Contents lists available at ScienceDirect Quaternary International journal homepage: www.elsevier.com/locate/quaint Evidence of solar insolation and internal forcing of sea surface temperature changes in the eastern tropical Indian Ocean during the Holocene Ziye Li a,b , Min-Te Chen b,c,d,* , Da-Cheng Lin c , Xuefa Shi b,d,** , Shengfa Liu b,d , Houjie Wang a,d , Yusuke Yokoyama e,f , Chuan-Chou Shen g , Horng-Sheng Mii h , Rainer Arief Troa i , Rina Zuraida j , Eko Triarso k , Marfasran Hendrizan k a College of Marine Geosciences, Ocean University of China, Qingdao, 266100, China b Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, SOA, Qingdao, 266061, China c The Institute of Earth Sciences & Center of Excellence for the Oceans & Center of Excellence for Ocean Engineering, National Taiwan Ocean University, Taiwan d Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China e Atmosphere and Ocean Research Institute and Department of Earth and Planetary Sciences, University of Tokyo, Japan f Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology, Japan g Department of Geosciences, National Taiwan University, Taipei, 106, Taiwan h Department of Earth Sciences, National Normal University, Taipei, 106, Taiwan i Marine Research Center, Agency of Research and Human Resources for Marine and Fisheries, Jakarta, 14420, Indonesia j Marine Geological Institute, Agency for Research and Development for Energy and Mineral Resources, Bandung, 40174, Indonesia k Research Center for Geotechnology, Indonesia Institute of Sciences, 40135, Indonesia ARTICLE INFO Keywords: Sea surface temperature Asian monsoon Indo-Pacific Warm Pool Eastern Indian Ocean ENSO IOD Holocene ABSTRACT The forcing and mechanisms governing sea surface temperature (SST) variations in the Indo-Pacific Warm Pool (IPWP) are complex. Insight into the full spectrum of IPWP climate dynamics, however, is limited by the spatial and temporal coverage of the climate data. In particular, the relationships among the changes in the SSTs, the precipitation patterns mainly associated with rainfalls from Asian Monsoons (AM), and the Indian Ocean Dipole (IOD) are poorly understood. To help us further assess the climate linkages, we have reconstructed a more spatial SST pattern during the Holocene by using multiple SST proxies (alkenone unsaturation index U 37 k ' and Mg/Ca of planktic foraminifer) in the Eastern Tropical Indian Ocean (ETIO), the western margin of the IPWP based on three sedimentary cores from NW offshore of Sumatra, and offshore of Sumatra and Java (BS24, SO139-74KL, and SO184-100430). Stable hydrogen and carbon isotope records of terrestrial plant waxes from a nearby marine sediment core SO189-144KL and geochemical tracers measured from the coral reefs within the Mentawai Islands in the ETIO are used here as AM driven precipitation and IOD records in our data synthesis. Not surprisingly, our synthesis suggests that insolation plays a major role that has been responsible for the increased SSTs in ETIO since the early Holocene, while other mechanisms remain effective in determining the timing of our re- constructed SST variations. In particular, our SST pattern shares less similarity with that of coral Sr/Ca SST and is decoupled from the coral IOD events in the mid-Holocene. We interpret that our reconstructed ETIO SSTs are driven dominantly by the solar forcing, but are also affected by other internal climate mechanisms such as the local shifts in AM-controlled upwelling and precipitation, episodic reductions in the flow of warm western Pacific surface water into the Indian Ocean due to increased precipitation over the Indonesian archipelago, and long-term ENSO or IOD-like climate change. 1. Introduction The complex interplay of the El Niño-Southern Oscillation (ENSO), Asian Monsoons (AM), and Indian Ocean Dipole (IOD) have been re- cognized as primary driving mechanisms for inter-annual to decadal climatic oscillations and extremes in the Eastern Tropical Indian Ocean (ETIO) and Indo-Pacific Warm Pool (IPWP) (Rasmusson and Wallace, 1983; Trenberth and Shea, 1987; Saji et al., 1999; Saji and Yamagata, 2003; Webster et al., 1999) as documented by historical (Parthasarathy et al., 1995; Kaplan et al., 1998) and proxy records (Charles et al., 1997, https://doi.org/10.1016/j.quaint.2018.04.001 Received 2 March 2018; Received in revised form 2 April 2018; Accepted 2 April 2018 * Corresponding author. The Institute of Earth Sciences & Center of Excellence for the Oceans & Center of Excellence for Ocean Engineering, National Taiwan Ocean University, Taiwan. ** Corresponding author. Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, SOA, Qingdao, 266061, China. E-mail addresses: mtchen@mail.ntou.edu.tw (M.-T. Chen), xfshi@fio.org.cn (X. Shi), liushengfa@fio.org.cn (S. Liu). Quaternary International xxx (xxxx) xxx–xxx 1040-6182/ © 2018 Elsevier Ltd and INQUA. All rights reserved. Please cite this article as: Li, Z., Quaternary International (2018), https://doi.org/10.1016/j.quaint.2018.04.001