Sampling strategy and climatic implications of tree-ring stable isotopes on the southeast Tibetan Plateau

C. Shi (1, 2, 3) , Valérie Masson-Delmotte (3, 4) , Camille Risi (5, 6) , T. Eglin (3) , M. Stievenard (3, 4, 7) , M. Pierre (3, 7) , X. Wang (1, 8) , J. Gao (9, 2) , Francois-Marie Breon (3, 10) , Q.-B. Zhang (1) , V. Daux (3, 7, 4)

1 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
2 Graduate School of Chinese Academy of Sciences, Beijing 100049, China
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 GLACCIOS - Glaces et Continents, Climats et Isotopes Stables
5 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
6 CIRES - Cooperative Institute for Research in Environmental Sciences
7 GEOTRAC - Géochrononologie Traceurs Archéométrie
8 College of Forestry, Northeast Forestry University, 26 Hexing Road, Harbin, 150040, China
9 Key Lab. of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China
10 SATINV - Modélisation INVerse pour les mesures atmosphériques et SATellitaires

We explore the potential of tree-ring cellulose d18O and d13C records for reconstructing climate variability in the southeast Tibetan Plateau. Our sampling strategy was designed to investigate intra and inter-tree variability, and the effects of the age of tree on d18O variation. We show that intra-tree d13C and d18O variability is negligible, and inter-tree coherence is sufficient to build robust tree-ring d18O or d13C chronologies based on only four trees. There is no evidence of an age effect regarding d18O, in contrast with tree-ring width. In our warm and moist sampling site, young tree d13C is not clearly correlated with monthly mean meteorological data. Tree-ring d18O appears significantly anti-correlated with summer precipitation amount, regional cloud cover, and relative humidity. Simulations conducted with the ORCHIDEE land surface model confirm the observed contribution of relative humidity to tree cellulose d18O, and explain the weak correlation of d13C with climate by the non-linear integration linked with photosynthesis. Altogether, the tree-ring cellulose d18O is shown to be a promising proxy to reconstruct regional summer moisture variability prior to the instrumental period. © 2010 Elsevier B.V.

Domaines: Climatologie; Géochimie

C. Shi, Valérie Masson-Delmotte, Camille Risi, T. Eglin, M. Stievenard, et al.. Sampling strategy and climatic implications of tree-ring stable isotopes on the southeast Tibetan Plateau. Earth and Planetary Science Letters, 2011, 301 (1-2), pp.307-316. ⟨10.1016/j.epsl.2010.11.014⟩. ⟨hal-01120103⟩