SMAP-HydroBlocks (SMAP-HB) is a hyper-resolution satellite-based surface soil moisture product that combines NASA's Soil Moisture Active-Passive (SMAP) L3 Enhance product, hyper-resolution land surface modeling, radiative transfer modeling, machine learning, and in-situ observations. This dataset reports the surface soil moisture (top 5-cm of the soil layer) in volumetric unit (m3/m3). Data is available across the continental United States at an effective 30-m spatial resolution (2015–2019). Retrievals are organized 6h, but are only reported at the time of SMAP retrieval. This script post-process the SMAP-HydroBlocks dataset from the Hydrological Response Unit (HRU) space (time, hru) into the geographically gridded space (time, latitude, longitude) using the Plate Carrée projection. Data can be output in Zarr and/or netCDF4 format.
git clone https://github.com/NoemiVergopolan/SMAP-HydroBlocks_postprocessing.git
cd SMAP-HydroBlocks_postprocessing
2. Download the SMAP-HydroBlocks Database from https://doi.org/10.5281/zenodo.5206725 and unzip it
wget https://zenodo.org/record/5206725/files/SMAP-HB_hru_6h.zip
unzip SMAP-HB_hru_6h.zip
Option 1 – Create a conda environment from the yml file
conda env create --name mapping -f yml/github/environment.yml
source activate mapping
Option 2 – Create a conda environment yourself:
conda create -n mapping -y
source activate mapping
conda install -c conda-forge numpy xarray rioxarray pandas dask netcdf4 zarr mpi4py xesmf esmpy
python ./SMAPHB_hru2grid.py
Gridded SMAP-HydroBlocks data will be saved on SMAPHB_sample folder. Please edit the SMAPHB_hru2grid.py script to change the desired spatial extent, time period, time resolution, data format, compression level, output file and folder name, etc.
The remapping can be performed in a multi-core setup with mpi_run = True in SMAPHB_hru2grid.py and run as:
mpirun -np <number of processes> python ./SMAPHB_hru2grid.py
There is an experimental feature that allows remapping the SMAP-HydroBlocks data at 30-m resolution to a coarser spatial resolution (e.g., 100m, 500m, 1000m, etc.). This feature relies on the xESMF library, which currently does not provide MPI parallel support. Thus, to remap SMAP-HydroBlocks data to a coarse spatial resolution, please edit SMAPHB_hru2grid.py and set mpi_run = False and final_spatial_resolution = <desire resolution in meters>. Run the script as:
python ./SMAPHB_hru2grid.py
SMAP-HydroBlocks is a very big dataset. If remapped entirely at a daily scale comprises ~120TB of data in maximum compression (option 9). This script allows for post-processing subsets of the dataset according to the user's needs and resources. For example, SMAP-HydroBlocks mapped to a 30-meter daily resolution, at ~ 50km x 50km domain, for a 1 year period, with maximum compression [option 9], is expected to output 786 MB of NetCDF files or 656 MB of Zarr storage. As such, please keep in mind that the domain extent, time period, temporal resolution, and compression option selected will determine runtime and data storage requirements.
Please cite the following paper when using the dataset in any publication:
Vergopolan, N., Chaney, N. W., Beck, H. E., Pan, M., Sheffield, J., Chan, S., & Wood, E. F. (2020). Combining hyper-resolution land surface modeling with SMAP brightness temperatures to obtain 30-m soil moisture estimates. Remote Sensing of Environment, 242, 111740. https://doi.org/10.1016/j.rse.2020.111740
Vergopolan, N., Chaney, N.W., Pan, M. et al. SMAP-HydroBlocks, a 30-m satellite-based soil moisture dataset for the conterminous US. Sci Data 8, 264 (2021). https://doi.org/10.1038/s41597-021-01050-2
- Noemi Vergopolan, Princeton University
- Website: www.waterai.earth/smaphb
- Email: noemi@princeton.edu