[gradsusr] Defining Nino Regions
Andrew Friedman
andfried at gmail.com
Sun Sep 27 05:53:36 EDT 2015
Hi Abdus,
Can you please post your script and the messages you receive at the specific lines?
Andrew
> On Sep 27, 2015, at 10:52 AM, MD ABDUS SATTAR <md-abdus.sattar at students.mq.edu.au> wrote:
>
> Dear Andrew and Jim
> I am still fighting in defining different nino regions in GrADS. I am using sst data from http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.ersst.v4.html in where -
> Spatial Coverage:
> • 2.0 degree latitude x 2.0 degree longitude global grid (89x180).
> • 88.0N - 88.0S, 0.0E - 358.0E
> When I define nino4 = aave(sstanom,lon=160,lon=210,lat=-5,lat=5) then it seems to working (see the attached file). However, when I used Jim's first suggestion, then the GrADS says "Entire Grid Undefined" and output from his 2nd suggestion does not comparable to other sources (e.g. http://www.esrl.noaa.gov/psd/data/climateindices/. I could not identify my problems. If you could help me in defining Nino 4, 3.4, 3 and central pacific Nino then it would be very helpful for me.
>
> Thanking you
>
> Abdus
>
>
> On Fri, Sep 25, 2015 at 8:55 PM, Andrew Friedman <andfried at gmail.com> wrote:
> Hi Abdus,
>
> There are two issues here:
>
> (1) Your nino index longitudes are still not defined correctly. I believe that you want degrees west, but what you have written is for degrees east (the convention is that positive longitude is east and negative longitude is west). How you set up the averaging across the date line depends on how your dataset is formatted. Please see Jim's recent emails for how to set this up.
>
> (2) For your climatology, I think that your original sequence should create climatologies for each month:
>
> "set t 1 12"
> "define avesst=ave(sst1,t+0,t=432,12)"
> "modify avesst seasonal"
> "set t 1 432
>
> In other words, I think that avesst at t=2 should be the February climatology.
>
> Best, Andrew
>
> On Fri, Sep 25, 2015 at 6:31 AM, MD ABDUS SATTAR <md-abdus.sattar at students.mq.edu.au> wrote:
> Dear Andrew and Jim
> I am still a bit confused for defining the El Nino regions. Shall I define as:
>
> "define nino34=aave(sstanom,lon=120,lon=170,lat=-5,lat=5)"
> "define nino3=aave(sstanom,lon=90,lon=150,lat=-5,lat=5)"
> "define ninocp (central pacific)=aave(sstanom,lon=120,lon=160,lat=-5,lat=5)"
>
> Andrew, I have time frame of my data monthly mean from 1979/Jan(1) to 2014/Dec(432) and set as follows:
> "set t 1 12"
> "define avesst=ave(sst1,t+0,t=432,12)"
> "modify avesst seasonal"
> "set t 1 432"
>
> Therefore, this command calculate only the Jan months average sst from 1979-2014 as our first time data is from 1979/Jan. Now I would like to create climatology for February month. I have just changed as "define avesst=ave(sst1,t=1,t=432,12)". But I think there is a mistake as the index is not comparable to other sources.
>
> Could you please clarify me in these regards?
>
> I am really highly appreciate to your cooperation.
>
> Regards
> Abdus
>
>
> On Fri, Sep 25, 2015 at 8:34 AM, Andrew Friedman <andfried at gmail.com> wrote:
> Thank you, Jim.
> -Andrew
>
>
>
> On Sep 24, 2015, at 9:10 PM, James T. Potemra <jimp at hawaii.edu> wrote:
>
>> Hi Andrew,
>>
>> Actually, if you can redefine the longitudes in your control file from (-180:180) to (0:360)
>> that would solve the dateline issue. In this case you could have aave(sstanom,lon=160,lon=210....
>> to resolve to 160E to 150W.
>>
>> In order to go beyond 360 (e.g., lon=340,lon=390), your data set has to be continuous in
>> the sense that 361 (or whatever) is a legitimate extension. For example, if you start at 0
>> and go to 359 increment by 1, the next point would be 360 (0), then 361 (1), etc. To check
>> you can try make a global plot of some variable, and set the longitude range from 0 to 720;
>> in this case you should either see a twice-global plot.
>>
>> Jim
>>
>> On 9/24/15 12:24 AM, Andrew Friedman wrote:
>>> Thank you for these clarifications, Jim.
