Influence of East Asian Monsoon and ENSO to the Holocene Hydroclimate deduced from Northwestern Pacific corals

东亚季风和ENSO对西北太平洋珊瑚全新世水文气候的影响

• 批准号: 20J14252
• 负责人: ギャラス ケビン
• 金额: $ 1.34万
• 依托单位: Hokkaido University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for JSPS Fellows
• 财政年份: 2020
• 资助国家: 日本
• 起止时间: 2020-04-24 至 2022-03-31
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-20J14252/
• 关键词: corals; East Asian Monsoon; ENSO; isotope geochemistry; Sr/Ca; sclerochronology; radiocarbon dating; paleoclimatology; monsoon; ITCZ; paleoenvironment; paleoclimate; Japan; Philippines

Twenty-four Porites samples were collected from Kikaijima, Japan and Northwest Luzon, Philippines. Sr/Ca-based reconstructed mean, summer, and winter SSTs from 4960 yrBP coral show higher values relative to the modern SST in Kikaijima. 5712 and 3235 yr BP were relatively cooler than the present-day. Reconstructed mean SST from 4200 yr BP coral from Northwest Luzon was comparable to the present-day but the duration of warmer months was shorter. The tropical Philippines was warmer than subtropical Southern Japan during mid- to late Holocene transition as supported by geochemical and coral growth evidence.The ocean condition in Northwestern Pacific is modulated by the seasonal shift of monsoon circulation with warm (cool) sea surface temperature (SST), high (low) rainfall, low (high) salinity and negative (positive) δ18Oseawater during EASM (EAWM). However, the timing of these seasonal signals varies in different time-windows across the tropical and subtropical region. Together with δ18Ocoral records of previous studies from Southern Japan, we demonstrate the weakening of EASM rainfall from mid- to late Holocene. Negative δ18Oseawater and δ13Ccoral define the duration of the EASM in Northern Philippines from June to November, which was relatively longer than the present-day. In contrast to the sustained warm (28-30°C) modern-day SST, our 4200 BP coral suggests that sudden drop of tropical SST in August has reduced the meridional (15-30°N) SST gradient and moisture supply in extratropical East Asia.

二十四个滨珊瑚样本采集自日本喜界岛和菲律宾吕宋岛西北部。基于 4960 年BP 珊瑚的 Sr/Ca 重建的平均、夏季和冬季海表温度相对于喜界岛的现代海表温度显示出更高的值。 5712年和3235年BP比现在相对凉爽。 根据吕宋岛西北部距今 4200 年的珊瑚重建的平均海表温度与现在相当，但温暖月份的持续时间较短。在地球化学和珊瑚生长证据的支持下，在全新世中晚期过渡期间，热带菲律宾比亚热带日本南部温暖。西北太平洋的海洋状况受到季风环流季节性变化的调节，东亚夏季风（EAWM）期间海面温度（SST）温暖（凉爽），降雨量高（低），盐度低（高），δ18O海水负（正）。然而，这些季节性信号的时间在热带和亚热带地区的不同时间窗口中有所不同。 结合之前日本南部研究的 δ18Ocoral 记录，我们证明了 EASM 降雨从全新世中晚期开始减弱。负δ18O海水和δ13C珊瑚定义了菲律宾北部东亚夏季风的持续时间为6月至11月，比现在相对较长。与持续温暖（28-30°C）的现代海表温度相比，我们距今4200年的珊瑚表明，8月份热带海表温度突然下降，减少了温带东亚经向（15-30°N）海表温度梯度和水分供应。

项目成果

Growth variations of precisely-dated fossil corals from NW Pacific: measurements from 2D X-ray imaging.

西北太平洋精确年代的珊瑚化石的生长变化：二维 X 射线成像测量。

• 发表时间: 2020
• 作者: Garas;KL. Watanabe;T.;Yamazaki;A.;Bautista;A.;Matuszaki;H.
• 通讯作者: H.

Growth Patterns and AMS-14C Age Dates of Fossil Corals from Northwest Pacific

西北太平洋珊瑚化石的生长模式和 AMS-14C 年龄

• DOI: 10.56899/151.01.24
• 发表时间: 2022
• 期刊: Philippine Journal of Science
• 作者: Garas Kevin;Watanabe Tsuyoshi;Yamazaki Atsuko;Bautista Angel;Matsuzaki Hiroyuki
• 通讯作者: Matsuzaki Hiroyuki

Evaluating the diagenetic imprints on geochemical climate proxies in fossil corals from NW Luzon (Philippines)

评估吕宋岛西北部珊瑚化石中地球化学气候代理的成岩印记（菲律宾）

• 发表时间: 2020
• 作者: Garas;KL. Watanabe;T.;Yamazaki;A.;Leido;MLSV.;Lacbawan;HA.
• 通讯作者: HA.

The East Asian summer monsoon variability around 4200 years ago recorded in coral from Northwestern Philippines (Luzon Island)

菲律宾西北部（吕宋岛）的珊瑚记录了大约4200年前的东亚夏季风变化

• 发表时间: 2020
• 作者: Garas;KL. Watanabe;T.;Yamazaki;A. Kase;T.;Aguilar;YM.;Dela Cruz;LG
• 通讯作者: LG

Hydroclimate seasonality during mid- to late Holocene transition: Evidence of East Asian Monsoon dynamics from fossil corals

全新世中晚期过渡期间的水文气候季节性：来自化石珊瑚的东亚季风动态的证据

• 发表时间: 2021
• 作者: Garas. K.;Watanabe. T., Yamazaki. Y.;Komagoe. T.
• 通讯作者: Komagoe. T.