L-band corresponds to a wavelength of 24 cm, which, in contrast to the shorter wavelengths in C-band and X-band (wavelength 5.6 cm and 3.1 cm), is characterised by a large penetration depth for the volume scatterers, like vegetation, ice, dry soil and sand. Only by using long-wavelengths L-band is it possible to penetrate thick vegetation down to the ground and, therefore, measure its vertical structure. Another decisive advantage of using long wavelength radar signals is the greatly improved temporal coherence, important for the measurement of surface deformation and glacial motion. Thus Tandem-L will allow global motion measurements of the earth’s surface with cm down to mm accuracy over long periods.
