Synthetic Aperture Radar (SAR)
Definition
An active microwave sensor that generates its own energy pulse and measures the return from the surface. Cloud-penetrating and day/night capable. Backscatter intensity responds to surface roughness and dielectric constant, the latter driven largely by soil moisture.
Related terms
- Ground sampling distance (GSD)
- The dimension on the ground represented by one pixel in an image. A 10 m GSD means each pixel covers a 10...
- NDVI
- Normalised Difference Vegetation Index. Computed as (NIR-Red)/(NIR+Red) from multispectral imagery. Values near 1 indicate dense healthy vegetation; values near 0 indicate bare...
- NDWI
- Normalised Difference Water Index. Computed from green and near-infrared or shortwave-infrared bands. Sensitive to water content in vegetation canopy and surface soil....
- Temporal change detection
- The comparison of multi-date images of the same area to identify pixels or features that have changed between acquisition dates. A disturbed...
- Thermal infrared (TIR)
- Sensor bands measuring emitted heat radiation (approximately 8-14 micrometres). Decomposing organic matter generates heat; soil with high moisture retains heat longer than...
Explained in
- Remote Sensing: Satellite, Aerial, and UAV ApplicationsAn active microwave sensor that generates its own energy pulse and measures the return from the surface. Cloud-penetrating and day/night capable. Backscatter i...