Millennial-scale fluctuations in water volume transported by the Tsushima Warm Current in the Japan Sea during the Holocene
Millennial-scale fluctuations in water volume transported by the Tsushima Warm Current in the Japan Sea during the Holocene
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全新世日本海对马暖流输送水量的千年尺度波动
DOI：
10.1016/j.gloplacha.2019.103028
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发表时间：
2019
影响因子：
3.9
通讯作者：
and J. Zhang
中科院分区：
文献类型：
--
作者：
Horikawa;K.;T. Kodaira;K. Ikehara;M. Murayama;and J. Zhang
对马暖流(TWC)的体积输送的周期性变化从全新世日本岛屿附近的日本南部海域的硅藻记录中得到了论证。虽然这一现象尚未得到各种替代数据的证实，但确定是否发生了这些海洋变化对于澄清日本南部海洋变化的性质至关重要。本文对日本南部13个表层沉积物中浅水新球藻的镁钙比和氧同位素(δ~(18)O)进行了耦合分析，提出了一个新的镁/钙温度定标公式(Mg/Ca = 0.311 ×EXP(0.07 × T))，作为春季海表面温度的代用。利用新开发的特定物种的镁/钙古测温仪，我们重建了过去6800年来日本南部海域YK10-7-PC09岩心的海温变率。6200-6000、4900-4500、4200-3800、2600-2100和900-400卡的SST记录清楚地代表了五个较暖的时期。年BP，与之前发表的硅藻记录几乎一致。这些较暖的事件也与TWC北端温暖软体动物聚集增加的时期相对应，表明SST较高的时期可以被视为TWC运量增加的反映。我们解释了一个模型研究的结果，该结果表明，较高的太阳辐照度引发了类似北极涛动(AO)的正向空间格局，而太平洋年代际涛动(PDO)的负相位意味着在多个百年到千年的时间尺度上TWC体积输送的增加(减少)是由高(低)太阳辐射通过AO和PDO之间的潜在联系引起的。考虑到全新世中期的火山喷发比全新世晚期的火山喷发规模更大、频率更高，火山强迫对全新世中期海温输运的影响可能更为显著，从这一时期高度变化的海温可以看出，海温在5900 cal左右明显下降。年BP和~6400 卡。英国石油公司。日本海南部海温的千年尺度波动将对过去6800 年来毗邻日本海的日本北部岛屿的植被演变和人类适应产生很大影响。
Cyclic changes in volume transport of the Tsushima Warm Current (TWC) have been argued from diatom records in the southern Japan Sea off the Japanese islands during the Holocene. Although this phenomenon has not yet been confirmed by various proxy data, determining whether or not these oceanographic changes occurred is crucial for clarifying the nature of oceanographic changes in the southern Japan Sea. Here, we conducted a coupled analysis of Mg/Ca ratios and oxygen isotopes (δ18O) in shallow-dwellingNeogloboquadrina incomptafrom 13 core-top sediments in southern Japan, and developed a new equation for Mg/Ca temperature calibration (Mg/Ca = 0.311 ×exp(0.07 × T)) as a proxy for spring sea surface temperature (SST). Using the newly developed, species-specific Mg/Ca-paleothermometry, we reconstructed SST variability for the past 6800 years from core YK10-7-PC09 in the southern Japan Sea. The Mg/Ca-derived SST record clearly represented five warmer periods at 6200–6000, 4900–4500, 4200–3800, 2600–2100, and 900–400 cal. year BP, almost consistent with previously published diatom records. These warmer events also corresponded to the periods in which warm molluscan assemblages increased at the northern end of the TWC, suggesting that periods of higher SST can be seen as reflecting the increased volume transport of the TWC. We interpreted the results of a model study showing that higher solar irradiance provoked positive Arctic Oscillation (AO)-like spatial patterns and the negative phase of the Pacific Decadal Oscillation (PDO) to mean that increased (reduced) TWC volume transport on the multi-centennial to millennial time scales was caused by high (low) solar insolation via a potential link between AO and PDO. Given that larger and more frequent volcanic eruptions occurred in the mid Holocene than in the late Holocene, volcanic forcing on the TWC volume transport changes would have been more significant during the former, as seen in the highly variable SST from this period and distinct decreases in SST around ~5900 cal. year BP and ~6400 cal. year BP. The millennial-scale fluctuations seen in SSTs in the southern Japan Sea would have had a large impact on the evolution of vegetation and human adaptation in the northern Japanese islands, adjacent to the Japan Sea, over the last 6800 years.