Precession-paced thermocline water temperature changes in response to upwelling conditions off southern Sumatra over the past 300,000 years

Variability in Indonesian Throughflow Upper Hydrology in Response to Precession‐Induced Tropical Climate Processes Over the Past 120 kyr

“…(2009) for the past 300 kyr using the total organic carbon (TOC) content of core SO139‐74 KL retrieved south of Sumatra (Figure 6d) indicates a higher TOC content, which denotes a stronger AIWM, and vice versa. This proxy is supported by peak abundances of total coccolithophorid concentrations from the same core (Andruleit et al., 2008), total diatom concentrations from the neighboring core GeoB10038‐4 (Romero et al., 2012) and a model study (Wang et al., 2018). A comparison of the temperature profiles from core SO217‐18540 with the TOC content from core SO139‐74 KL shows that high SST and TT and small ΔT in the Flores Sea coincided with an enhanced AIWM and vice versa during the past ∼120 kyr (Figures 6a–6d).…”

“…Moreover, a recent study from Wang et al. (2018) suggests that the most remarkable feature of AIWM upwelling on orbital timescales is the occurrence of low TT at low precession. However, cross‐spectral analysis shows that the maximum TT in core SO217‐18540 only lagged the precession minima by ∼55° (∼3.5 kyr).…”

“…The Flores upwelling and the better-known Java-Sumatra upwelling are driven by the Australian-Indonesian winter monsoon (AIWM), which is part of the larger-scale Austral-Asian monsoon system. During austral winter (June-September), southeast winds drive the surface water of the Flores Sea away from the coast, initiating the Flores upwelling and subsequently reducing 10.1029/2020JC017014 3 of 17 (Carolin et al, 2013(Carolin et al, , 2016Partin et al, 2007) and the locations of deep-sea cores MD06-3067 (Bolliet et al, 2011), MD10-3340 (Dang et al, 2015), MD01-2378 (Xu et al, 2006(Xu et al, , 2008Zuraida et al, 2009), SO139-74KL (Wang et al, 2018), SO217-18515 (Zhang et al, 2018) and MD01-2386 (Jian et al, 2020). Cross-shaded areas represent the Flores Sea and Java-Sumatra upwelling areas (Gordon, 2005;Mohtadi et al, 2009).…”

“…(2008), and Wang et al. (2018) suggested that precession was the dominant forcing factor of past changes in the productivity, upper water column structure and thermocline temperature (TT) of tropical seas based on analyses of coccolithophore assemblages and planktonic foraminiferal δ 18 O and Mg/Ca.…”

“… Map of coring sites referred to in this study. The yellow star marks the location of core SO217‐18540, the yellow dots indicate the stalagmite site of Gunung Buda on Borneo (Carolin et al., 2013, 2016; Partin et al., 2007) and the locations of deep‐sea cores MD06‐3067 (Bolliet et al., 2011), MD10‐3340 (Dang et al., 2015), MD01‐2378 (Xu et al., 2006, 2008; Zuraida et al., 2009), SO139‐74KL (Wang et al., 2018), SO217‐18515 (Zhang et al., 2018) and MD01‐2386 (Jian et al., 2020). Cross‐shaded areas represent the Flores Sea and Java‐Sumatra upwelling areas (Gordon, 2005; Mohtadi et al., 2009).…”