Common tree growth anomalies over the northeastern Tibetan Plateau during the last six centuries: implications for regional moisture change

Publication Type  Journal Article
Year of Publication  2008
Authors  Li, J. B.; Cook, E. R.; D'Arrigo, R.; Chen, F. H.; Gou, X. H.; Peng, J. F.; Huang, J. G.
Journal Title  Global Change Biology
Volume  14
Issue  9
Pages  2096-2107
Journal Date  Sep
ISBN Number  1354-1013
Accession Number  ISI:000258257700010
Key Words  tree-rings; asian monsoon; climate change; dendrochronology; moisture change; tibetan plateau; tree growth anomalies; asian summer monsoon; eurasian snow cover; interannual variability; hydrological cycle; thermal contrast; past millennium; ring chronology;

The world's hydrological cycle is believed to intensify with global warming, yet current climate models have only a limited ability to assess moisture responses at regional scales. Tree-ring records are a valuable source of information for understanding long-term, regional-scale moisture changes, particularly for large regions such as the Tibetan Plateau (TP), where the observational data are short and sparse. Here, we present a new ring-width chronology developed from Qilian Juniper (Sabina przewalskii) wood at two sites on the northeastern TP. This chronology, combined with others from the same region, demonstrates that tree growth anomalies are linked to regional late spring to early summer moisture availability. Although late monsoon season precipitation in the study area decreased during recent decades, tree growth continued to increase due to persistent moisture availability in the early monsoon season. Comparison with global sea surface temperatures (SSTs) indicates that early (late) monsoon season precipitation is closely related to tropical Pacific (Indian Ocean) SSTs, suggesting a possible seasonal shift in the dominant moisture source area for monsoonal precipitation over the northeastern TP. It is further shown that there is a very high degree of coherency regarding low-frequency tree growth anomalies over the northeastern TP during the last six centuries. The most prominent drought epoch occurred during ca. 1450-1500, which may have been caused by a significant decrease in the thermal gradient between the Eurasian continent and the tropical oceans. A persistent tree growth increase since the 1880s is coincident with global warming, suggesting an intensified early monsoon season moisture regime in the study area.


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URL  <Go to ISI>://000258257700010
DOI  DOI 10.1111/j.1365-2486.2008.01603.x