Tools for SAR wind processing.
In order to use py-sar-wind, Earth topography data is required to separate between land and ocean coverage in the SAR data. We use the Mean Statistic, 30 arc-seconds global raster data grids provided by the U.S. Geological Survey (USGS; https://www.usgs.gov/coastal-changes-and-impacts/gmted2010).
In order to use the topography dataset, launch the GMTED2010 Viewer available
via https://www.usgs.gov/coastal-changes-and-impacts/gmted2010, select all the
regions, and download the "Mean - 30 arc-sec" tif-files. Add the files to a
local folder, and copy the file gmted2010_30.vrt in py-sar-wind to the same
folder as the source files (xml and tif).
Finally, add the location of the source files and the VRT file to your .bashrc-file:
export GMTED30=$HOME/GMTED/gmted2010_30.vrt
You should now be ready to install py-sar-wind.
Create conda environment:
conda env create -f sar-wind.yml
Activate the new environment:
conda activate sarwind
Install remaining dependencies:
pip install .
Sentinel-1 Synthetic Aperture Radar (SAR) data can be found and downloaded from, e.g., https://colhub.met.no/#/home provided user registration.
Since wind direction cannot be estimated directly from the SAR Normalized Radar Cross Section (NRCS), auxiliary wind direction data needs to be provided. This can be, e.g., numerical weather forecast models such as MEPS and AROME-ARCTIC in Norwegian areas and NCEP GFS globally, or reanalysis products like ERA5.
The simplest way to use py-sar-wind is to download a Sentinel-1 product, and use the global NCEP GFS dataset to get wind directions:
from sarwind.sarwind import SARWind
model_fn = ("https://pae-paha.pacioos.hawaii.edu/thredds/dodsC/"
"ncep_global/NCEP_Global_Atmospheric_Model_best.ncd")
sar_fn = "S1A_EW_GRDM_1SDV_20241103T024443_20241103T024549_056384_06E87A_B5A4.zip"
w = SARWind(sar_fn, model_fn)
Quick look at the data:
from swutils.utils import plot_wind_map
plot_wind_map(w)
Export to netCDF:
w.export("S1A_EW_GRDM_1SDV_20241103T024443_20241103T024549_056384_06E87A_B5A4.nc")
