Near-Infrared (NIR) Reflectance
Definition
The portion of the electromagnetic spectrum (700-1200 nm) that healthy green vegetation reflects strongly due to the structure of chloroplasts. Stressed, sparse, or compositionally different vegetation reflects NIR differently, creating a detectable contrast in aerial or drone imagery.
- Wavelength range
- 700 to 1200 nm
- Strong reflector
- Healthy green vegetation
- Cause
- Internal chloroplast leaf structure
- Forensic use
- Detecting stressed or disturbed vegetation from imagery
Common questions
Why does vegetation stress from a buried body change NIR reflectance?+
Roots disturbed or covered by burial disrupt normal plant growth, which alters leaf cell structure and water content, and that change reduces or shifts NIR reflectance relative to undisturbed nearby vegetation, producing a visible contrast in NIR-sensitive imagery even before any visible surface change appears.
Does NIR reflectance analysis work the same way for grassland and forest canopy sites?+
The underlying principle is the same, but dense forest canopy can mask ground-level disturbance from an aerial NIR sensor, so open grassland or low-vegetation sites generally give a clearer, more directly interpretable NIR anomaly than heavily forested ground.
Related terms
- Cadaver Decomposition Island (CDI)
- The localised area of soil and vegetation altered by the decomposition fluids and gases released from a body. A CDI has a...
- Nitrophilous Plant
- A plant species that grows preferentially on nitrogen-rich soils. Examples include stinging nettle (Urtica dioica), broad-leaved dock (Rumex obtusifolius), and elder (Sambucus...
- Normalized Difference Vegetation Index (NDVI)
- A widely used spectral index calculated as (NIR - Red) / (NIR + Red). Values range from -1 to +1; healthy dense...
- Phytosociology
- The study of plant community composition and its relationship to environmental conditions. In forensic contexts, the plant assemblage over a suspected burial...
- Soil Inversion
- The displacement of soil horizons when ground is dug. Subsoil is brought to the surface and topsoil is buried, disrupting the established...