I think it's because they're scanning in two different wavelengths: > In a first, the satellite combines two synthetic aperture radar (SAR) systems: an L-band

I think it's because they're scanning in two different wavelengths: > In a first, the satellite combines two synthetic aperture radar (SAR) systems: an L-band system that can see through clouds and forest canopy, and an S-band system that can see through clouds as well but is more sensitive to light vegetation and moisture in snow.