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This is a collection of libraries commonly known as NCEPLIBS that are required for several NCEP applications e.g. UFS, GSI, UPP, etc. For general information about NCEPLIBS, the user is referred to the Wiki.

For full documentation of each package see

For installing NCEPLIBS on NOAA HPC systems, see the hpc-stack project. To install the third-party libraries needed by NCEPLIBS, see NCEPLIBS-external.

NCEPLIBS is comprised of the following libraries:

NCEP library Description
NCEPLIBS-bacio binary I/O for the NCEP models
NCEPLIBS-bufr working with the BUFR format
EMC-crtm Community Radiative Transfer Model
NCEPLIBS-g2 coding/decoding GRIB2 messages
NCEPLIBS-g2c C decoder/encoder routines for GRIB edition 2
NCEPLIBS-g2tmpl Utilities for GRIB2 templates
NCEPLIBS-gfsio convert GFS Gaussian output into grib output
NCEPLIBS-ip general interpolation library
NCEPLIBS-landsfcutil initializing land-surface states
NCEPLIBS-ncio read the GFS forecast files
NCEPLIBS-nemsio I/O for the NCEP models using NEMS
NCEPLIBS-nemsiogfs I/O for the NEMS-GFS model
NCEPLIBS-sfcio surface files I/O
NCEPLIBS-sigio I/O on the sigma restart file of the global spectral model
NCEPLIBS-sp spectral transform library
NCEPLIBS-w3emc decoder/encoder routines for GRIB edition 1
NCEPLIBS-w3nco decoder/encoder routines for GRIB edition 1
NCEPLIBS-wrf_io lightweight WRF-IO API library for Unified Post Processor (UPP)
NCEPLIBS-ip2 general interpolation library 2
NCEPLIBS-wgrib2 interacting with, reading, writing, and manipulating grib2 files
UPP Unified Post Processor

The following projects are also related to the NCEPLIBS project:

Required Software

A supported C/C++ and Fortran compiler (see table below). Other versions may work, in particular if close to the versions listed below.

Compiler vendor Supported (tested) versions
GNU 8.3.0, 9.X.0

A supported MPI library (see table below). Other versions may work, in particular if close to the versions listed below.

MPI library Supported (tested) versions
MPICH 3.3.1, 3.3.2
MVAPICH2 2.3.3
Open MPI 3.1.5, 4.0.2
Intel MPI 2018.0.4, 2019.6.154, 2020.0.166
SGI MPT 2.19

A software stack consisting of the following third-party libraries (TPL), compiled with the same compiler and MPI library (where applicable). Other versions may work, in particular if close to the versions listed below. To install the third-party libraries needed by NCEPLIBS, see NCEPLIBS-external.

Library Supported (tested) versions
CMake cmake-3.16.3
zlib zlib-1.2.11
libpng libpng-1.6.35
libjpeg jpeg-9.1
Jasper jasper-2.0.16
HDF5 hdf5-1.10.4
NetCDF netcdf-c-4.7.3, netcdf-fortran-4.5.2

The NCEPLIBS-external project provides an convenient way to install the required TPL on supported platforms such as generic Linux/macOS systems.

Obtaining, Building, Using NCEPLIBS

Obtaining the code

Clone the repository:

git clone

Building the libraries

CMake employs an out-of-source build. Create a directory for configuring the build and cd into it:

mkdir -p build && cd build

Set the compilers, if needed, to match those being used for compiling the TPL listed above: FC, CC, and CXX environment variables can be used to point to the desired Fortran, C, and C++ compilers.

Execute cmake from inside your build directory.

cmake -DCMAKE_INSTALL_PREFIX=<nceplibs-prefix> ../NCEPLIBS

If the TPL are not located in a path recognized by cmake e.g. /usr/local, it may be necessary to provide the appropriate environment variables e.g. <package_ROOT> or CMAKE_PREFIX_PATH so that cmake is able to locate these dependencies.

The installation prefix for NCEPLIBS is provided by the cmake command-line argument -DCMAKE_INSTALL_PREFIX=<nceplibs-prefix>

To build and install:

make -j<x>

This will build and install all the NCEPLIBS and place them into the installation prefix <nceplibs-prefix>.

Additional cmake command-line options while configuring NCEPLIBS:

-DFLAT=ON|OFF - determines the installation tree heirarchy

-DDEPLOY=ON|OFF - prepares and deploys Lua modulefiles for each of the NCEPLIBS libraries. To deploy modulefiles:

make deploy

LMod Environment module system is required to load/unload these modules.

Some HPC systems use Tcl based Environment modules. NCEPLIBS provides a means to deploy Tcl module files and can be exercised as follows:

-DTCLMOD=ON - enables option to change Lua modulefiles to Tcl modulefiles for each of the NCEPLIBS libraries. To make the change:

make tcl

On machines that do not provide access to Github, a DOWNLOAD_ONLY and USE_LOCAL option is provided. To download the NCEPLIBS without building them use the cmake command line option -DDOWNLOAD_ONLY=ON. This will download all the NCEPLIBS in a local download folder. make tarball will tar and zip this folder into nceplibs.tgz which can then be transferred to the machine without GitHub access. Untar the tarball, and use the cmake command line option USE_LOCAL as -DUSE_LOCAL=ON. This will use the source code from the download directory.


NCEPLIBS can be used in any application that uses cmake to configure and build by adding -DCMAKE_PREFIX_PATH=<nceplibs-prefix> to the cmake command line during configuration.


The United States Department of Commerce (DOC) GitHub project code is provided on an "as is" basis and the user assumes responsibility for its use. DOC has relinquished control of the information and no longer has responsibility to protect the integrity, confidentiality, or availability of the information. Any claims against the Department of Commerce stemming from the use of its GitHub project will be governed by all applicable Federal law. Any reference to specific commercial products, processes, or services by service mark, trademark, manufacturer, or otherwise, does not constitute or imply their endorsement, recommendation or favoring by the Department of Commerce. The Department of Commerce seal and logo, or the seal and logo of a DOC bureau, shall not be used in any manner to imply endorsement of any commercial product or activity by DOC or the United States Government.


Top level repo containing submodules for NCEPLIBS and associated dependencies for superproject builds







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