can anyone please tell me why does the backscatter of some features of SAR images comes to be lower than the theoretical NESZ mentioned with the sensor specification??
I have the same doubt. According to the documentation the NESZ is -22 for IW mode Sentinel-1 data.
When I checked the historgram of one the tile I found most of the data lie below -22 dB (NESZ) as can be seen in the image below.
Is it an issue with the calibration?