>>>
>>> To follow up:
>>> To use your suggested option (2), "define nino4 = aave(sstanom,lon=340,lon=390,lat=-5,lat=5)"
>>>
>>> Would I first need to redefine the longitude values
>>> 'set lon 0 360' ?
>>>
>>> Best,
>>> Andrew
>>>
>>> On Thu, Sep 24, 2015 at 4:45 AM, James T. Potemra <jimp at hawaii.edu> wrote:
>>> Hi Abdus/Andrew,
>>>
>>> I'd be cautious of your nino4 as defined. I presume your data are defined -180 to 180, where eastern longitudes are 0 to 180 and western longitudes are -180 to 0. In your line:
>>>
>>> "define nino4=aave(sstanom,lon=-150,lon=160,lat=-5,lat=5)”
>>>
>>> the longitudes are in fact ascending (-150 is less than 160), however I believe this will create a mean from 150W eastward all the way around to 160E (again, assuming your longitudes are defined -180 to 180), a mean over 310 longitudes. Instead you want 160E to 150E, or a mean over 50 longitudes. I further think Andrew's suggestion
>>>
>>> "define nino4=aave(sstanom,lon=160,lon=-150,lat=-5,lat=5)”
>>>
>>> will give an operation error (min lon > max lon).
>>>
>>> Instead you could try either:
>>>
>>> 1. define two different boxes across the dateline:
>>> define nino4a = aave(sstanom,lon=160,lon=180,lat=-5,lat=5)
>>> define nino4b = aave(sstanom,lon=-180,lon=-150,lat=-5,lat=5)
>>> define nino4 = ( 20 * nino4a + 30 * nino4b ) / 50.0
>>>
>>> 2. if the file is global and continuous, you might be able to use
>>> define nino4 = aave(sstanom,lon=340,lon=390,lat=-5,lat=5)
>>>
>>> Jim
>>>
>>>
>>> On 9/22/15 4:41 PM, MD ABDUS SATTAR wrote:
>>>> Hi Andrew
>>>> Thanks!
>>>>
>>>> On Wed, Sep 23, 2015 at 5:58 AM, Andrew Friedman <andfried at gmail.com> wrote:
>>>> Hi Abdus,
>>>>
>>>> I think that you are setting up the anomalies correctly. However, you may have a problem with your NINO4 domain:
>>>> > "define nino4=aave(sstanom,lon=-150,lon=160,lat=-5,lat=5)”
>>>>
>>>> https://climatedataguide.ucar.edu/climate-data/nino-sst-indices
>>>>
>>>> In GrADS, longitudes need to be ascending.
>>>>
>>>> I think that you want to reverse your longitudes so you have
>>>>
>>>> "define nino4=aave(sstanom,lon=160,lon=-150,lat=-5,lat=5)” OR "define nino4=aave(sstanom,lon=160,lon=210,lat=-5,lat=5)”
>>>>
>>>> Best, Andrew
>>>>
>>>> > On Sep 22, 2015, at 7:57 AM, MD ABDUS SATTAR <md-abdus.sattar at students.mq.edu.au> wrote:
>>>> >
>>>> > Dear Andrew
>>>> > Thank you very much for your previous suggestion. Now, I can prepare El Nino series as well as temporal correlation. However, I am not confident enough whether I am right or wrong. I use the following script for correlating El Nino 4 index with sea level pressure (Jan 1979 to Dec2014). Please confirm me the following command.
>>>> > "reinit"
>>>> > "sdfopen \Temp\sst7914.mnmean.v4.nc"
>>>> > "set t 1 12"
>>>> > "define avesst=ave(sst1,t+0,t=432,12)"
>>>> > "modify avesst seasonal"
>>>> > "set t 1 432"
>>>> > "define sstanom=sst1-avesst"
>>>> >
>>>> > "define nino4=aave(sstanom,lon=-150,lon=160,lat=-5,lat=5)"
>>>> >
>>>> > "sdfopen \Users\mq43879691\documents\test2\mslp.mon.mean.nc"
>>>> > "set lon 0 360"
>>>> > "set lat -90 90"
>>>> > "set t 1"
>>>> > "d tcorr(nino4,mslp.2,t=1,t=432)"
>>>> >
>>>> > Output:
>>>> > <image.png>
>>>> >
>>>> > How can perform lead or lag correlation?
