How to obtain variable backscattering coefficient? I mean the real number value because I have already understood that Sigma0 obtained with calibration is a backscattering coefficient but still can not understand how can I obtain the number value from it. Thanks in advance.

The value in every pixel after calibration to Sigma0 is the backscattering coefficient. It is not a coefficient as in an equation which is constant for an entire image.

You see the pixel values in the Pixel Explorer, but you can also use the pin manager or the statistics tool combines with a polygon geometry.

If this does not answer your question, please provide an example of what you mean.

Okay, understood. I wanted to find NRPB value for crop NDVI monitoring using Sentinel 1. However, I could not understand the formula of NRPB (attached below), please can you explain what values should I take if I have backscatter coefficient for every pixel, I mean should I sum them all or take an average?

You use the bands in the Band Math operator to create the equation. This will then be calculated for every pixel.

Please have a look how map algebra works in principle.

Thank you, your answer helped me a lot!