PRODUCT DESCRIPTION - Vegetation indicator NPP

The net primary productivity (NPP) is a bio-physical variable describing the rate of biomass accumulation of plants. This variable can be derived from the earth observation data and be used for monitoring the growth dynamics of forest ecosystems.

What is NPP?
Gross primary production consists of the amount of light energy that is converted to chemical energy (organic compounds) by photosynthesis (autotrophy of plants) per unit of time. This chemical energy is going to two places - respiration and growth of new biomass. Net primary production omits the energy used in respiration and describes just the energy going to new plant growth. It is expressed in grams of carbon per square meter per year. It is one of major components of the terrestrial carbon cycle.

Why measure NPP?
NPP is mainly computed to establish carbon budgets (carbon sequestration and carbon emission) in a geographic region or in an eco-system. The data can be used as the basis for estimating the impact of both natural disturbances and human activities on the greenhouse gas emission.

How is NPP is estimated?
NPP can be directly assessed by measuring plant traits or harvesting plant material on the ground, but across large areas remotely sensed data can be used to estimate NPP. NPP is often calculated as a product of fAPAR (fraction of absorbed photo-synthetically active radiation) and light use efficiency (also called radiation use efficiency). In this project, a in-house built model is used to computed the NPP values.