High-Resolution Evidence for Middle Holocene East Asian Winter and Summer Monsoon Variations: Snapshots of Fossil Coral Records

Ryuji Asami, Natsumi Yoshimura, Hiroto Toriyabe, Shogo Minei, Ryuichi Shinjo, Chuki Hongo, Takashi Sakamaki, Kazuhiko Fujita

研究成果: Article査読

5 被引用数 (Scopus)

抄録

We first generated 53-, 4-, 10-, and 9-year-long bimonthly time series of oxygen isotopes (δ18O), Sr/Ca, and U/Ca from 4.4 and 4.9 ka corals in Okinawa, Japan. Results indicate that the mid-Holocene sea surface temperature (SST) and seawater δ18O were <1°C lower and 0.1–0.2‰ higher than today. Spectral analyses of reconstructed SST and seawater δ18O time series revealed East Asia monsoon (EAM) and El Niño/Southern Oscillation (ENSO) variations. Moreover, the latter had a dominant component of decade-scale hydrologic variations. The Sr/Ca and U/Ca variations with removal of the ENSO component showed larger fluctuations by ~2°C in winter and ~0.6°C in summer at 4.4 ka relative to today, demonstrating (slightly) greater influences of the EAM variation on the northwestern subtropical Pacific in winter (summer) at that time, which are probably caused by enhancement of the EAM intensity and/or a southward migration of the latitudinal circulation.

本文言語English
論文番号e2020GL088509
ジャーナルGeophysical Research Letters
47
16
DOI
出版ステータスPublished - 2020 8 28

ASJC Scopus subject areas

  • 地球物理学
  • 地球惑星科学(全般)

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