Penetration depth of interferometric synthetic-aperture radar signals in snow and ice

Digital elevation models of glaciated terrain produced by the NASA/Jet Prop ulsion Laboratory (JPL) airborne interferometric synthetic-aperture radar ( InSAR) instrument in Greenland and Alaska at the C- (5.6 cm wavelength) and L-band (24-cm) frequencies were compared with surface elevation measured f rom airborne laser altimetry to estimate the phase center of the interferom etric depth, or penetration depth, delta (p). On cold polar firn at Greenla nd summit, delta (p) = 9 +/- 2m at C- and 14 +/- 4m at L-band. On the expos ed ice surface of Jakobshavn Isbrae, west Greenland, delta (p) = 1 +/-2 m a t C- and 3 +/-3 m at L-band except on smooth, marginal ice where delta (p) = 15 +/-5 m. On colder marginal ice of northeast Greenland, delta (p) reach es 60 to 120 m at L-band. On the temperate ice of Brady Glacier, Alaska, de lta (p) is 4 +/-2 m at C- and 12 +/-6 m at L-band, with little dependence o n snow/ice conditions. The implications of the results on the scientific us e of InSAR data over snow/ice terrain is discussed.