Why are red and near infrared bands used in the NDVI vegetation index?

As shown below, Normalized Difference Vegetation Index (NDVI) uses the NIR and red channels in its formula. Healthy vegetation (chlorophyll) reflects more near-infrared (NIR) and green light compared to other wavelengths. But it absorbs more red and blue light. This is why our eyes see vegetation as the color green.

Why is the relationship between red and NIR reflectance so important for vegetation studies?

HEALTHY VEGETATION Reflected near-infrared radiation can be sensed by satellites, allowing scientists to study vegetation from space. Thus, analyzing a plants spectrum of both absorption and reflection in visible and in infrared wavelengths can provide information about the plants’ health and productivity.

What is near infrared used for in remote sensing?

Optical remote sensing makes use of visible, near infrared and short-waveinfrared sensors to form images of the earth’s surface by detecting thesolar radiation reflected from targets on the ground. Different materials reflect and absorb differently at different wavelengths.

What band is near infrared?

The Near Infrared band of the electromagnetic spectrum has wavelength range from 750 to 2500 nm. It has a frequency range from about 215 THz to 400 THz and lies close to the red end of the visible light spectrum. This spectral region has a temperature range from 740 to 3000-5000 degrees kelvin.

How does healthy green vegetation under full sun appear in an infrared photo?

Healthy vegetation (left) absorbs most of the visible light that hits it, and reflects a large portion of the near-infrared light. Unhealthy or sparse vegetation (right) reflects more visible light and less near-infrared light.

Why do plants reflect near-infrared light?

Due to the high reflectances of the infrared range, healthy plants (a lot of chlorophyll and stable cell walls) stick out in the infrared band of satellite images. Due to its structure and its chemical set-up, a leaf reflects infrared light twice as intensely as green light.

What does studying the emitted and reflected infrared radiation help us to understand?

MONITORING THE EARTH Earth scientists study infrared as the thermal emission (or heat) from our planet. Instruments onboard Earth observing satellites can sense this emitted infrared radiation and use the resulting measurements to study changes in land and sea surface temperatures.

What will happen if infrared light is used for photosynthesis?

IR light stimulates growth, bloom, and photosynthesis. When you effectively use IR light for plants, you will see major benefits that would not otherwise be possible.

What is shortwave infrared?

Short Wave IR (SWIR) is a subset of the infrared band in the electromagnetic spectrum, covering the wavelengths ranging from 1.4 to 3 microns. This wavelength is not visible to human eyes and as a result can often offer a better image than what is achievable with visible light imaging.

Does green reflect infrared?

Different surfaces reflect electromagnetic waves such as the visible light in different intensities. For example, green vegetation absorbs blue and red light quite intensely whereas it reflects green and especially infrared light even more intensely. …