Abstract
Detecting the health condition in vegetation is an important activity for many applications. Economically, most important is the prediction of crop yields and precision farming to reduce fertiliser use and increase yields worldwide. Monitoring natural forest resources and reserves is a growing interest with current changes in the earth’s climate. However this is not a simple task and normally requires aerial and field measurements that are limited and expensive. Continuous satellite coverage using small satellites in a DMC-like (Disaster Monitoring Constellation) configuration could provide a cost-effective answer to this problem combined with an improved low-cost hyperspectral instrument designed specifically for this task. Monitoring vegetation conditions using a satellite-borne remote sensing instrument presents some unique challenges. The “red-edge” is defined as the abrupt reflectance change caused by the combined effects of chlorophyll absorption and leaf internal scattering inside the 680 and 750 nm band. The shift of the point of maximum slope, called the red edge position (REP), has been correlated to the chlorophyll content of green vegetation in laboratory and field measurements. Furthermore the concept is controversial, as a majority consensus agree on the existence of a relationship between the chlorophyll content and the REP value. However, many scientists still do not see a significant improvement comparing to other traditional vegetation indices. [18, 23, 26] The fundamental basis for this research has been the evaluation of the “red-edge” effect as a suitable means for improving the detection and monitoring of vegetation parameters using a satellite-borne remote-sensing instrument. The feasibility of this approach was assessed by the development of a laboratory experiment to acquire spectral data from leaves and canopies in different health conditions. Then a computational radiometric analysis (included the acquisition modelling by several sensors) was conducted to simulate the passage through the atmosphere and be able to evaluate the impact over the signals. It was then possible to compare the results with previous research works and show that the solution could provide some benefit under a single canopy scenario for a range of applications. Key words: Hyperspectral, REP, red-edge, small satellites Email: gastelum57@gmail.com WWW: http://www.eps.surrey.ac.uk/