Introduction

This practice is to help first-time BUFR users to start compiling and running BUFR processing code.

Getting the Sample Codes

Please go to Examples/basic to download the first two examples and its BUFR table to a location space:

• encode_temperature.f90
• decode_temperature.f90
• bufrtable.txt

Here we assume the above files have be copied to a directory under comGSI/util/test. So the BUFRLIB library is located at ../../lib/libbufr_i4r8.a related to this test directory.

Encode/Write to a BUFR file

This example is to open a BUFR file called "t.bufr" and write a temperature observation 10.15 into it. We can use the following two steps to compile the code:

pgf90 -c encode_temperature.f90
pgf90 -o encodeT.exe encode_temperature.o -L../../lib -lbufr_i4r8

 

User may notice that these two steps are standard fortran code compiling process. The special point of the compiling BUFR code is to link the BUFRLIB library at the link step.

 

Also, please note we are using PGI compiler here as an example. Users should use the same compiler as used for compiling BUFRLIB or community GSI.

After got the executable encodeT.exe. We can run it as:

./encodeT.exe

A new BUFR file called "t.bufr" will show up in the working directory. Please note that the BUFR encoding needs an existing BUFR table, which is text file bufrtable.txt we have downloaded with the code and saved in the same directory.

Decode/Read from a BUFR file

This example is to read the temperature observation 10.15 out from the BUFR file "t.bufr", which we created in the practice before. We can use the same two steps to compile the code:

pgf90 -c decode_temperature.f90
pgf90 -o decodeT.exe decode_temperature.o -L../../lib -lbufr_i4r8

After got the executable decodeT.exe. We can run it as:

./decodeT.exe

A line will show up on screen to give the temperature observation that just reading in:

10.10000000000000

Introduction

This practice is to learn the use of the BUFR tools within the community GSI release version 3. The practice is adopted from the similar exercise for the Summer 2011 Tutoral.

Building the Sample Codes

The source code for this exercise is contained in the community GSI package under directory: comGSI_v3/util/bufr_tools . Or you can download the single file from: Examples. For practice, you should have already compiled the community GSI release version 3.0, which gave a BUFRLIB library. The source code for the BUFR tools should then be located in: comGSI_v3/util/bufr_tools

Now, user can following the next two steps to compile all the examples:

1. Change into the comGSI/util/bufr_tools
2. Compile the source: ./make

During compiling, the following message will show up on screen and repeat for each BUFR files:

pgf90 -O2 -c bufr_encode_sample.f90
pgf90 -o bufr_encode_sample.exe -O2 bufr_encode_sample.o -L../../lib -lbufr_i4r8
rm bufr_encode_sample.o

The users can compile a single file using the above compile command.

Once compiled, you will see 10 executables, with .exe suffixes. There are two sets of executables:

The first set ends with the _sample suffix. These codes illustrate basic code structures of fortran code for BUFR file encoding, decoding, and appending:

• bufr_encode_sample.exe
• bufr_decode_sample.exe
• bufr_append_sample.exe

The second set either starts with the prepbufr_ prefix or the _radiance suffix, and is an extension of the first set to PrepBUFR and/or radiance BUFR files.

The second group of codes illustrates how to process BUFR/PrepBUFR files that GSI can use:

• prepbufr_encode_upperair.exe
• prepbufr_encode_surface.exe

• prepbufr_decode_all.exe
• bufr_decode_radiance.exe

• prepbufr_append_upperair.exe
• prepbufr_append_surface.exe
• prepbufr_append_retrieve.exe

Running the simple examples

To illustrate the processing of BUFR/PrepBUFR files, consider the following three simple examples:

• Running ./bufr_encode_sample.exe generates a bufr file named sample.bufr, which includes a single observation.
• Running: ./bufr_decode_sample.exe reads the bufr file sample.bufr, and displays the single observation in it. when run it should display:

  2008120100 1 ADPUPA
1 1 75.0 30.0 -0.1 287.1

• Running the code ./bufr_append_sample.exe appends a new observation to sample.bufr.
• Now running ./bufr_decode_sample.exe a second time, will show that a second observation has been appended to the file sample.bufr by running ./bufr_append_sample.exe .