>>>> >
>>>> > Best regards
>>>> > Abdus
>>>> >
>>>> > On Tue, Sep 15, 2015 at 6:48 AM, Andrew Friedman <andfried at gmail.com> wrote:
>>>> > Hi Abdus,
>>>> >
>>>> > Your timeseries is static because your boundaries for ssta do not have a time-varying dimension.
>>>> >
>>>> > There are different commands, depending on what you’re trying to do.
>>>> >
>>>> > Are you trying to create a monthly ssta climatology? If so, check out the instructions for the command ‘modify’: http://www.iges.org/grads/gadoc/gradcomdmodify.html
>>>> >
>>>> > Or are you trying to create a running mean timeseries of ssta? In that case, try something like ssta=ave(sst,t-11,t+0).
>>>> >
>>>> > Best,
>>>> > Andrew
>>>> >
>>>> >
>>>> > On Sep 13, 2015, at 8:01 AM, MD ABDUS SATTAR <md-abdus.sattar at students.mq.edu.au> wrote:
>>>> >
>>>> > > Hi Andrew
>>>> > > I was trying to set tloop, but still facing difficulties. I prepared the script as:
>>>> > > "reinit"
>>>> > > "sdfopen \Users\mq43879691\documents\test2\sst.mnmean.v4.nc"
>>>> > > "set t 1 1937"
>>>> > > "define ssta=ave(sst,t=1501,t=1933,12)"
>>>> > >
>>>> > > "set lat 25"
>>>> > > "set lon 50"
>>>> > > "set lev 0"
>>>> > > "set t 1501 1933"
>>>> > >
>>>> > >
>>>> > > "d tloop(aave(ssta,lon=100,lon=170,lat=-5,lat=5))"
>>>> > >
>>>> > > "d tloop(aave(sst,lon=100,lon=170,lat=-5,lat=5))"
>>>> > >
>>>> > > I can display time series of El Nino by using sst value ("d tloop(aave(sst,lon=100,lon=170,lat=-5,lat=5))"). However, I would like use to ssta ("d tloop(aave(ssta,lon=100,lon=170,lat=-5,lat=5))") and when I use this the following map is found. Could you please suggest me in this regards?
>>>> > >
>>>> > >
>>>> > >
>>>> > > <image.png>
>>>> > >
>>>> > >
>>>> > > Thanking you
>>>> > >
>>>> > > Abdus
>>>> > >
>>>> > >
>>>> > >
>>>> > > On Fri, Sep 11, 2015 at 4:18 PM, Andrew Friedman <andfried at gmail.com> wrote:
>>>> > > Hi Abdus,
>>>> > > You may need to use ‘tloop’ with aave: http://www.iges.org/grads/gadoc/gradfunctloop.html
>>>> > > Andrew
>>>> > >
>>>> > > On Sep 11, 2015, at 7:05 AM, MD ABDUS SATTAR <md-abdus.sattar at students.mq.edu.au> wrote:
>>>> > >
>>>> > > > Dear GrADS Team
>>>> > > > I am trying to calculate time series of El Nino SST anomaly in January for a specific time period.
>>>> > > >
>>>> > > > I wrote my script as:
>>>> > > >
>>>> > > > "reinit"
>>>> > > > "sdfopen \Users\mq43879691\documents\test2\sst.mnmean.v4.nc"
>>>> > > > "set lon 100"
>>>> > > > "set lat 25"
>>>> > > > "set z 1"
>>>> > > > "set t 1 600"
>>>> > > >
>>>> > > > "define ssta=ave(sst,t=1,t=600,12)"
>>>> > > >
>>>> > > > "define elnino = aave(ssta,lon=100,lon=170,lat=-5,lat=5)"
>>>> > > >
>>>> > > > "d elnino"
>>>> > > >
>>>> > > > The GrADS did not know show anything by this script. On the other hand, when I display only ssta setting lon 50 100 and lat 0 25; then it shows the ssta. Can anybody help me in this regards?
>>>> > > >
>>>> > > > I look forward to your suggestion.
>>>> > > >
>>>> > > > 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
>>>> > > > _______________________________________________
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>>>> > >
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>>>> > >
>>>> > >
>>>> > > --
>>>> > > 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
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>>>> > 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
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>>>>
>>>>
>>>> --
>>>> 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
>>>>
>>>>
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>
>
> --
> 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
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