By Somesh Kallappa Jadhav
Definition:
The Red-edge Normalized Difference Vegetation Index (ReNDVI) is a vegetation index used to estimate stem water potential and monitor plant health. It’s similar to the Normalized Difference Vegetation Index (NDVI) but utilizes the red-edge region of the spectrum (around 715 nm) for calculation, which is more sensitive to subtle changes in chlorophyll content and plant stress. Formula: RENDVI = NIR-Red Edge/ NIR+ Red Edge
▪ How it works: ReNDVI measures the difference between the reflectance of the red-edge band and the near-infrared band, normalized by their sum. This allows for a more robust assessment of vegetation health, especially in situations where traditional NDVI might be affected by factors like soil background or shading. 2.Forest Discrimination Index (FDI)
•Definition:- The Forest Discrimination Index (FDI) is a tool used in remote sensing to analyze and understand forest health, particularly in the context of mangrove forests. It helps classify vegetation density and can be used to assess forest degradation.
▪ ︎Formula:- FDI=NIR – (Red-edge +Red) ▪ ︎ How FDI Works:
• FDI typically uses spectral data from satellite imagery to differentiate between different forest types or conditions.
•It can be used to identify areas with varying levels of vegetation density and overall health.
•FDI can be combined with other indices like NDVI to provide a more comprehensive picture of forest health and vulnerability.
MCARI/OSAVI (Combined chlorophyll – SAVI Index)
Definition:-
The MCARI/OSAVI index is a combined vegetation index used in remote sensing to assess plant health, specifically focusing on chlorophyll content while minimizing soil background effects.
It integrates two indices: MCARI (Modified Chlorophyll Absorption Ratio Index) and OSAVI (Optimized Soil-Adjusted Vegetation Index). Below is an explanation of each component and their combination. MCARI is designed to estimate chlorophyll content in vegetation by analyzing the reflectance in specific wavelengths, particularly in the red, red-edge, and near-infrared (NIR) regions. It is sensitive to chlorophyll absorption and less affected by leaf area index (LAI) variations. MCARI: Measures chlorophyll absorption using specific wavelengths. Formula: MCARI = ((R700 – R670) – 0.2 * (R700 – R550)) * (R700 / R670)
How it works:
▪MCARI primarily uses reflectance data from the red and near-infrared (VNIR) regions of the electromagnetic spectrum.
▪ The index is calculated using a formula that typically involves subtracting a scaled version of the difference between VNIR and green bands from the difference between VNIR and red bands, then dividing by the VNIR band reflectance.
OSAVI :- A vegetation index that is sensitive to chlorophyll content and minimizes the effects of soil background variations Formula:- OSAVI = (R800 – R670) / (R800 + R670 + 0.16) How it Work ▪Indicate healthy, dense vegetation with high chlorophyll content.
▪Indicate less healthy, sparse vegetation, potentially with increased soil influence.
Research Contributors:
Somesh Kallappa Jadhav (Shivaji University Student)
