Category: Radar (SAR)
Polarization (VV, VH, HH, HV)
Polarization describes the transmit and receive orientation of radar waves; different polarizations respond to different surface properties.
Also known as: VV, VH, HH, HV
Expanded definition
SAR systems can transmit and receive radar waves in vertical (V) or horizontal (H) orientation. VV means transmit V and receive V, while VH means transmit V and receive H.
Different polarizations interact differently with vegetation and surface roughness. For example, cross-polarized channels (VH or HV) often capture volume scattering from vegetation structure.
When comparing SAR datasets, it is important to keep polarization consistent. Mixing channels without accounting for differences can create artificial “change” in time series.
Related terms
SAR (Synthetic Aperture Radar)
SAR is an active radar sensor that works day or night and can see through clouds, measuring surface scattering rather than reflected sunlight.
Backscatter
Backscatter is the amount of radar signal returned to the sensor, influenced by roughness, moisture, and structure.
Speckle
Speckle is a grainy noise pattern in SAR imagery caused by coherent interference, typically reduced by filtering or multi-looking.