[gradsusr] TRMM data

Teddy Allen teddyallen at yahoo.com
Wed Jun 6 12:03:57 EDT 2012


Ahsan,
Alternatively, you can use the IRI Climate Library to download TRMM daily as an entire netcdf file from here:
http://iridl.ldeo.columbia.edu/SOURCES/.NASA/.GES-DAAC/.TRMM_L3/.TRMM_3B42/.v6/.daily/.precipitation/
This avoids any sort of control files or concat procedures. I find it to be very easy to use with GrADS.
 
cheers,
teddy 

http://www.teddyallen.com
"To move quickly, go alone. To move far, go together." 
African Proverb
 

________________________________
 From: Syed Ahsan Ali <ahsanshah01 at gmail.com>
To: Zhong Liu <Zhong.Liu-1 at nasa.gov> 
Cc: GrADS Users Forum <gradsusr at gradsusr.org> 
Sent: Wednesday, June 6, 2012 11:46 AM
Subject: Re: [gradsusr] TRMM data
  

Dear Zhong 

While working with the V6 data and referring to the page for conversion of 3-hourly (mm/hr)rainfall to total daily rainfall [http://disc.sci.gsfc.nasa.gov/additional/faq/precipitation_faq.shtml#convert], I concatinated the 3-hourly binary files first and then made a single daily file and used the following command to display the data for a grid point in grads.
 d sum(r*24,t=1,t=8) and it gives me the answer 96. But when I downloaded and displayed the daily rainfall file from the ftp (which is accumulated rainfall as per readme) for the same grid point and the same day it gives 0 answer. While the actual observed rainfall is 116mm. So, where could be the problem. 

Kind Regards 
Ahsan

 
On Wed, Jun 6, 2012 at 8:37 PM, Zhong Liu <Zhong.Liu-1 at nasa.gov> wrote:

