I see this old conversation still is unsolved. maybe a year later someone can tell something more.
As seen in image, I have a similar stripe pattern for average-backscatter images.
Stripes appear in many, almost all, images this summer, so I guess it is not product-related.
In image above, half is orbit 131, half 160. Stripes change their direction all over the image and over time, it might come from sensor? Between temporally different images over one are, stripes sometimes are wider, sometimes narrower, sometimes brighter than other times.
Procesing chain of S1 SLC data is basically similar as @steekhutzie's:
1. Topsar - Split
2. Apply orbit file
3. Calibration (to complex numbers)
6. Stack averaging
8. Terrain correction
9. convert to dB
10. save as geotiff
I process all sequential S1 acquisitions. Maybe stripes come from S1A or S1B? On stack averaging step, also maximum backscatter between two dates is calculated, but no stripes there.
Maybe stripes are created by incorrect processing sequence? Perhaps somebody can suggest.