Estimation of leaf CO₂ exchange rates using a SPOT image

Abstract

With increasing atmospheric carbon dioxide (CO₂) concentrations, researchers are looking for alternative methods to quantify the terrestrial carbon sink. Although the link between CO₂ exchange and spectral reflectance has been established with net flux towers, limited research has been conducted using a leaf chamber. In an effort to determine the applications of satellite remote sensing in the estimation of carbon exchange measured with a leaf chamber, the primary objective of this study is to evaluate several broadband vegetation indices derived from a Satellite pour l'Observation de la Terre (SPOT) image in the prediction of leaf CO₂ exchange rates in a northern mixed-grass prairie ecosystem. Biophysical measurements and CO₂ exchange rates were collected from 24 sites located in and around Grasslands National Park, Saskatchewan, Canada. Linear regression showed that the Simple Ratio Vegetation Index explained 24% of the variance observed in the CO₂ exchange rates.

Acknowledgements

The researchers would like to thank the Natural Sciences and Engineering Research Council (NSERC) for financial support and Grasslands National Park for logistical support. The researchers would also like to acknowledge Chunhua Zhang, Xiaoyong Xu, Weidong Zhou, Mike Nilson and Michael Sheppard for their contributions to this project.

Notes

**Now at Department of Geography, University of Toronto Mississauga, 3359 Mississauga North Road, Mississauga, ON L5L 1C6, Canada.