=p1/200.0
p22=const(ref,5.0/8.0,-a)
R=pow(p12,p22)
set t 1
precip=sum(R,t=1,t=2)
d precip

ciao ciao Mike


On 7/12/12 17:45 , Charles Seman wrote:
> Wendi,
> era
>   From a GrADS perspective, the commands you list below look OK to me.
>
> Chuck
>
> On 07/12/2012 05:03 AM, wendi harjupa wrote:
>> Dear Mr Chuck
>>
>> Thank you very much for your explanation,
>> I am sorry,  I want to ask you more...
>>
>> If I have time series data is 4485, so can I make the script like this:
>>
>> 'set t 1 4485'
>> 'R=pow((pow(10, ref/10))/200,5/8)'
>> 'set t 1' ;* see discussion below
>> 'd sum(R/15, t=1, t=4485)'
>>
>> R=pow((pow(10, ref/10))/200,5/8) is formula to convert from Z (dBz) to R
>> (mm/hr)
>> to get value mm/hr, I have to use R/15.
>>
>> Thank you very much.
>>
>> Best regards,
>> wendi
>>
>>
>>
>>
>> On Thu, Jul 12, 2012 at 6:32 AM, Charles Seman <charles.seman at noaa.gov
>> <mailto:charles.seman at noaa.gov>> wrote:
>>
>>      Wendi,
>>
>>      An idea; set the time dimension to span t=1,15 for the definition of
>>      "R":
>>
>>      'set t 1 15'
>>      'R=pow((pow(10, ref/10))/200,5/8)'
>>      'set t 1' ;* see discussion below
>>      'd sum(R, t=1, t=15)'
>>
>>      'set t 1': for displaying sum; this is OK to go from time range to a
>>      single time level to do the sum (see "wild cards" discussion at
>>      http://grads.iges.org/grads/gadoc/variable.html#new); if left as 'set t
>>      1 15', I think you would get 15 time levels with same "sum" result for
>>      the display command... you could try it both ways to see what you get...
>>
>>      Hope this helps,
>>      Chuck
>>
>>      On 07/06/2012 05:53 AM, wendi harjupa wrote:
>>       > Dear Grads users,
>>       >
>>       > I have problem,
>>       > below is  my descriptor file
>>       >
>>       > DSET
>>      /misc/home/wendi/data1/radar/kototabang/XDR/data/20040410/%d2%h2.dat
>>       > TITLE  RADAR
>>       > OPTIONS  TEMPLATE LITTLE_ENDIAN
>>       > UNDEF  -1000
>>       > XDEF    321 LINEAR    99.688120996    0.004492369
>>       > YDEF    321 LINEAR    -1.083708891    0.004522556
>>       > ZDEF    39  LINEAR   1.0 0.5
>>       > TDEF    15 LINEAR 21:00Z10apr2004  4mn
>>       > VARS    2
>>       > ref 39  99  Reflectivity(dBZ)
>>       > vel 39  99  Doppler Velocity(m/s)
>>       > ENDVARS
>>       >
>>       > As you see time is 15,
>>       >
>>       > I want to convert the ref (dbz) to Rain (mm/hr)
>>       > by using Z-R correlation formula, as below :
>>       >
>>       > 'pow((pow(10, R/10))/200,5/8)',
>>       >
>>       > Then I want to accumulate the rainrate for 1 hour,
>>       > I use this formula :
>>       >
>>       > 'sum(ref, t=1, t=15)'
>>       >
>>       > But I got strange result.
>>       >
>>       > Here my complete gs file,
>>       >
>>       > 'reinit'
>>       > 'set grads off'
>>       > 'set mproj latlon'
>>       > 'set mpdset hires'
>>       > 'set gxout shaded'
>>       > 'open RHI.ctl'
>>       > 'set lon 100 100.8'
>>       > 'set lat -0.45'
>>       > 'set Z 1 19'
>>       > 'set parea 1 7.5 2.8 8.3'
>>       > 'set clevs 0 50 100 150 200 250 300 350 400 450 500 550 600'
>>       > 'set ccols 9 14 4 11 5 13 3 10 7 12 8 2 6'
>>       > 'R=pow((pow(10, ref/10))/200,5/8)'
>>       > 'd sum(R, t=1, t=15)'
>>       > 'run /misc/home/wendi/grads-2.0.1/cbarn 0.7 0.7 7.9 5.2'
>>       > 'draw string  7.7 7.8 [dBz]'
>>       >
>>       > Would you help me, about this,
>>       > please let me know, which part I got wrong
>>       >
>>       > Thank you very much!
>>       >
>>       > Best regards,
>>       > wendi
>>       >
>>       >
>>       > --
>>       > -------------
>>       > Wendi Harjupa. ST
>>       > ShimaneUniversityGraduateSchool ofEngineering Sciences
>>       > Department ofElectronic ControlSystems
>>       > RemoteSensingLaboratory
>>       > s119447
>>       > Cellphone : +81-080-4268-6676
>>       > email : wendi at rslab.riko.shimane-u.ac.jp
>>      <mailto:wendi at rslab.riko.shimane-u.ac.jp>
>>       > <mailto:wendi at rslab.riko.shimane-u.ac.jp
>>      <mailto:wendi at rslab.riko.shimane-u.ac.jp>>
>>       >
>>       >
>>       >
>>       > _______________________________________________
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>>       > gradsusr at gradsusr.org <mailto:gradsusr at gradsusr.org>
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>>       >
>>
>>      --
>>
>>      Please note that Charles.Seman at noaa.gov
>>      <mailto:Charles.Seman at noaa.gov> should be considered my NOAA
>>      email address, not cjs at gfdl.noaa.gov <mailto:cjs at gfdl.noaa.gov>.
>>
>>      ********************************************************************
>>         Charles Seman Charles.Seman at noaa.gov <mailto:Charles.Seman at noaa.gov>
>>         U.S. Department of Commerce / NOAA / OAR
>>         Geophysical Fluid Dynamics Laboratory         voice: (609)
>>      452-6547 <tel:%28609%29%20452-6547>
>>         201 Forrestal Road                              fax: (609)
>>      987-5063 <tel:%28609%29%20987-5063>
>>         Princeton, NJ  08540-6649 http://www.gfdl.noaa.gov/~cjs/
>>      ********************************************************************
>>
>>      "The contents of this message are mine personally and do not reflect any
>>      official or unofficial position of the United States Federal Government,
>>      the United States Department of Commerce, or NOAA."
>>
>>
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>>
>>
>>
>>
>> --
>> -------------
>> Wendi Harjupa. ST
>> ShimaneUniversityGraduateSchool ofEngineering Sciences
>> Department ofElectronic ControlSystems
>> RemoteSensingLaboratory
>> s119447
>> Cellphone : +81-080-4268-6676
>> email : wendi at rslab.riko.shimane-u.ac.jp
>> <mailto:wendi at rslab.riko.shimane-u.ac.jp>
>>
>>
>>
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