3.2 - Fundamental factors affecting vegetation reflectance

A typical reflectance spectrum of a vegetation canopy can be subdivided into 3 parts, visible (0.40 –m 0.70 μm), near infrared NIR (0.701 – 1.3 μm) and middle-infrared (1.301 – 2.5 μm). Another optical property of the reflectance spectrum of vegetation is the abrupt transition between the strong absorption in the visible red and the strong reflectance in the NIR domain known as Red Edge.

Figure 3.3 – Reflectance spectrum of green grass subdivided into the 4 main optical properties of the reflectance spectrum of vegetation.

NOTE: The classification of the electromagnetic radiation used in this module is the most widely used in the vegetation community. The Visible is within the interval 0.40 μm - 0.70 μm; the Near Infra-red 0.701μm - 1.3μm and the Middle Infra-red 1.301μm - 2.5μm. Thus, in this module, channel 0.6μm is called Visible (VIS); channel 0.8μm - Near Infra-red (NIR) and 1.6μm - Middle Infra-red (MIR), instead of the classification used in the Satellite Meteorology community 0.6μm - Visible (VIS), 0.8μm - Visible (VIS) and 1.6μm - Near Infra-red (NIR)