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| Titel |
Multiple tree-ring chronologies (ring width, δ¹³C and δ¹⁸O) reveal dry and rainy season signals in Indonesia |
| VerfasserIn |
Karina Schollaen, Ingo Heinrich, Burkhard Neuwirth, Paul Krusic, Rosanne D'Arrigo, Oka Karyanto, Gerhard Helle |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250084339
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| Zusammenfassung |
| The tropical Indonesian region plays a key role in the global climate system because of the
enormous heat and moisture exchange between ocean and atmosphere in that area. Here, we
evaluate the influence of rainfall variability on multiple tree-ring parameters of Teak (Tectona
grandis) trees growing in a lowland rain forest in Central Java (Indonesia). Three,
annually resolved, chronologies of tree-ring width, stable carbon (δ13C) and oxygen
(δ18O) isotopes were developed for the twentieth century (1900-2007). Climate
response analysis with regional rainfall data has revealed that all three tree-ring
parameters are significantly sensitive to rainfall during different intervals of the
seasonal monsoon pattern. The amount of rainfall at the beginning of the rainy
season (Sep-Nov) is important for tree-ring width, confirming previous studies. The
stable isotope records best represent slightly different sub-periods of the prime rainy
season (δ13C: Dec-May; δ18O: Nov-Feb) with negative correlations. Tree-ring δ18O
additionally responds well to peak dry season rainfall with positive correlation.
The correlations of opposite sign reflect the distinct seasonal contrast of the δ18O
signatures of rainfall during the dry (18O-enriched rain) and rainy (18O-depleted
rain) seasons in conjunction with changing rainfall amount. Dry season periods
with rainfall amounts above average have an exceptionally strong influence on
tree-ring δ18O in years with below average rainy season rainfall. In such cases, the dry
season signal reduces the signal strength of the prime rainy season in tree-ring δ18O.
However, the rainy season signal is still strong and stable over the 20th century.
Further, the δ18O record correlates with several ENSO events, supported by spectral
analysis which reveals significant peaks on the 2-4 year band. Highly resolved
intra-annual δ18O isotope analyses suggest that the signals of dry and rainy season can be
distinguished clearly and demonstrate a new way of improving our understanding
of variations and trends of the hydrological cycle at the Indonesian archipelago. |
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