Dear Ahsan,
>
>Glad to hear the info is useful.
>
>If you plan to do subsetting of the data, the GrADS way could 
>be useful, especially with GDS and OPeNDAP. You could write a GrADS script to 
>do that as well.
>
>Good luck!
>
>Regards,
>
>-Zhong 
>
>
>On 6/6/2012 11:34 AM, Syed Ahsan Ali wrote: 
>Dear Zhong  
>>
>>Thanks alot for the email. This is great news that V7 is available.  
>>I have tried a simple thing that is concatenation of all files using CAT command in linux to make a single file. I'll also try the method which you have mentioned. 
>>
>>Thank you 
>>Best Regards 
>>Ahsan
>>
>> 
>>On Wed, Jun 6, 2012 at 8:17 PM, Zhong Liu <Zhong.Liu-1 at nasa.gov> wrote:
>>
>>Dear Ahsan,
>>>
>>>Dr. Lynnes forwarded your question to me.
>>>
>>>First, V7 TRMM 3B42 and its daily have just been released. Please use them if possible,
>>>
>>>ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/3B42_V7 ( for 3 hourly)
>>>ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/Derived_Products/3B42_V7/Daily (daily)
>>>
>>>To aggregate files, I have an example below.
>>>
>>>Please note that the similar method can be applied to GDS, OPeNDAP, or binary files (listed in the above
>>>directories).
>>>
>>>Hope these help.
>>>
>>>Regards,
>>>
>>>-Zhong
>>>
>>>ga-> open 3b42_netcdf.ctl
>>>Scanning description file:  3b42_netcdf.ctl
>>>Data file 3B42.%y2%m2%d2.%h1.6A.nc is open as file 1
>>>LON set to 0 360
>>>LAT set to -49.875 49.875
>>>LEV set to 1000 1000
>>>Time values set: 1998:1:1:0 1998:1:1:0
>>>ga-> set time 18z1apr2010 0z2apr2010
>>>Time values set: 2010:4:1:18 2010:4:2:0
>>>ga-> define rtmp=r
>>>Define memory allocation size = 6921600 bytes
>>>ga-> set fwrite test.bin
>>>FWrite file name = test.bin
>>>FWwrite byte order is little_endian; format is stream
>>>Fwrite replacing an existing file if it exist
>>>ga-> set gxout fwrite
>>>ga-> d rtmp
>>>Wrote 576800 of 576800 elements to test.bin as Stream Little_Endian
>>>Wrote 576800 of 576800 elements to test.bin as Stream Little_Endian
>>>Wrote 576800 of 576800 elements to test.bin as Stream Little_Endian
>>>Press enter to continue:::::
>>>ga-> disable fwrite
>>>
>>>where 3b42_netcdf.ctl is,
>>>
>>>dset ^3B42.%y2%m2%d2.%h1.6A.nc
>>>dtype netcdf
>>>options template
>>>title TRMM 3B42 V6 three hourly TRMM rainfall
>>>undef -9999.9
>>>xdef 1440 linear -179.875 0.25000000
>>>ydef 400  linear -49.8750000 0.25000000
>>>zdef 1 levels 1000
>>>tdef 41384 linear 00:00Z01jan1998 3hr
>>>* end_time 21:00Z29feb2012 (this_is_comment_line)
>>>vars 2
>>>precipitation=>r      0  y,x Hourly Rain Rate (mm/hr)
>>>relativeError=>err    0  y,x Error (mm/hr)
>>>endvars
>>>
>>>and to test the output file, use this ctl,
>>>
>>>dset test.bin
>>>title TRMM 3B42 V6 three hourly TRMM rainfall
>>>undef -9999.9
>>>xdef 1440 linear -179.875 0.25000000
>>>ydef 400  linear -49.8750000 0.25000000
>>>zdef 1 levels 1000
>>>tdef 39432 linear 00:00Z01jan1998 3hr
>>>* end_time 21:00Z30jun2011 (this_is_comment_line)
>>>vars 1
>>>r         0   99 Hourly Rain Rate (mm/hr)
>>>endvars
>>>
>>>
>>>
>>>
>>>On 6/5/2012 7:53 AM, Lynnes, Christopher S. (GSFC-6102) wrote:
>>>
>>>On Jun 5, 2012, at 7:47 AM, Christopher Lynnes wrote:
>>>>
>>>>
>>>>Is this something that can be solved by our GDS server for this user?
>>>>>I'm thinking of: http://disc2.nascom.nasa.gov/dods/3B42RT.info
>>>>
>>>>But I don't know how to aggregate to a time series using GrADS.  It must be possible…
>>>>
>>>>
>>>>Begin forwarded message:
>>>>>
>>>>>
>>>>>From: Syed Ahsan Ali<ahsanshah01 at gmail.com>
>>>>>>Subject: Re: [gradsusr] TRMM data
>>>>>>Date: June 5, 2012 3:53:14 AM EDT
>>>>>>To: GrADS Users Forum<gradsusr at gradsusr.org>
>>>>>>Reply-To: GrADS Users Forum<gradsusr at gradsusr.org> 
>>>>>>
>>>>>>
>>>>>>Dear  Jayakrishnan,
>>>>>> I have downloaded the 3-hourly nc files and also had a plan to concatenate all of them, but the problem was that there is no date information in the file so when I'll concatenate there would be a mess up. Thanks for the link. But I don't know how to combine these binary files. Any hint for this.
>>>>>>
>>>>>>Best Regards
>>>>>>Ahsan
>>>>>>
>>>>>>On Tue, Jun 5, 2012 at 10:08 AM, Jayakrishnan P.R<prjayakrishnan at gmail.com>  wrote:
>>>>>>Dear Ahsan,
>>>>>>             I think you downloaded the single nc file from mirador search. It will contain only sinlgle time data in each 3 hour. To have a time series of data you will have to concatenate the data files. There is another simple site to download the binary files of TRMM three hourly as well as daily. You can download the data from this alternate site and combine the data files and write a corresponding ctl file.
>>>>>>
>>>>>>This is the link for TRMM data
>>>>>>
>>>>>>ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/3B42_V6 ( for 3 hourly)
>>>>>>ftp://disc2.nascom.nasa.gov/data/TRMM/Gridded/Derived_Products/3B42_V6/Daily (daily)
>>>>>>
>>>>>>
>>>>>>Best of luck.....
>>>>>>-- 
>>>>>>Sincerely
>>>>>>***********************************************
>>>>>>Jayakrishnan.P.R
>>>>>>CSIR-Senior Research Fellow
>>>>>>Department of Atmospheric Sciences
>>>>>>Cochin University of Science and Technology (CUSAT), Cochin-682 016
>>>>>>Kerala, India.
>>>>>>Mob: 09895417565
>>>>>>
>>>>>>***********************************************
>>>>>>
>>>>>>_______________________________________________
>>>>>>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
>>>>>> --
>>>>>Dr. Christopher Lynnes, NASA/GSFC, Code 610.2, 301-614-5185
>>>>>
>>>>>--
>>>>Dr. Christopher Lynnes, NASA/GSFC, Code 610.2, 301-614-5185
>>>>
>>>>
>>>
>>>-- 
>>>Zhong Liu, Ph.D.
>>>Zhong.Liu-1 at nasa.gov
>>>George Mason University and
>>>NASA Goddard Earth Sciences Data and
>>>Information Services Center
>>>NASA/GSFC, Code 610.2
>>>Greenbelt. MD. 20771  U.S.A.
>>>(301) 614-5764 (voice)
>>>(301) 614-5268 (fax)
>>>http://disc.gsfc.nasa.gov
>>>http://disc2.nascom.nasa.gov/Giovanni/tovas/
>>>http://disc.sci.gsfc.nasa.gov/hurricane/trmm_quikscat_analysis.shtml
>>>http://disc.sci.gsfc.nasa.gov/agriculture/ais_sup/current_conditions.shtml
>>>
>>>
>> 
>
>
>-- 
Zhong Liu, Ph.D. Zhong.Liu-1 at nasa.gov George Mason University and
NASA Goddard Earth Sciences Data and
Information Services Center
NASA/GSFC, Code 610.2
Greenbelt. MD. 20771  U.S.A.
(301) 614-5764 (voice)
(301) 614-5268 (fax) http://disc.gsfc.nasa.gov http://disc2.nascom.nasa.gov/Giovanni/tovas/ http://disc.sci.gsfc.nasa.gov/hurricane/trmm_quikscat_analysis.shtml http://disc.sci.gsfc.nasa.gov/agriculture/ais_sup/current_conditions.shtml 


-- 
Syed Ahsan Ali Bokhari 
Electronic Engineer (EE) 

Research & Development Division
Pakistan Meteorological Department H-8/4, Islamabad.
Phone # off  +92518358714 
Cell # +923155145014


_______________________________________________
gradsusr mailing list
gradsusr at gradsusr.org
http://gradsusr.org/mailman/listinfo/gradsusr
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20120606/c3deea6b/attachment-0003.html 


More information about the gradsusr mailing list