Publication Date:
2023-08-31
Description:
The Asian-Australian monsoon (AAM) system distinctly influences global climate. However, the linkage between ENSO (El Ni~noeSouthern Oscillation) and AAM is still poorly understood over the last millennium. Here, we combined stalagmite d18O (d18Os) records with exceptionally high-resolution and high-precision chronologies to demonstrate a tight remote coupling between AAM and tropical ocean hydrology on the multi-year, decadal, and centennial timescales. Our results reveal that (1) There is a significant negative correlation between the multi-year weighted average precipitation d18O (d18Oaw) from the AAM and Southern Oscillation Index (SOI), providing a modern analogous coupling for linking stalagmite d18O (d18Os) and ENSO over the past 100 years. (2) Over the last millennium, the integrated d18Os record exhibit positive excursions during the Little Ice Age (LIA), marked by a tendency for more El Ni~no-like state conditions in the tropical Pacific, which is consistent in SST-gradient ENSO reconstruction but different to precipitation reconstruction. (3) Wavelet and power spectrum analysis for the integrated d18Os record in the AAM region show that there is a significant multi-year periodicity (2.2, 2.8, 3.5, 4.6 yr), conceding with the ENSO cycle (2e7 yr), whereas, some multi-decadal and centennial cycles (10.1, 17, 28.6, 52.7, 143 yr) are significant too. We provide evidence from instrumental and paleocliamte datasets (GNIP and NOAA) and propose a possible “circulation effect” mechanism responsible for variations of d18Os in the East Asian Monsoon (EAM) and Australian Monsoon (AM) region over the last millennium.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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