LDAS-forcing

Create meteorological forcing files for Cycles or PIHM using NLDAS or GLDAS data

LDAS-forcing can download NLDAS-2 or GLDAS-2.1 forcing data from NASA GES DISC archive, and generate PIHM or Cycles weather files for given locations using NLDAS or GLDAS forcing data. NLDAS-2 and GLDAS-2.1 forcing data are a combination of model and observation based forcing data sets. NLDAS forcing is available from 1 January 1979 to now. GLDAS-2.1 forcing is available from 1 January 2000 to now.

Usage

1. Set up an Earthdata account.

2. Create a .netrc file in your home directory. This is required by NASA Earthdata for wget access.

   cd ~
   touch .netrc
   echo "machine urs.earthdata.nasa.gov login <uid> password <password>" >> .netrc
   chmod 0600 .netrc

   where uid is your user name and password is your Earthdata login password.

3. Download the code from the release page.

4. Use location.txt file to add locations of interest.

5. To use the code, run

   python3 LDAS-forcing.py --ldas {GLDAS,NLDAS} --model {Cycles,PIHM} --start START --end END

   The option ldas is the choice of LDAS, which can be GLDAS or NLDAS. The option model is the choice of model, which can be Cycles or PIHM. The options start and end are the start and end dates, which should be in the format of YYYY-MM-DD.

NOTE: The script requires Python netCDF4 module. The package can be installed using

pip install netcdf4

Penn State ICDS ROAR users will need to create a Conda environment to install Python packages. The following instruction will create a Conda environment named my_root, and install the netCDF4 package in the environment.

Python netCDF4 package installation on Penn State ICDS ROAR system

module purge
module load anaconda3
conda create -y -n my_root --clone="/opt/aci/sw/anaconda3/2020.07_gcc-4.8.5-bzb"

source activate my_root
conda install -y -c anaconda netcdf4

You can also run the install_roar.sh script to install the package.

You will need to activate the environment to run the LDAS-forcing script:

module purge
module load anaconda3
source activate my_root

The enviroment can be deactivated using

conda deactivate my_root