[gradsusr] Need Help for specific command

Rashed Mahmood rashidcomsis at gmail.com
Thu Nov 5 12:54:27 EST 2015 

Well...There are a number of potential issues in your script. i am have not
used grads for a long period so may be i won't be able help much.
However, here are some of the things that looked odd to me.

"reinit"
"sdfopen \Users\mq43879691\documents\sst5014.mnmean.v4.nc"

"set t 1 12"        ** i do not know why you keep on changing this time
settings.*


"define avesst=ave(sst2,t+0,t=780,12)"
"modify avesst seasonal"

"set t 1 780"                          * * again, i am not sure how would
this work as your avesst is now seasonal mean?  *
"define sstanom=sst2-avesst"

"define N4=aave(sstanom,lon=160,lon=210,lat=-5,lat=5)"
"define N3=aave(sstanom,lon=210,lon=270,lat=-5,lat=5)"
"define prod = N3*N4"

if ( prod > 0)
   alpha = 0.4
 else
  alpha = 0
endif

"define Nct = N3-alpha*N4"
"define Nwp = N4-alpha*N3"

"set lev 0"                                           ** why are these
settings needed? should'nt it be something like 'set x 1 and set y 1'?*
"set lon 210"                                        ** you have already
done area average so where would this come from? *
"set lat -5"                                           ** same as above*
"set timelab off"
"set Grads off"
"set cmark 0"
"set t 1 780"                                       **oh well...same as
above*
"d Nct"

Perhaps there are other issues for example the defining of
'sstanom=sst2-avesst'.










On Wed, Nov 4, 2015 at 5:34 PM, MD ABDUS SATTAR <
md-abdus.sattar at students.mq.edu.au> wrote:

