The EnKF code was developed by the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Lab (ESRL) in collaboration with the research community. The GSI, used by the EnKF for its observation operators, was developed jointly at NOAA, National Aeronautics and Space Administration (NASA), and National Center for Atmospheric Research (NCAR) which is operated by the University Corporation for Atmospheric Research (UCAR). NOAA, NASA, NCAR, and UCAR makes no proprietary claims, either statutory or otherwise, to this version and release of GSI and the EnKF and consider them to be in the public domain for use by any person or entity for any purpose without any fee or charge. It is requested that any EnKF user include this notice on any partial or full copies of the EnKF. GSI and the EnKF are provided on an "AS IS" basis and any warranties, either express or implied, including but not limited to implied warranties of non-infringement, originality, merchantability and fitness for a particular purpose, are disclaimed. In no event shall UCAR be liable for any damages, whatsoever, whether direct, indirect, consequential or special, that arise out of or in connection with the access, use or performance of GSI and EnKF, including infringement actions.