Details

Autor(en) / Beteiligte

• Leavitt, S W
• Wright, W E
• Long, A

Titel

Spatial expression of ENSO, drought, and summer monsoon in seasonal delta super(13)C of ponderosa pine tree rings in southern Arizona and New Mexico

Ist Teil von

• Journal of Geophysical Research. D. Atmospheres, 2002-09, Vol.107 (D18)

Erscheinungsjahr

2002

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• Major climatic impacts from ENSO and the North American Monsoon in the U.S. Southwest provide fortuitous circumstances for exploring the suitability of stable-carbon isotope ( delta super(13)C) composition of tree rings to represent and reconstruct interannual climate variability. We sampled ponderosa pine tree rings at eight sites in seven mountain ranges over a 500-km transect in southern Arizona and New Mexico. We developed delta super(13)C chronologies for 1985-1995 by subdividing rings into pre- and post-monsoon-onset segments based on the presence of a false-latewood band in each ring induced by the arid period immediately preceding the summer monsoon, pooling these segments from multiple trees at each site, and analyzing the cellulose component. Chronologies from two subsets of trees from the same site and separate chronologies from two different sites in the same mountain range indicate strong coherence and signal reproducibility. Additionally, the seasonal delta super(13)C patterns showed remarkable coherence across the transect, with the spatially disjunct easternmost chronology tending to be most frequently dissimilar. The delta super(13)C values of ring subdivisions before the false-latewood band are generally positively correlated with winter Southern Oscillation Indices (SOI), resulting from the ENSO teleconnection with southwestern winter/early spring precipitation. The delta super(13)C from these sites correlates with monthly Palmer Drought Severity Indices (PDSI), with the strongest correlations occurring in progressively later months from first-formed to last-formed subdivisions. The post-false latewood subdivision delta super(13)C was particularly strongly correlated with summer precipitation amount. These results confirm the strong influence of moisture on tree ring delta super(13)C and support their use in both temporal and spatial modes to infer past climate variability.