> Dear Rashed
> Thank you very much for your cooperation. I am still in trouble to
> calculate this. See my script my as follow:
>
> "reinit"
> "sdfopen \Users\mq43879691\documents\sst5014.mnmean.v4.nc"
> "set t 1 12"
> "define avesst=ave(sst2,t+0,t=780,12)"
> "modify avesst seasonal"
> "set t 1 780"
> "define sstanom=sst2-avesst"
>
> "define N4=aave(sstanom,lon=160,lon=210,lat=-5,lat=5)"
> "define N3=aave(sstanom,lon=210,lon=270,lat=-5,lat=5)"
> "define prod = N3*N4"
>
> if ( prod > 0)
>    alpha = 0.4
>  else
>   alpha = 0
> endif
>
> "define Nct = N3-alpha*N4"
> "define Nwp = N4-alpha*N3"
>
> "set lev 0"
> "set lon 210"
> "set lat -5"
> "set timelab off"
> "set Grads off"
> "set cmark 0"
> "set t 1 780"
> "d Nct"
>
> >From the above script I was trying to calculate time series of Nct and
> Nwp during 1950-2014. Nct and Nwp have single values for each month
> (January to December). If i can use this command for yearly time series
> then I can use it for monthly time series as well.
>
> Please suggest me where I did mistake again.
>
> I look forward to your message
>
> Regards
> Abdus
>
>
>
>
> On Wed, Nov 4, 2015 at 8:28 AM, Rashed Mahmood <rashidcomsis at gmail.com>
> wrote:
>
>> The way you wrote it, won't work because this is not how "if else endif"
>> statements are used .
>> Please see the following page for a detailed information on statements:
>>
>> http://iges.org/grads/gadoc/script.html#statement
>>
>> Assuming that your N3 and N4 are defined (have a single value each)
>> before the following:
>> Try this:
>>
>>
>> 'prod = N3*N4'
>>
>> if ( prod > 0)
>>    alpha = 0.4
>>  else
>>   alpha = 0
>> endif
>>
>> 'Nct = N3-alpha*N4'
>> 'Nwp = N4-alpha*N3'
>>
>>
>> And you can use it inside a loop to calculate for a time series.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Mon, Nov 2, 2015 at 7:57 PM, MD ABDUS SATTAR <
>> md-abdus.sattar at students.mq.edu.au> wrote:
>>
>>> Dear Rashed
>>> I wrote my script as:
>>>
>>> "define prod=N3*N4"
>>> "define alpha=0.4,if(prod>0)"
>>> "define alpha=0, if (prod<0)"
>>> "endif"
>>> "define Nct=N3-alpha*N4"
>>> "define Nwp=N4-alpha*N3"
>>>
>>> However, it does not work and I do not know my mistake here. I am
>>> using NOAA Extended Reconstructed Sea Surface Temperature (SST) V4 data (
>>> http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.v4.html).
>>>
>>> Could please tell me where I did mistake?
>>>
>>> I look forward to your message.
>>>
>>> Cheers
>>> Abdus Sattar
>>>
>>>
>>> On Tue, Nov 3, 2015 at 12:27 PM, Rashed Mahmood <rashidcomsis at gmail.com>
>>> wrote:
>>>
>>>> It should be simple using if else statement.
>>>> Untested:
>>>>
>>>> prod = N3*N4
>>>>
>>>> if ( prod > 0)
>>>>    alpha = 0.4
>>>>  else
>>>>   alpha = 0
>>>> endif
>>>>
>>>> Nct = N3-alpha*N4
>>>> Nwp = N4-alpha*N3
>>>>
>>>> hope that helps
>>>>
>>>>
>>>>
>>>> On Mon, Nov 2, 2015 at 4:52 PM, MD ABDUS SATTAR <
>>>> md-abdus.sattar at students.mq.edu.au> wrote:
>>>>
>>>>> Dear Team
>>>>> I was trying to calculate year by year time series from monthly mean
>>>>> SST data by using following formula:
>>>>>
>>>>> [image: Inline image 1]
>>>>> Where, N3 and N4 denote Nino3 and Nino4 indices respectively. I would
>>>>> like to calculate NCT and NWP for a specific year, for instance, 1997
>>>>> (January to December). My question is how can I define "α
>>>>>
>>>>> value" in GrADS so that it can use the value of 2/5 or 0
>>>>> automatically? If anybody could help me, it would be great.
>>>>>
>>>>> I look forward to your message.
>>>>>
>>>>> Best regards
>>>>> Abdus
>>>>> --
>>>>> Md. Abdus Sattar
>>>>> PhD Student
>>>>> Department of Environmental Sciences
>>>>> Level 2, Australian Hearing Hub Building
>>>>>
>>>>> Faculty of Science and Engineering
>>>>> Macquarie University
>>>>> NSW 2109 Australia
>>>>>
>>>>>
>>>>> Cell: +61404400401
>>>>> Email: md-abdus.sattar at students.mq.edu.au
>>>>>
>>>>> *AND*
>>>>>
>>>>> Assistant Professor
>>>>> Department of Disaster Risk Management (DRM)
>>>>> Faculty of Disaster Management
>>>>> Patuakhali Science and Technology University, Dumki, Patuakhali,
>>>>> Bangladesh
>>>>>
>>>>> Cell: +8801716851612
>>>>> Email: abdus.sattar at pstu.ac.bd
>>>>>
>>>>> _______________________________________________
>>>>> gradsusr mailing list
>>>>> gradsusr at gradsusr.org
>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> gradsusr mailing list
>>>> gradsusr at gradsusr.org
>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>
>>>
>>> --
>>> Md. Abdus Sattar
>>> PhD Student
>>> Department of Environmental Sciences
>>> Level 2, Australian Hearing Hub Building
>>>
>>> Faculty of Science and Engineering
>>> Macquarie University
>>> NSW 2109 Australia
>>>
>>>
>>> Cell: +61404400401
>>> Email: md-abdus.sattar at students.mq.edu.au
>>>
>>> *AND*
>>>
>>> Assistant Professor
>>> Department of Disaster Risk Management (DRM)
>>> Faculty of Disaster Management
>>> Patuakhali Science and Technology University, Dumki, Patuakhali,
>>> Bangladesh
>>>
>>> Cell: +8801716851612
>>> Email: abdus.sattar at pstu.ac.bd
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
>
> --
> Md. Abdus Sattar
> PhD Student
> Department of Environmental Sciences
> Level 2, Australian Hearing Hub Building
>
> Faculty of Science and Engineering
> Macquarie University
> NSW 2109 Australia
>
>
> Cell: +61404400401
> Email: md-abdus.sattar at students.mq.edu.au
>
> *AND*
>
> Assistant Professor
> Department of Disaster Risk Management (DRM)
> Faculty of Disaster Management
> Patuakhali Science and Technology University, Dumki, Patuakhali, Bangladesh
>
> Cell: +8801716851612
> Email: abdus.sattar at pstu.ac.bd
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>
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