Re: MOD16 HDF files

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Thu Apr 17 2014 - 07:22:49 MDT

The following MOD16 related questions were sent offline.
They are being redirected to ncl-talk

[1]
I am trying to regrid the MOD16 ET data (http://www.ntsg.umt.edu/modis)
into the rectilinear format. In order to do this I need the lat and lon
from the source datasets. But somehow the source data doesn't have the lat
and lon in degrees, but is a projected geo frame, with four corner points
specified with both lat and lon and in meters and the resolution provided
in 1km. In this way, is there anybody know how to generate the lat and lon
from this coordinate system? Attached is the ncl_filedump for the source
mod16 ET datasets(it is really too long to paste here).

Thank you in advance for any possible help.

[2]
Here comes the new question that I thought you might be a little bit more
familiar with the modis data regridding process.

The lat and lon I got from the .he2 file are in 2 dimensions, but when I
assign it to the source grid variables, it always returns an error saying
coordinate variables can only be one dimensional. In this case, what should
I do to apply the lat and lon coordinates to the source grids then I can do
the regridding with ESMF_regrid?

Thank you very much in advance.
=========================================================================
Response:
=========================================================================
[1] Please download 6.2.0: http://www.ncl.ucar.edu/Download/

[2] MOD16 files are HDF-EOS. When accessing the file append
     a '.he' extension. NCL will read the .hdf and .he2
     information and combine them.

     %> ncl_filedump MOD16A2....hdf.he2 | less

       fil = "MOD16A2....hdf"
       f = addfile(fili+".he2", "r") ; append .he2
       print(f)

[3] NCL will provide the appropriate lat and lon variables.
     In MOD16 files these are two dimensional

[4] Only one MOD16 file was available locally but every variable
     on the file had missing values. ncl-talk is not going to
     go to various websites to download files. If you need to
     send a sample file

ftp ftp.cgd.ucar.edu
anonymous
<use your email address for the password>
cd incoming
put ...
put ...
.
.
.
quit

Note that for security reasons, you cannot list the contents of this
directory,
and neither can we. We need to know the exact names of the files in
order to retrieve them.

[5] A sample read/plot script that may work is attached.
     Your variables may have different names.

[6] See ESMF Regridding examples: 5, 8 and 15

     If the grid is always the same. Generate the weight file once

>> --
>> Lisi Pei
>> --------------------------
>> Research Scholar
>> Department of Geography,Michigan State University
>> East Lansing,MI,48823
>> PhD. Candidate
>> Institute of Atmospheric Physics,Chinese Academy of Sciences
>> Beijing,China,100029

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Received on Thu Apr 17 07:23:01 2014

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