Vegetation dynamics, CO₂ cycle and El Niño phenomenon

Abstract

The existence of the relation between satellite-derived vegetation index and atmospheric carbon dioxide, CO₂, was first shown by Tucker et al. who used raw global vegetation index (GVI) data. In this paper, a first order atmospheric correction is applied to the GVI data. Then the northern hemispheric CO₂ concentration cycle is compared with the GVI dynamics over the United States of America and the United Kingdom. The results show that the GVI is a measure of the degree of photosynthetic activity in the terrestrial vegetation as was shown by Tucker et al. In order to see the phase lag the results are presented as a function of time. When southern hemispheric CO₂ concentration cycle is compared with the GVI dynamics over Australia and South America (south of the equator) then it was difficult to arrive at the above conclusions. This drawback is attributed to (i) small amplitudes of CO₂ cycles arising due to less amount of photosynthetically active vegetation, and (ii) the occurrence of the so-called El Niño phenomenon on the western coast of Peru. This introduces distortions in the amplitudes of CO₂ cycle. Nevertheless, GVI and CO₂ concentration data can be used to monitor the progress that is being made in the Green Peace Movement which has been receiving some attention lately.