Past atmospheric CO2 levels and the 13C/12C ratios in tree rings
TANS, PIETER P.
MOOK, WIM G.
- Publisher: Co-Action Publishing
(issn: 1600-0870, eissn: 0280-6495)
Intra-ring differences of the 13C/12C ratio in tree rings are found to be very large in four Dutch trees. In some cases differences were measured over 4‰ ?13C. Even the 13C/12C ratio averaged over entire rings sometimes still exhibits abrupt jumps of over 1‰ in ?13C from year to year. Significant correlations of ?13C in tree rings with yearly average temperature and precipitation are found. Responses of the atmosphere to a 13C labelled input of CO2 are calculated in 3 1/2 box perturbation model, consisting of an atmosphere, a biosphere, an oceanic mixed layer and a leak of the perturbation to the deep seas. The average 13C record obtained from the four trees is interpreted in terms of past biospheric growth and shrinkage by using the 3 1/2 box model.DOI: 10.1111/j.2153-3490.1980.tb00954.x