Upwelling variability off southern Indonesia over the past two millennia
Journal
Geophysical Research Letters
Journal Volume
41
Journal Issue
21
Pages
7684-7693
Date Issued
2014
Author(s)
Abstract
Modern variability in upwelling off southern Indonesia is strongly controlled by the Australian-Indonesian monsoon and the El Niño-Southern Oscillation, but multidecadal to centennial-scale variations are less clear. We present high-resolution records of upper water column temperature, thermal gradient, and relative abundances of mixed layer- and thermocline-dwelling planktonic foraminiferal species off southern Indonesia for the past two millennia that we use as proxies for upwelling variability. We find that upwelling was generally strong during the Little Ice Age (LIA) and weak during the Medieval Warm Period (MWP) and the Roman Warm Period (RWP). Upwelling is significantly anticorrelated to East Asian summer monsoonal rainfall and the zonal equatorial Pacific temperature gradient. We suggest that changes in the background state of the tropical Pacific may have substantially contributed to the centennial-scale upwelling trends observed in our records. Our results implicate the prevalence of an El Niño-like mean state during the LIA and a La Niña-like mean state during the MWP and the RWP. Key Points Upwelling variations off southern Indonesia over the past 2000 yearsUpwelling was strong during Little Ice Age and weak during Medieval Warm PeriodENSO may have contributed to changes in upwelling off southern Indonesia ©2014. American Geophysical Union. All Rights Reserved.
Subjects
Indonesia; late Holocene; upwelling
Other Subjects
Atmospheric pressure; Glacial geology; Thermal gradients; Equatorial Pacific; Indonesia; Late Holocene; Medieval Warm Period; Relative abundance; Southern oscillation; Upper water column; upwelling; Nickel; autocorrelation; climate variation; El Nino; proxy climate record; upwelling; water column; Indonesia
Type
journal article