Community ENKF V1.3 Online Tutorial | Getting Started > Downloading and Build EnKF System

DOWNLOAD AND BUILD THE COMMUNITY ENKF SYSTEM

Download GSI/EnKF system

This exercise is intended to give you practice building the GSI/EnKF system. This version of GSI/EnKF system includes a WRF I/O library. There are no need to build the WRF model for this version GSI building.

The community GSI resources, including source code, build system, utilities, and fix files, are available for download from the DTC community GSI users website: downloads

The code downloads will result in the following tar file:

comGSIv3.7_EnKFv1.3.tar.gz

GSI requires use of CRTM coefficients to analyze satellite radiance observations. Due to their large size, these are available as a separate tarfile available for download by selecting the link: CRTM 2.3.0 Big_Endian coefficients tarball

The tars file may be unpacked using the UNIX commands:

tar -zxvf comGSIv3.7_EnKFv1.3.tar.gz

 

This creates the top level GSI directory: comGSIv3.7_EnKFv1.3

Setting up the machine environment

Set the necessary paths for using your selected compiler, such as loading the appropriate modules or modifying your path variable.

Before configuring the GSI/EnKF code to be built, at least one, and no more than two environment variables must be set.

• NETCDF: the path to the NETCDF libraries
• LAPACK_PATH: the path to the LAPACK math libraries

For more detail, see EnKFv1.3 Users' Guide Chapter 2.

Building GSI v3.7 as observer and EnKF v1.3

This version GSI can ONLY be compiled with Cmake ( the same process as building GSI only). 

First create a building directory (any name works) outside the GSI directory:

mkdir build

Then, get into this building directory

cd build

Now run cmake to configure makefile by typing:

cmake ${Path To GSI Home Directory}/comGSIv3.7_EnKFv1.3

 

Cmake will check your computer environment and generate the makefile. A successful cmake run should end with:

-- Configuring done 
-- Generating done 
-- Build files have been written to: (Path_of_this_directory)/build

The building directory includes many new file and directories generated from Cmake:

bin cmake_install.cmake include Makefile Testing 
CMakeCache.txt CTestTestfile.cmake lib regression_var.out util 
CMakeFiles DartConfiguration.tcl libsrc src 

Now, we can simply run make to compile the GSI/EnKF and its untilities:

make

If the compilation is successful, the executable gsi.x, enkf.x, will be created in the ./bin directory. If the compilation is not successful, run make with make VERBOSE=1 to collect more information on errors.

After successfully compiling GSI and EnKF, the user can now run practice cases.