arctic sea ice

multi-year ice

at least 2 m thick and wide, survived multiple summers and developed thickness and roughness

first-year ice

formed in one winter

new ice

very young, thin, smooth

thicker ice is

drier

thinner ice is

saltier/has brine inclusion

specular reflection

strong with a smooth surface, most energy reflected away

surface backscatter increased by

roughness

partial penetration

lower dielectric constant allows partial penetration

internal boundary reflection

defined layers cause contrasts and internal reflections

volume scattering/depolarization

internal heterogeneity causes volume backscatter

double bounce scattering

geometric corners can produce a strong directional return

incoming longwave radar beam will penetrate

deeper into ice (indicates thickness)

incoming shortwave radar beam will penetrate

shallower before bouncing back

microwave radar can

see through clouds and function at night