Persistent sea surface temperature and declined sea surface salinity in the northwestern tropical Pacific over the past 7500years

Li Lo, Yung Hsiang Lai, Kuo Yen Wei, Yu Shih Lin, Horng-Sheng Mii, Chuan Chou Shen

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

To understand Holocene climate evolutions in low-latitude region of the western Pacific, paired δ18O and Mg/Ca records of planktonic foraminifer Globigerinoides ruber (250-300μm, sensu stricto, s.s.) from a marine core ORI715-21 (121.5°E, 22.7°N, water depth 760m) underneath the Kuroshio Current (KC) off eastern Taiwan were analyzed. Over the past 7500years, the geochemical proxy-inferred sea surface temperature (SST) hovered around 27-28°C and seawater δ18O (δ18OW) slowly decreased 0.2-0.4‰ for two KC sites at 22.7° and 25.3°N. Comparison with a published high-SST and high-salinity equatorial tropical Pacific record, MD98-2181 located at the Mindanao Current (MC) at 6.3°N, reveals an anomalous time interval at 3.5-1.5kyr ago (before 1950 AD). SST gradient between the MC site and two KC site decrease from 1.5-2.0°C to only 0-1°C, and δ18OW from 0.1-0.3‰ to 0‰ for this 2-kyr time window. The high SST and low gradient could result from a northward shift of the North Equatorial Current, which implies a weakened KC. The long-term descending δ18OW and increasing precipitation in the entire low-latitude western Pacific and the gradually decreasing East Asian summer monsoonal rainfall during middle-to-late Holocene is likely caused by different land and ocean responses to solar insolation and/or enhanced moisture transportation from the Atlantic to Pacific associated with the southward movement of ITCZ.

Original languageEnglish
Pages (from-to)234-239
Number of pages6
JournalJournal of Asian Earth Sciences
Volume66
DOIs
Publication statusPublished - 2013 Apr 8

Fingerprint

sea surface salinity
sea surface temperature
Holocene
intertropical convergence zone
planktonic foraminifera
insolation
temperature gradient
water depth
moisture
seawater
salinity
rainfall
climate
ocean
summer

Keywords

  • Holocene
  • Kuroshio Current
  • Mindanao Current
  • North Equatorial Current
  • Northwestern Pacific
  • Sea surface temperature
  • Seawater δO

ASJC Scopus subject areas

  • Geology
  • Earth-Surface Processes

Cite this

Persistent sea surface temperature and declined sea surface salinity in the northwestern tropical Pacific over the past 7500years. / Lo, Li; Lai, Yung Hsiang; Wei, Kuo Yen; Lin, Yu Shih; Mii, Horng-Sheng; Shen, Chuan Chou.

In: Journal of Asian Earth Sciences, Vol. 66, 08.04.2013, p. 234-239.

Research output: Contribution to journalArticle

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abstract = "To understand Holocene climate evolutions in low-latitude region of the western Pacific, paired δ18O and Mg/Ca records of planktonic foraminifer Globigerinoides ruber (250-300μm, sensu stricto, s.s.) from a marine core ORI715-21 (121.5°E, 22.7°N, water depth 760m) underneath the Kuroshio Current (KC) off eastern Taiwan were analyzed. Over the past 7500years, the geochemical proxy-inferred sea surface temperature (SST) hovered around 27-28°C and seawater δ18O (δ18OW) slowly decreased 0.2-0.4‰ for two KC sites at 22.7° and 25.3°N. Comparison with a published high-SST and high-salinity equatorial tropical Pacific record, MD98-2181 located at the Mindanao Current (MC) at 6.3°N, reveals an anomalous time interval at 3.5-1.5kyr ago (before 1950 AD). SST gradient between the MC site and two KC site decrease from 1.5-2.0°C to only 0-1°C, and δ18OW from 0.1-0.3‰ to 0‰ for this 2-kyr time window. The high SST and low gradient could result from a northward shift of the North Equatorial Current, which implies a weakened KC. The long-term descending δ18OW and increasing precipitation in the entire low-latitude western Pacific and the gradually decreasing East Asian summer monsoonal rainfall during middle-to-late Holocene is likely caused by different land and ocean responses to solar insolation and/or enhanced moisture transportation from the Atlantic to Pacific associated with the southward movement of ITCZ.",
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