  2008120100 1 ADPUPA
1 1 75.0 30.0 -0.1 287.1
2008120101 2 ADPSFC
1 1 85.0 50.0 0.2 300.0

Running the BUFR/PrepBUFR samples

The exact same steps can be taken with the PrepBUFR executables.

• Running ./prepbufr_encode_upperair.exe generates a PrepBUFR file prepbufr, which includes a sounding observation.
• Running ./prepbufr_decode_all.exe reads the observations from the file prepbufr, and displays the observation information. Please compare your standard out with that at the link. Notice that two observations have been appended to the file.

• Running ./prepbufr_append_surface.exe appends a surface observation to the PrepBUFR file prepbufr.
• Running ./prepbufr_decode_all.exe reads the observations from the file prepbufr, and displays the observation information. Please compare your standard out with that at the link. Note that the two new surface observations have been added to the file.

• Running ./prepbufr_encode_surface.exe will encode the PrepBUFR file prepbufr with a completely new surface observation, wiping out the previous observations. Check this by running ./prepbufr_decode_all.exe.
• Likewise, running ./prepbufr_append_upperair.exe will append a sounding observation to the file prepbufr. Once again, running ./prepbufr_decode_all.exe display the contents of PrepBufr file. Please compare your standard out with that at the link.

• To append a retrieved data to an existing PrepBUFR file, we can use ./prepbufr_append_retrieve.exe. Once again, use ./prepbufr_decode_all.exe to check the content. The correct output is here.

Please pay attention to the the message type in the BUFR file. This indicates the observation type. Running ./prepbufr_decode_all.exe and ./bufr_decode_radiance.exe can be used to check the content of the real BUFR/PrepBUFR files, with the difference being that these executables dump out a greater amount of information than the sample files.

 

Introduction

This practice is to provide more detailed practices for users who need to work with GSI on observation ingesting from BUFR files.

Get the Codes and compile

Please go to the Examples/GSI BUFR Interface to download the four GSI BUFR interface files to a location space:

• read_prepbufr.f90
• read_gps.f90
• read_bufrtovs.f90
• read_airs.f90

If user put the above files in a directory called ./util/GSI_bufr_interface under the GSI main directory of the release version 3.0. Then, please download this makefile and save it in directory: ./util/GSI_bufr_interface. User can compile these four fortran files using:

./make

Here we assume users have compiled community GSI version 3.0.
If users use other directories other than the above suggested, the makefile needs to be modified to link to the right BUFRLIB library and GSI include files.

Once compiled, 4 executables will show up in working directory:

• read_airs.exe
• read_bufrtovs.exe
• read_gps.exe
• read_prepbufr.exe

Try with NCEP BUFR files

Users can use observation files (here (272M)) for GSI tutorial to test three interface files. After move the tar file to directory ./util/GSI_bufr_interface and untar the file, a directory 2011060212/ will show up in the working directory.

To test read_prepbufr.exe:

ln -s 2011060212/obs/nam.t12z.prepbufr.tm00.nr.le prepbufr
./read_prepbufr.exe

To test read_gps.exe:

ln -s 2011060212/obs/gdas1.t12z.gpsro.tm00.bufr_d.le gpsbufr
./read_gps.exe

To test read_bufrtovs.exe:

ln -s 2011060212/obs/gdas1.t12z.1bmhs.tm00.bufr_d.le bufrtovs
./read_bufrtovs.exe
To check other TOVS radiance files, the observation type has to be changed to:
obstype='amsua' to run
ln -s 2011060212/obs/gdas1.t12z.1bamua.tm00.bufr_d.le bufrtovs
./read_bufrtovs.exe
or
obstype='amsub' to run
ln -s 2011060212/obs/gdas1.t12z.1bamub.tm00.bufr_d.le bufrtovs
./read_bufrtovs.exe

There is no airs BUFR file in the tutorial case. We have to download the file again from (here (308M)) to the working directory. Then test the airs decoding as:

ln -s gdas1.t12z.airsev.tm00.bufr_d.le airsbufr
./read_airs.exe

User may notice that, except for ./read_bufrtovs.exe , these executables did not write observations or other information the screen. Users are suggested to change the code to write observations from the BUFR/PrepBUFR file to the screen for practice.

Also, please note we use little Endian BUFR files as the examples because we are running these executables on Linux machine.