학술논문

Anomalous widespread arid events in Asia over the past 550,000 years
Research Report
Document Type
Academic Journal
Source
PNAS Nexus. June 2023, Vol. 2 Issue 6
Subject
Texas
East Asia
Language
English
ISSN
2752-6542
Abstract
Introduction The Indian Monsoon System (IMS) is characterized by a seasonal wind reversal driven by the seasonal cycle of solar heating over Asia in which dry northeasterly winds blow from [...]
Records of element ratios obtained from the Maldives Inner Sea sediments provide a detailed view on how the Indian Monsoon System has varied at high-resolution time scales. Here, we present records from International Ocean Discovery Program (IODP) Site U1471 based on a refined chronology through the past 550,000 years. The record's high resolution and a proper approach to set the chronology allowed us to reconstruct changes in the Indian Monsoon System on a scale of anomalies and to verify their relationships with established records from the East Asian Monsoon System. On the basis of Fe/sum and Fe/Si records, it can be demonstrated that the Asia continental aridity tracks sea-level changes, while the intensity of winter monsoon winds responds to changes in Northern Hemisphere summer insolation. Furthermore, the anomalies of continental aridity and intensity of winter monsoon winds at millennial-scale events exhibit power in the precession band, nearly in antiphase with Northern Hemisphere summer insolation. These observations indicate that the insolation drove the anomalies in the Indian Summer Monsoon. The good correspondence between our record and the East Asian monsoon anomaly records suggests the occurrence of anomalous widespread arid events in Asia. Keywords: Indian Summer Monsoon, millennial-scale events, arid conditions in Asia, paleoclimate, X-ray fluorescence