I download a S-1 Level 1 GRD product for agricultural disaster monitoring.I want to know it’s availible or not.If it is availible,which disaster is the best using S-1.GRD product is more sensitive to soil moisture or roughness band type?
What processing should I do for GRD product?Radiomatic calibration?
S-1 GRD products are freely available for scientific use via the SciHub (https://scihub.esa.int/dhus/). The availability of data depends on the geographic location at the moment.
These data are also intended for agriculture monitoring. You might also use S-1 SLC data to get advantage of the phase info as well (e.g. coherence estimation).
There usage of the data for different applications, including disasters, vary depending on the problem in hand.
You may have a look to the already prepared tutorials for calibrating S-1 data available at STEP webpage (http://step.esa.int/main/doc/tutorials/sentinel-1-toolbox-tutorials).