CentOS6.8下 NCL的环境配置

1. download and install ncl from http://www.ncl.ucar.edu/Download/list_of_binaries.shtml
    choose version:     ncl_ncarg-6.6.2-CentOS6.10_64bit_gnu447.tar.gz 
    install reference:  https://jingyan.baidu.com/article/ab69b2707beaea2ca7189ffc.html
    
2. install lib: "yum install libgfortran  -y"

3. add path-to/ncl_ncarg-6.6.2/bin  to PATH and set "export NCARG_ROOT=/usr/local/ncl_ncarg-6.6.2" in file "~/.bash_profile"
    PATH=$PATH:$HOME/bin
    export PATH
    PATH=/usr/local/ncl_ncarg-6.6.2/bin:$PATH
    export NCARG_ROOT=/usr/local/ncl_ncarg-6.6.2
    export PATH