The evolutionary dynamics of El Niño Southern Oscillation (ENSO) over the last glacial period remains understudied, despite its potential in providing a “cold case” for climate sensitivity studies. Here, we investigate SE Asian-Pacific paleoclimate records to decipher the dominant underlying mechanism that governed tropical Asian-Pacific hydrology during MIS 3. Our results suggest that the glacial emergence of the Sunda Shelf likely altered the atmospheric circulation pattern in Southeast (SE) Asia and led to the realignment of rainfall patterns between Thailand and Indonesia during the last glacial period. We also propose that the long-term hydrological regime change in the tropical Asian-Pacific region during MIS 3 was mainly influenced by an El Niño-like mechanism. An intense El Niño-like condition led to strong aridity in SE Asia during mid MIS 3. By late MIS 3, an enhanced seasonality dampened the intensity of the El Niño-like conditions, thus, leading to muted aridity in SE Asia. The alternating warm and wet summer months and droughts during winter favoured the proliferation of C4 plant types in Northern Thailand from mid MIS 3 to late MIS 3.
Bibliographical noteFunding Information:
We acknowledge the support from the Swedish Research Council (VR) research grants 621-2008-2855 , 621-2011-4684 and 348-2008-6071 to Barbara Wohlfarth, and 621-2011-4916 to Rienk Smittenberg. The Delta facility, funded by the Faculty of Science, Stockholm University , provided support for the isotope analyses. LL acknowledges support from “The Featured Areas Research Center Program” within the framework of the Higher Education Sprout Project by the Ministry of Education in Taiwan, and the Ministry of Science and Technology of Taiwan (MOST) grant 106-2116-M-002 -021 to Ludvig Löwermark. We acknowledge Professor Cathy Whitlock for providing training and facility for charcoal analysis during the PhD study of SC. We thank Wichuratree Klubseang, Suda Inthongkaew and Lek, for help during field work. James Bendle and the organic geochemistry group in University of Birmingham and all those who helped in diverse ways to make this project a success are duly acknowledged.
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- El Niño
- Marine isotope Stage 3
- SE Asia and Sunda shelf
ASJC Scopus subject areas
- Global and Planetary Change
- Ecology, Evolution, Behavior and Systematics