[gradsusr] TRMM data

Wed Jun 6 11:17:36 EDT 2012

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
>>>
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
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>> --
>> 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