Tree-ring based hydroclimate reconstruction over northern Vietnam from Fokienia hodginsii: eighteenth century mega-drought and tropical Pacific influence

Publication Type  Journal Article
Year of Publication  2009
Authors  Sano, M.; Buckley, B. M.; Sweda, T.
Journal Title  Climate Dynamics
Volume  33
Issue  2-3
Pages  331-340
Journal Date  Aug
ISBN Number  0930-7575
Accession Number  ISI:000267103700012
Key Words  dendrochronology; vietnam; pdsi; fokienia hodginsii; enso; nino-southern-oscillation; summer monsoon rainfall; united-states; growth rings; time-series; thailand; temperature; variability; patterns; signal; tree-rings
Abstract  

We present here the first statistically calibrated and verified tree-ring reconstruction of climate from continental Southeast Asia. The reconstructed variable is March-May (MAM) Palmer Drought Severity Index (PDSI) based on ring widths from 22 trees (42 radial cores) of rare and long-lived conifer, Fokienia hodginsii (Po Mu as locally called) from northern Vietnam. This is the first published tree ring chronology from Vietnam as well as the first for this species. Spanning 535 years, this is the longest cross-dated tree-ring series yet produced from continental Southeast Asia. Response analysis revealed that the annual growth of Fokienia at this site was mostly governed by soil moisture in the pre-monsoon season. The reconstruction passed the calibration-verification tests commonly used in dendroclimatology, and revealed two prominent periods of drought in the mid-eighteenth and late-nineteenth centuries. The former lasted nearly 30 years and was concurrent with a similar drought over northwestern Thailand inferred from teak rings, suggesting a "mega-drought" extending across Indochina in the eighteenth century. Both of our reconstructed droughts are consistent with the periods of warm sea surface temperature (SST) anomalies in the tropical Pacific. Spatial correlation analyses with global SST indicated that ENSO-like anomalies might play a role in modulating droughts over the region, with El Nio (warm) phases resulting in reduced rainfall. However, significant correlation was also seen with SST over the Indian Ocean and the north Pacific, suggesting that ENSO is not the only factor affecting the climate of the area. Spectral analyses revealed significant peaks in the range of 53.9-78.8 years as well as in the ENSO-variability range of 2.0 to 3.2 years.

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URL  <Go to ISI>://000267103700012
DOI  DOI 10.1007/s00382-008-0454-y