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  • Contraction of the Western Pacific Tropical Rain Belt and Weakening of the Walker Circulation: Future Lessons From the Past Two Interglacials
Title: Contraction of the Western Pacific Tropical Rain Belt and Weakening of the Walker Circulation: Future Lessons From the Past Two Interglacials
Abstract The western Pacific warm pool (WPWP) is the heat engine of the global climate system delivering vast amounts of heat and moisture to the atmosphere. Controls on regional convection, however, are numerous, making it difficult to simulate past and future changes in WPWP hydroclimate with confidence. Here, we synthesize new and previously available precipitation sensitive records from the WPWP spanning the last and present interglacial periods. We find two primary modes of rainfall variability, both driven by precession forcing, that are common to both interglacial periods: (a) a contraction of the tropical rain band across the interglacial and (b) a mid‐interglacial strengthening of the Pacific Walker Circulation (PWC). We further demonstrate that while the amplitude of the change in seasonal insolation across the Holocene is far lower than during the LIG due to the low eccentricity state of Earth's orbit, the response of regional rainfall is comparable during both interglacials, indicating a nonlinear response to the insolation forcing. Finally, we suggest an enhanced sensitivity of the PWC to non‐insolation climate forcing, including greenhouse gases and sea level change, under strongly reduced boreal fall insolation as observed during the late Holocene and late LIG.  more » « less
Award ID(s):
2432287
PAR ID:
10623827
Author(s) / Creator(s):
; ;
Publisher / Repository:
American Geophysical Union (AGU) / Wiley
Date Published:
Journal Name:
Paleoceanography and Paleoclimatology
Volume:
40
Issue:
4
ISSN:
2572-4517
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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