Notes on Building NetCDF4 for WRF
Before building NetCDF on your system, you should make note of the following:
(1) Choosing whether to build NetCDF-3 or NetCDF-4 is simply a choice of which file format you wish to use. It has nothing to do with the version of the NetCDF software.
(2) NetCDF-4 files are actually written in HDF5.
(3) NetCDF software version 4.x supports both NetCDF-3 and NetCDF-4 file formats, while NetCDF version 3.x or earlier only supports the NetCDF-3 file format.
You should build WRF with NetCDF-3 if the following applies to you:
- All of the data you will need to access is available in NetCDF classic or 64-bit offset formats
- You would like to delay upgrading to NetCDF-4 until NetCDF-4 formats are more widely used
- You are not able to install the HDF5 1.8 software, which is required to build and install NetCDF-4
You should build WRF with NetCDF-4 if the following applies to you:
- You need to access NetCDF data that makes use of NetCDF-4 compression or chunking
- You need to access data in all NetCDF formats, including NetCDF-4 or NetCDF-4 classic model formats
Requirements for building NetCDF-4:
(a) NetCDF 4.1 or later must be installed and configured with
--enable-netcdf-4
(b) A NetCDF Fortran interface must be installed.
(c) HDF5-1.8.1 or later must be installed.
(d) HDF5 must have been built with zlib (version 1.2.3 or later).
*Some of the required software libraries may already be on your system. On Linux and Mac systems, you can use the "locate" command to search for these libraries, i.e.:
To find zlib: locate libz.{a,so}
To find hdf5: locate libhdf5.{a,so} libhdf5_hl.{a,so}
To find NetCDF: locate libnetcdf.{a,so} libnetcdf.{a,so}
Specifying the Environment for Building:
- The configure script will use 'gcc' and 'GNU' tools if they are available.
- Many users may wish to use a vendor-supplied compiler (such as Intel). This can be done by setting environment variables, such as CC, FC, etc. before the build.
Downloading and Building Necessary External Software:
The configure script will search for the necessary tools in your path. When you run configure, you may optionally use the --prefix argument to change the default installation directory. The following example shows how to install the zlib, HDF5, and NetCDF-4 libraries in the user's home directory (in /lib and /include), using an Intel compiler:
*Note: if you do not provide the --prefix option, installation will be in /usr/local, in subdirectories /lib, /include, and bin/.
zlib:
*A tested version of zlib can be found at the NetCDF-4 ftp site.
./configure --prefix=$HOME
make
make install
HDF5:
*A tested version of HDF5 can be found at the NetCDF-4 ftp site.
*For building NetCDF, it is NOT necessary to build the HDF5 Fortran, C++, or Java API's. ONLY the HDF5 C library is used.
./configure --prefix=$HOME/hdf/hdf5-1.8.9 \
--with-zlib=$HOME
make
make install
NetCDF-4:
*It is recommended to install NetCDF Version 4.2.1 or later. The below example is for Version 4.2.1.1.
*A tested version of NetCDF-4 can be found at the NetCDF-4 ftp site.
To install NetCDF 4.2.1.1
setenv LD_LIBRARY_PATH $HOME/hdf/hdf5-1.8.9/lib:$LD_LIBRARY_PATH
./configure --prefix=$HOME/netcdf/netcdf-4.2.1.1_intel \
--enable-netcdf-4 \
LDFLAGS="-L$HOME/hdf/hdf5-1.8.9/lib -L$HOME/lib" \
CPPFLAGS="-I$HOME/hdf/hdf5-1.8.9/include -I$HOME/include" \
CC=icc
make
make install
To install NetCDF-fortran-4.2
setenv LD_LIBRARY_PATH $HOME/netcdf/netcdf-4.2.1.1_intel/lib:$LD_LIBRARY_PATH
./configure --prefix=$HOME/netcdf/netcdf-4.2.1.1_intel \
LDFLAGS="-L$HOME/netcdf/netcdf-4.2.1.1_intel/lib" \
CPPFLAGS="-I$HOME/netcdf/netcdf-4.2.1.1_intel/include" \
FC=ifort
F77=ifort
Building WRF
-To turn on NetCDF-4 features, and for using NetCDF-4 formatted output for WRF, set the following environment variables before issuing the configure script:
For csh
setenv NETCDF4 1
For bask/ksh
export NETCDF4=1
-To turn off NetCDF-4 features and to use the NetCDF Classic output format for WRF, simply unset the NetCDF4 environment variable, or set it to 0 before issuing the configure script.
Specifying the Environment for Runtime
-If WRF was built with NetCDF-4 features, you will need to add the location of the NetCDF-4 library and the HDF5 library to the shared library environment variable in the login shell environment file (e.g., .cshrc, .login). Use the environment variable that is applicable to your system:
Linux: LD_LIBRARY_PATH
Mac: DYLD_LIBRARY_PATH
AIX:, LIBPATH
HP-UX: SHLIB_PATH
*The following is an example on a Linux machine:
For csh
setenv LD_LIBRARY_PATH $HOME/netcdf/netcdf-4.2.1.1_intel/lib:$HOME/hdf/hdf5-1.8.9/lib:$LD_LIBRARY_PATH
For bash/ksh
export LD_LIBRARY_PATH=$HOME/netcdf/netcdf-4.2.1.1_intel/lib:$HOME/hdf/hdf5-1.8.9/lib:$LD_LIBRARY_PATH
Creating NetCDF Classic Output Format with the WRF NetCDF-4 Format Build
-If you turned on NetCDF-4 features while configuring WRF, the default NetCDF output format will be in NetCDF-4. To output the NetCDF Classic format at runtime (for a WRF NetCDF-4 format build), set use_netcdf_classic=.true. in the &time_control section of namelist.input.
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