Temporal variation in the stable isotopes in precipitation related to the rainfall pattern in a tropical rainforest in Peninsular Malaysia

Itoh M., . and Kosugi Y., . and Takanashi S., . and Katsuyama M., . and Marryanna L., . and Tani M., . and Noguchi S., . and Siti-Aisah S., . Temporal variation in the stable isotopes in precipitation related to the rainfall pattern in a tropical rainforest in Peninsular Malaysia. pp. 349-362. ISSN 0128-1283

We present the temporal variability of the oxygen (´18O) and hydrogen (´H) isotope signatures in precipitation at Pasoh Forest Reserve (FR) a tropical rainforest in Peninsular Malaysia. We investigated the daily and seasonal variability of stable isotope signatures in precipitation particularly in relation to the effects of monsoon seasons rainfall characteristics and larger scale trends compared with those at nearby Global Network of Isotopes in Precipitation (GNIP) monitoring stations. The isotope signatures did not differ between monsoon seasons but were correlated with amount of rainfall its intensity and duration. The effect of amount of rainfall on isotope composition was clearly detected and comparable with long-term mean monthly statistics of nearby GNIP stations. Unfortunately the effect was obscured at the daily timescale and for monthly rainfall not averaged over the long-term. No large deuterium excess was detected at the daily timescale for small-scale rainfall events. The ´18O in precipitation water was more closely correlated with the 60-day antecedent rainfall index than with the amount of rainfall each day. These findings suggested that the isotopic composition in the study area was the result of a rainout on a larger scale in addition to the local scale and specific rain events.

Full text available from: Official URL: https://www.frim.gov.my/v1/jtfsonline/jtfs/v29n3/3...

Abstract

We present the temporal variability of the oxygen (´18O) and hydrogen (´H) isotope signatures in precipitation at Pasoh Forest Reserve (FR) a tropical rainforest in Peninsular Malaysia. We investigated the daily and seasonal variability of stable isotope signatures in precipitation particularly in relation to the effects of monsoon seasons rainfall characteristics and larger scale trends compared with those at nearby Global Network of Isotopes in Precipitation (GNIP) monitoring stations. The isotope signatures did not differ between monsoon seasons but were correlated with amount of rainfall its intensity and duration. The effect of amount of rainfall on isotope composition was clearly detected and comparable with long-term mean monthly statistics of nearby GNIP stations. Unfortunately the effect was obscured at the daily timescale and for monthly rainfall not averaged over the long-term. No large deuterium excess was detected at the daily timescale for small-scale rainfall events. The ´18O in precipitation water was more closely correlated with the 60-day antecedent rainfall index than with the amount of rainfall each day. These findings suggested that the isotopic composition in the study area was the result of a rainout on a larger scale in addition to the local scale and specific rain events.

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Item Type:	Article
AGROVOC Term:	Tropical rain forests
AGROVOC Term:	Isotopes
AGROVOC Term:	Precipitation
AGROVOC Term:	Rainfall patterns
AGROVOC Term:	Oxygen
AGROVOC Term:	Hydrogen
AGROVOC Term:	Monsoon climate
AGROVOC Term:	Rain intensity recorders
AGROVOC Term:	Deuterium
AGROVOC Term:	Dipterocarps
Geographical Term:	Malaysia
Depositing User:	Ms. Suzila Mohamad Kasim
Last Modified:	28 Apr 2025 05:19
URI:	http://webagris.upm.edu.my/id/eprint/23628

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