Extended Cave Drip Water Time Series Captures the 2015-2016 El Niño in Northern Borneo
Abstract
Time series of cave drip water oxygen isotopes (δ18O) provide site-specific assessments of the contributions of climate and karst processes to stalagmite δ18O records employed for hydroclimate reconstructions. We present ~12-year-long time series of biweekly cave drip water δ18O variations from three sites as well as a daily resolved local rainfall δ18O record from Gunung Mulu National Park in northern Borneo. Drip water δ18O variations closely match rainfall δ18O variations averaged over the preceding 3-18 months. We observe coherent interannual drip water δ18O variability of ~3‰ to 5‰ related to the El Niño-Southern Oscillation (ENSO), with sustained positive rainfall and drip water δ18O anomalies observed during the 2015/2016 El Niño. Evidence of nonlinear behavior at one of three drip water monitoring sites implies a time-varying contribution from a longer-term reservoir. Our results suggest that well-replicated, high-resolution stalagmite δ18O reconstructions from Mulu could characterize past ENSO-related variability in regional hydroclimate.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- March 2020
- DOI:
- 10.1029/2019GL086363
- Bibcode:
- 2020GeoRL..4786363E
- Keywords:
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- El Nino;
- ENSO;
- oxygen isotopes;
- cave drip waters;
- tropical rainfall;
- tropical karst